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"""
A sub-package for efficiently dealing with polynomials.
Within the documentation for this sub-package, a "finite power series,"
i.e., a polynomial (also referred to simply as a "series") is represented
by a 1-D numpy array of the polynomial's coefficients, ordered from lowest
order term to highest. For example, array([1,2,3]) represents
``P_0 + 2*P_1 + 3*P_2``, where P_n is the n-th order basis polynomial
applicable to the specific module in question, e.g., `polynomial` (which
"wraps" the "standard" basis) or `chebyshev`. For optimal performance,
all operations on polynomials, including evaluation at an argument, are
implemented as operations on the coefficients. Additional (module-specific)
information can be found in the docstring for the module of interest.
"""
from __future__ import division, absolute_import, print_function
from .polynomial import Polynomial
from .chebyshev import Chebyshev
from .legendre import Legendre
from .hermite import Hermite
from .hermite_e import HermiteE
from .laguerre import Laguerre
from numpy.testing import _numpy_tester
test = _numpy_tester().test
bench = _numpy_tester().bench

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"""
Abstract base class for the various polynomial Classes.
The ABCPolyBase class provides the methods needed to implement the common API
for the various polynomial classes. It operates as a mixin, but uses the
abc module from the stdlib, hence it is only available for Python >= 2.6.
"""
from __future__ import division, absolute_import, print_function
from abc import ABCMeta, abstractmethod, abstractproperty
from numbers import Number
import numpy as np
from . import polyutils as pu
__all__ = ['ABCPolyBase']
class ABCPolyBase(object):
"""An abstract base class for series classes.
ABCPolyBase provides the standard Python numerical methods
'+', '-', '*', '//', '%', 'divmod', '**', and '()' along with the
methods listed below.
.. versionadded:: 1.9.0
Parameters
----------
coef : array_like
Series coefficients in order of increasing degree, i.e.,
``(1, 2, 3)`` gives ``1*P_0(x) + 2*P_1(x) + 3*P_2(x)``, where
``P_i`` is the basis polynomials of degree ``i``.
domain : (2,) array_like, optional
Domain to use. The interval ``[domain[0], domain[1]]`` is mapped
to the interval ``[window[0], window[1]]`` by shifting and scaling.
The default value is the derived class domain.
window : (2,) array_like, optional
Window, see domain for its use. The default value is the
derived class window.
Attributes
----------
coef : (N,) ndarray
Series coefficients in order of increasing degree.
domain : (2,) ndarray
Domain that is mapped to window.
window : (2,) ndarray
Window that domain is mapped to.
Class Attributes
----------------
maxpower : int
Maximum power allowed, i.e., the largest number ``n`` such that
``p(x)**n`` is allowed. This is to limit runaway polynomial size.
domain : (2,) ndarray
Default domain of the class.
window : (2,) ndarray
Default window of the class.
"""
__metaclass__ = ABCMeta
# Not hashable
__hash__ = None
# Opt out of numpy ufuncs and Python ops with ndarray subclasses.
__array_ufunc__ = None
# Limit runaway size. T_n^m has degree n*m
maxpower = 100
@abstractproperty
def domain(self):
pass
@abstractproperty
def window(self):
pass
@abstractproperty
def nickname(self):
pass
@abstractmethod
def _add(self):
pass
@abstractmethod
def _sub(self):
pass
@abstractmethod
def _mul(self):
pass
@abstractmethod
def _div(self):
pass
@abstractmethod
def _pow(self):
pass
@abstractmethod
def _val(self):
pass
@abstractmethod
def _int(self):
pass
@abstractmethod
def _der(self):
pass
@abstractmethod
def _fit(self):
pass
@abstractmethod
def _line(self):
pass
@abstractmethod
def _roots(self):
pass
@abstractmethod
def _fromroots(self):
pass
def has_samecoef(self, other):
"""Check if coefficients match.
.. versionadded:: 1.6.0
Parameters
----------
other : class instance
The other class must have the ``coef`` attribute.
Returns
-------
bool : boolean
True if the coefficients are the same, False otherwise.
"""
if len(self.coef) != len(other.coef):
return False
elif not np.all(self.coef == other.coef):
return False
else:
return True
def has_samedomain(self, other):
"""Check if domains match.
.. versionadded:: 1.6.0
Parameters
----------
other : class instance
The other class must have the ``domain`` attribute.
Returns
-------
bool : boolean
True if the domains are the same, False otherwise.
"""
return np.all(self.domain == other.domain)
def has_samewindow(self, other):
"""Check if windows match.
.. versionadded:: 1.6.0
Parameters
----------
other : class instance
The other class must have the ``window`` attribute.
Returns
-------
bool : boolean
True if the windows are the same, False otherwise.
"""
return np.all(self.window == other.window)
def has_sametype(self, other):
"""Check if types match.
.. versionadded:: 1.7.0
Parameters
----------
other : object
Class instance.
Returns
-------
bool : boolean
True if other is same class as self
"""
return isinstance(other, self.__class__)
def _get_coefficients(self, other):
"""Interpret other as polynomial coefficients.
The `other` argument is checked to see if it is of the same
class as self with identical domain and window. If so,
return its coefficients, otherwise return `other`.
.. versionadded:: 1.9.0
Parameters
----------
other : anything
Object to be checked.
Returns
-------
coef
The coefficients of`other` if it is a compatible instance,
of ABCPolyBase, otherwise `other`.
Raises
------
TypeError
When `other` is an incompatible instance of ABCPolyBase.
"""
if isinstance(other, ABCPolyBase):
if not isinstance(other, self.__class__):
raise TypeError("Polynomial types differ")
elif not np.all(self.domain == other.domain):
raise TypeError("Domains differ")
elif not np.all(self.window == other.window):
raise TypeError("Windows differ")
return other.coef
return other
def __init__(self, coef, domain=None, window=None):
[coef] = pu.as_series([coef], trim=False)
self.coef = coef
if domain is not None:
[domain] = pu.as_series([domain], trim=False)
if len(domain) != 2:
raise ValueError("Domain has wrong number of elements.")
self.domain = domain
if window is not None:
[window] = pu.as_series([window], trim=False)
if len(window) != 2:
raise ValueError("Window has wrong number of elements.")
self.window = window
def __repr__(self):
format = "%s(%s, domain=%s, window=%s)"
coef = repr(self.coef)[6:-1]
domain = repr(self.domain)[6:-1]
window = repr(self.window)[6:-1]
name = self.__class__.__name__
return format % (name, coef, domain, window)
def __str__(self):
format = "%s(%s)"
coef = str(self.coef)
name = self.nickname
return format % (name, coef)
# Pickle and copy
def __getstate__(self):
ret = self.__dict__.copy()
ret['coef'] = self.coef.copy()
ret['domain'] = self.domain.copy()
ret['window'] = self.window.copy()
return ret
def __setstate__(self, dict):
self.__dict__ = dict
# Call
def __call__(self, arg):
off, scl = pu.mapparms(self.domain, self.window)
arg = off + scl*arg
return self._val(arg, self.coef)
def __iter__(self):
return iter(self.coef)
def __len__(self):
return len(self.coef)
# Numeric properties.
def __neg__(self):
return self.__class__(-self.coef, self.domain, self.window)
def __pos__(self):
return self
def __add__(self, other):
othercoef = self._get_coefficients(other)
try:
coef = self._add(self.coef, othercoef)
except Exception:
return NotImplemented
return self.__class__(coef, self.domain, self.window)
def __sub__(self, other):
othercoef = self._get_coefficients(other)
try:
coef = self._sub(self.coef, othercoef)
except Exception:
return NotImplemented
return self.__class__(coef, self.domain, self.window)
def __mul__(self, other):
othercoef = self._get_coefficients(other)
try:
coef = self._mul(self.coef, othercoef)
except Exception:
return NotImplemented
return self.__class__(coef, self.domain, self.window)
def __div__(self, other):
# set to __floordiv__, /, for now.
return self.__floordiv__(other)
def __truediv__(self, other):
# there is no true divide if the rhs is not a Number, although it
# could return the first n elements of an infinite series.
# It is hard to see where n would come from, though.
if not isinstance(other, Number) or isinstance(other, bool):
form = "unsupported types for true division: '%s', '%s'"
raise TypeError(form % (type(self), type(other)))
return self.__floordiv__(other)
def __floordiv__(self, other):
res = self.__divmod__(other)
if res is NotImplemented:
return res
return res[0]
def __mod__(self, other):
res = self.__divmod__(other)
if res is NotImplemented:
return res
return res[1]
def __divmod__(self, other):
othercoef = self._get_coefficients(other)
try:
quo, rem = self._div(self.coef, othercoef)
except ZeroDivisionError as e:
raise e
except Exception:
return NotImplemented
quo = self.__class__(quo, self.domain, self.window)
rem = self.__class__(rem, self.domain, self.window)
return quo, rem
def __pow__(self, other):
coef = self._pow(self.coef, other, maxpower=self.maxpower)
res = self.__class__(coef, self.domain, self.window)
return res
def __radd__(self, other):
try:
coef = self._add(other, self.coef)
except Exception:
return NotImplemented
return self.__class__(coef, self.domain, self.window)
def __rsub__(self, other):
try:
coef = self._sub(other, self.coef)
except Exception:
return NotImplemented
return self.__class__(coef, self.domain, self.window)
def __rmul__(self, other):
try:
coef = self._mul(other, self.coef)
except Exception:
return NotImplemented
return self.__class__(coef, self.domain, self.window)
def __rdiv__(self, other):
# set to __floordiv__ /.
return self.__rfloordiv__(other)
def __rtruediv__(self, other):
# An instance of ABCPolyBase is not considered a
# Number.
return NotImplemented
def __rfloordiv__(self, other):
res = self.__rdivmod__(other)
if res is NotImplemented:
return res
return res[0]
def __rmod__(self, other):
res = self.__rdivmod__(other)
if res is NotImplemented:
return res
return res[1]
def __rdivmod__(self, other):
try:
quo, rem = self._div(other, self.coef)
except ZeroDivisionError as e:
raise e
except Exception:
return NotImplemented
quo = self.__class__(quo, self.domain, self.window)
rem = self.__class__(rem, self.domain, self.window)
return quo, rem
# Enhance me
# some augmented arithmetic operations could be added here
def __eq__(self, other):
res = (isinstance(other, self.__class__) and
np.all(self.domain == other.domain) and
np.all(self.window == other.window) and
(self.coef.shape == other.coef.shape) and
np.all(self.coef == other.coef))
return res
def __ne__(self, other):
return not self.__eq__(other)
#
# Extra methods.
#
def copy(self):
"""Return a copy.
Returns
-------
new_series : series
Copy of self.
"""
return self.__class__(self.coef, self.domain, self.window)
def degree(self):
"""The degree of the series.
.. versionadded:: 1.5.0
Returns
-------
degree : int
Degree of the series, one less than the number of coefficients.
"""
return len(self) - 1
def cutdeg(self, deg):
"""Truncate series to the given degree.
Reduce the degree of the series to `deg` by discarding the
high order terms. If `deg` is greater than the current degree a
copy of the current series is returned. This can be useful in least
squares where the coefficients of the high degree terms may be very
small.
.. versionadded:: 1.5.0
Parameters
----------
deg : non-negative int
The series is reduced to degree `deg` by discarding the high
order terms. The value of `deg` must be a non-negative integer.
Returns
-------
new_series : series
New instance of series with reduced degree.
"""
return self.truncate(deg + 1)
def trim(self, tol=0):
"""Remove trailing coefficients
Remove trailing coefficients until a coefficient is reached whose
absolute value greater than `tol` or the beginning of the series is
reached. If all the coefficients would be removed the series is set
to ``[0]``. A new series instance is returned with the new
coefficients. The current instance remains unchanged.
Parameters
----------
tol : non-negative number.
All trailing coefficients less than `tol` will be removed.
Returns
-------
new_series : series
Contains the new set of coefficients.
"""
coef = pu.trimcoef(self.coef, tol)
return self.__class__(coef, self.domain, self.window)
def truncate(self, size):
"""Truncate series to length `size`.
Reduce the series to length `size` by discarding the high
degree terms. The value of `size` must be a positive integer. This
can be useful in least squares where the coefficients of the
high degree terms may be very small.
Parameters
----------
size : positive int
The series is reduced to length `size` by discarding the high
degree terms. The value of `size` must be a positive integer.
Returns
-------
new_series : series
New instance of series with truncated coefficients.
"""
isize = int(size)
if isize != size or isize < 1:
raise ValueError("size must be a positive integer")
if isize >= len(self.coef):
coef = self.coef
else:
coef = self.coef[:isize]
return self.__class__(coef, self.domain, self.window)
def convert(self, domain=None, kind=None, window=None):
"""Convert series to a different kind and/or domain and/or window.
Parameters
----------
domain : array_like, optional
The domain of the converted series. If the value is None,
the default domain of `kind` is used.
kind : class, optional
The polynomial series type class to which the current instance
should be converted. If kind is None, then the class of the
current instance is used.
window : array_like, optional
The window of the converted series. If the value is None,
the default window of `kind` is used.
Returns
-------
new_series : series
The returned class can be of different type than the current
instance and/or have a different domain and/or different
window.
Notes
-----
Conversion between domains and class types can result in
numerically ill defined series.
Examples
--------
"""
if kind is None:
kind = self.__class__
if domain is None:
domain = kind.domain
if window is None:
window = kind.window
return self(kind.identity(domain, window=window))
def mapparms(self):
"""Return the mapping parameters.
The returned values define a linear map ``off + scl*x`` that is
applied to the input arguments before the series is evaluated. The
map depends on the ``domain`` and ``window``; if the current
``domain`` is equal to the ``window`` the resulting map is the
identity. If the coefficients of the series instance are to be
used by themselves outside this class, then the linear function
must be substituted for the ``x`` in the standard representation of
the base polynomials.
Returns
-------
off, scl : float or complex
The mapping function is defined by ``off + scl*x``.
Notes
-----
If the current domain is the interval ``[l1, r1]`` and the window
is ``[l2, r2]``, then the linear mapping function ``L`` is
defined by the equations::
L(l1) = l2
L(r1) = r2
"""
return pu.mapparms(self.domain, self.window)
def integ(self, m=1, k=[], lbnd=None):
"""Integrate.
Return a series instance that is the definite integral of the
current series.
Parameters
----------
m : non-negative int
The number of integrations to perform.
k : array_like
Integration constants. The first constant is applied to the
first integration, the second to the second, and so on. The
list of values must less than or equal to `m` in length and any
missing values are set to zero.
lbnd : Scalar
The lower bound of the definite integral.
Returns
-------
new_series : series
A new series representing the integral. The domain is the same
as the domain of the integrated series.
"""
off, scl = self.mapparms()
if lbnd is None:
lbnd = 0
else:
lbnd = off + scl*lbnd
coef = self._int(self.coef, m, k, lbnd, 1./scl)
return self.__class__(coef, self.domain, self.window)
def deriv(self, m=1):
"""Differentiate.
Return a series instance of that is the derivative of the current
series.
Parameters
----------
m : non-negative int
Find the derivative of order `m`.
Returns
-------
new_series : series
A new series representing the derivative. The domain is the same
as the domain of the differentiated series.
"""
off, scl = self.mapparms()
coef = self._der(self.coef, m, scl)
return self.__class__(coef, self.domain, self.window)
def roots(self):
"""Return the roots of the series polynomial.
Compute the roots for the series. Note that the accuracy of the
roots decrease the further outside the domain they lie.
Returns
-------
roots : ndarray
Array containing the roots of the series.
"""
roots = self._roots(self.coef)
return pu.mapdomain(roots, self.window, self.domain)
def linspace(self, n=100, domain=None):
"""Return x, y values at equally spaced points in domain.
Returns the x, y values at `n` linearly spaced points across the
domain. Here y is the value of the polynomial at the points x. By
default the domain is the same as that of the series instance.
This method is intended mostly as a plotting aid.
.. versionadded:: 1.5.0
Parameters
----------
n : int, optional
Number of point pairs to return. The default value is 100.
domain : {None, array_like}, optional
If not None, the specified domain is used instead of that of
the calling instance. It should be of the form ``[beg,end]``.
The default is None which case the class domain is used.
Returns
-------
x, y : ndarray
x is equal to linspace(self.domain[0], self.domain[1], n) and
y is the series evaluated at element of x.
"""
if domain is None:
domain = self.domain
x = np.linspace(domain[0], domain[1], n)
y = self(x)
return x, y
@classmethod
def fit(cls, x, y, deg, domain=None, rcond=None, full=False, w=None,
window=None):
"""Least squares fit to data.
Return a series instance that is the least squares fit to the data
`y` sampled at `x`. The domain of the returned instance can be
specified and this will often result in a superior fit with less
chance of ill conditioning.
Parameters
----------
x : array_like, shape (M,)
x-coordinates of the M sample points ``(x[i], y[i])``.
y : array_like, shape (M,) or (M, K)
y-coordinates of the sample points. Several data sets of sample
points sharing the same x-coordinates can be fitted at once by
passing in a 2D-array that contains one dataset per column.
deg : int or 1-D array_like
Degree(s) of the fitting polynomials. If `deg` is a single integer
all terms up to and including the `deg`'th term are included in the
fit. For NumPy versions >= 1.11.0 a list of integers specifying the
degrees of the terms to include may be used instead.
domain : {None, [beg, end], []}, optional
Domain to use for the returned series. If ``None``,
then a minimal domain that covers the points `x` is chosen. If
``[]`` the class domain is used. The default value was the
class domain in NumPy 1.4 and ``None`` in later versions.
The ``[]`` option was added in numpy 1.5.0.
rcond : float, optional
Relative condition number of the fit. Singular values smaller
than this relative to the largest singular value will be
ignored. The default value is len(x)*eps, where eps is the
relative precision of the float type, about 2e-16 in most
cases.
full : bool, optional
Switch determining nature of return value. When it is False
(the default) just the coefficients are returned, when True
diagnostic information from the singular value decomposition is
also returned.
w : array_like, shape (M,), optional
Weights. If not None the contribution of each point
``(x[i],y[i])`` to the fit is weighted by `w[i]`. Ideally the
weights are chosen so that the errors of the products
``w[i]*y[i]`` all have the same variance. The default value is
None.
.. versionadded:: 1.5.0
window : {[beg, end]}, optional
Window to use for the returned series. The default
value is the default class domain
.. versionadded:: 1.6.0
Returns
-------
new_series : series
A series that represents the least squares fit to the data and
has the domain specified in the call.
[resid, rank, sv, rcond] : list
These values are only returned if `full` = True
resid -- sum of squared residuals of the least squares fit
rank -- the numerical rank of the scaled Vandermonde matrix
sv -- singular values of the scaled Vandermonde matrix
rcond -- value of `rcond`.
For more details, see `linalg.lstsq`.
"""
if domain is None:
domain = pu.getdomain(x)
elif type(domain) is list and len(domain) == 0:
domain = cls.domain
if window is None:
window = cls.window
xnew = pu.mapdomain(x, domain, window)
res = cls._fit(xnew, y, deg, w=w, rcond=rcond, full=full)
if full:
[coef, status] = res
return cls(coef, domain=domain, window=window), status
else:
coef = res
return cls(coef, domain=domain, window=window)
@classmethod
def fromroots(cls, roots, domain=[], window=None):
"""Return series instance that has the specified roots.
Returns a series representing the product
``(x - r[0])*(x - r[1])*...*(x - r[n-1])``, where ``r`` is a
list of roots.
Parameters
----------
roots : array_like
List of roots.
domain : {[], None, array_like}, optional
Domain for the resulting series. If None the domain is the
interval from the smallest root to the largest. If [] the
domain is the class domain. The default is [].
window : {None, array_like}, optional
Window for the returned series. If None the class window is
used. The default is None.
Returns
-------
new_series : series
Series with the specified roots.
"""
[roots] = pu.as_series([roots], trim=False)
if domain is None:
domain = pu.getdomain(roots)
elif type(domain) is list and len(domain) == 0:
domain = cls.domain
if window is None:
window = cls.window
deg = len(roots)
off, scl = pu.mapparms(domain, window)
rnew = off + scl*roots
coef = cls._fromroots(rnew) / scl**deg
return cls(coef, domain=domain, window=window)
@classmethod
def identity(cls, domain=None, window=None):
"""Identity function.
If ``p`` is the returned series, then ``p(x) == x`` for all
values of x.
Parameters
----------
domain : {None, array_like}, optional
If given, the array must be of the form ``[beg, end]``, where
``beg`` and ``end`` are the endpoints of the domain. If None is
given then the class domain is used. The default is None.
window : {None, array_like}, optional
If given, the resulting array must be if the form
``[beg, end]``, where ``beg`` and ``end`` are the endpoints of
the window. If None is given then the class window is used. The
default is None.
Returns
-------
new_series : series
Series of representing the identity.
"""
if domain is None:
domain = cls.domain
if window is None:
window = cls.window
off, scl = pu.mapparms(window, domain)
coef = cls._line(off, scl)
return cls(coef, domain, window)
@classmethod
def basis(cls, deg, domain=None, window=None):
"""Series basis polynomial of degree `deg`.
Returns the series representing the basis polynomial of degree `deg`.
.. versionadded:: 1.7.0
Parameters
----------
deg : int
Degree of the basis polynomial for the series. Must be >= 0.
domain : {None, array_like}, optional
If given, the array must be of the form ``[beg, end]``, where
``beg`` and ``end`` are the endpoints of the domain. If None is
given then the class domain is used. The default is None.
window : {None, array_like}, optional
If given, the resulting array must be if the form
``[beg, end]``, where ``beg`` and ``end`` are the endpoints of
the window. If None is given then the class window is used. The
default is None.
Returns
-------
new_series : series
A series with the coefficient of the `deg` term set to one and
all others zero.
"""
if domain is None:
domain = cls.domain
if window is None:
window = cls.window
ideg = int(deg)
if ideg != deg or ideg < 0:
raise ValueError("deg must be non-negative integer")
return cls([0]*ideg + [1], domain, window)
@classmethod
def cast(cls, series, domain=None, window=None):
"""Convert series to series of this class.
The `series` is expected to be an instance of some polynomial
series of one of the types supported by by the numpy.polynomial
module, but could be some other class that supports the convert
method.
.. versionadded:: 1.7.0
Parameters
----------
series : series
The series instance to be converted.
domain : {None, array_like}, optional
If given, the array must be of the form ``[beg, end]``, where
``beg`` and ``end`` are the endpoints of the domain. If None is
given then the class domain is used. The default is None.
window : {None, array_like}, optional
If given, the resulting array must be if the form
``[beg, end]``, where ``beg`` and ``end`` are the endpoints of
the window. If None is given then the class window is used. The
default is None.
Returns
-------
new_series : series
A series of the same kind as the calling class and equal to
`series` when evaluated.
See Also
--------
convert : similar instance method
"""
if domain is None:
domain = cls.domain
if window is None:
window = cls.window
return series.convert(domain, cls, window)

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"""
Utility classes and functions for the polynomial modules.
This module provides: error and warning objects; a polynomial base class;
and some routines used in both the `polynomial` and `chebyshev` modules.
Error objects
-------------
.. autosummary::
:toctree: generated/
PolyError base class for this sub-package's errors.
PolyDomainError raised when domains are mismatched.
Warning objects
---------------
.. autosummary::
:toctree: generated/
RankWarning raised in least-squares fit for rank-deficient matrix.
Base class
----------
.. autosummary::
:toctree: generated/
PolyBase Obsolete base class for the polynomial classes. Do not use.
Functions
---------
.. autosummary::
:toctree: generated/
as_series convert list of array_likes into 1-D arrays of common type.
trimseq remove trailing zeros.
trimcoef remove small trailing coefficients.
getdomain return the domain appropriate for a given set of abscissae.
mapdomain maps points between domains.
mapparms parameters of the linear map between domains.
"""
from __future__ import division, absolute_import, print_function
import numpy as np
__all__ = [
'RankWarning', 'PolyError', 'PolyDomainError', 'as_series', 'trimseq',
'trimcoef', 'getdomain', 'mapdomain', 'mapparms', 'PolyBase']
#
# Warnings and Exceptions
#
class RankWarning(UserWarning):
"""Issued by chebfit when the design matrix is rank deficient."""
pass
class PolyError(Exception):
"""Base class for errors in this module."""
pass
class PolyDomainError(PolyError):
"""Issued by the generic Poly class when two domains don't match.
This is raised when an binary operation is passed Poly objects with
different domains.
"""
pass
#
# Base class for all polynomial types
#
class PolyBase(object):
"""
Base class for all polynomial types.
Deprecated in numpy 1.9.0, use the abstract
ABCPolyBase class instead. Note that the latter
requires a number of virtual functions to be
implemented.
"""
pass
#
# Helper functions to convert inputs to 1-D arrays
#
def trimseq(seq):
"""Remove small Poly series coefficients.
Parameters
----------
seq : sequence
Sequence of Poly series coefficients. This routine fails for
empty sequences.
Returns
-------
series : sequence
Subsequence with trailing zeros removed. If the resulting sequence
would be empty, return the first element. The returned sequence may
or may not be a view.
Notes
-----
Do not lose the type info if the sequence contains unknown objects.
"""
if len(seq) == 0:
return seq
else:
for i in range(len(seq) - 1, -1, -1):
if seq[i] != 0:
break
return seq[:i+1]
def as_series(alist, trim=True):
"""
Return argument as a list of 1-d arrays.
The returned list contains array(s) of dtype double, complex double, or
object. A 1-d argument of shape ``(N,)`` is parsed into ``N`` arrays of
size one; a 2-d argument of shape ``(M,N)`` is parsed into ``M`` arrays
of size ``N`` (i.e., is "parsed by row"); and a higher dimensional array
raises a Value Error if it is not first reshaped into either a 1-d or 2-d
array.
Parameters
----------
alist : array_like
A 1- or 2-d array_like
trim : boolean, optional
When True, trailing zeros are removed from the inputs.
When False, the inputs are passed through intact.
Returns
-------
[a1, a2,...] : list of 1-D arrays
A copy of the input data as a list of 1-d arrays.
Raises
------
ValueError
Raised when `as_series` cannot convert its input to 1-d arrays, or at
least one of the resulting arrays is empty.
Examples
--------
>>> from numpy.polynomial import polyutils as pu
>>> a = np.arange(4)
>>> pu.as_series(a)
[array([ 0.]), array([ 1.]), array([ 2.]), array([ 3.])]
>>> b = np.arange(6).reshape((2,3))
>>> pu.as_series(b)
[array([ 0., 1., 2.]), array([ 3., 4., 5.])]
>>> pu.as_series((1, np.arange(3), np.arange(2, dtype=np.float16)))
[array([ 1.]), array([ 0., 1., 2.]), array([ 0., 1.])]
>>> pu.as_series([2, [1.1, 0.]])
[array([ 2.]), array([ 1.1])]
>>> pu.as_series([2, [1.1, 0.]], trim=False)
[array([ 2.]), array([ 1.1, 0. ])]
"""
arrays = [np.array(a, ndmin=1, copy=0) for a in alist]
if min([a.size for a in arrays]) == 0:
raise ValueError("Coefficient array is empty")
if any([a.ndim != 1 for a in arrays]):
raise ValueError("Coefficient array is not 1-d")
if trim:
arrays = [trimseq(a) for a in arrays]
if any([a.dtype == np.dtype(object) for a in arrays]):
ret = []
for a in arrays:
if a.dtype != np.dtype(object):
tmp = np.empty(len(a), dtype=np.dtype(object))
tmp[:] = a[:]
ret.append(tmp)
else:
ret.append(a.copy())
else:
try:
dtype = np.common_type(*arrays)
except Exception:
raise ValueError("Coefficient arrays have no common type")
ret = [np.array(a, copy=1, dtype=dtype) for a in arrays]
return ret
def trimcoef(c, tol=0):
"""
Remove "small" "trailing" coefficients from a polynomial.
"Small" means "small in absolute value" and is controlled by the
parameter `tol`; "trailing" means highest order coefficient(s), e.g., in
``[0, 1, 1, 0, 0]`` (which represents ``0 + x + x**2 + 0*x**3 + 0*x**4``)
both the 3-rd and 4-th order coefficients would be "trimmed."
Parameters
----------
c : array_like
1-d array of coefficients, ordered from lowest order to highest.
tol : number, optional
Trailing (i.e., highest order) elements with absolute value less
than or equal to `tol` (default value is zero) are removed.
Returns
-------
trimmed : ndarray
1-d array with trailing zeros removed. If the resulting series
would be empty, a series containing a single zero is returned.
Raises
------
ValueError
If `tol` < 0
See Also
--------
trimseq
Examples
--------
>>> from numpy.polynomial import polyutils as pu
>>> pu.trimcoef((0,0,3,0,5,0,0))
array([ 0., 0., 3., 0., 5.])
>>> pu.trimcoef((0,0,1e-3,0,1e-5,0,0),1e-3) # item == tol is trimmed
array([ 0.])
>>> i = complex(0,1) # works for complex
>>> pu.trimcoef((3e-4,1e-3*(1-i),5e-4,2e-5*(1+i)), 1e-3)
array([ 0.0003+0.j , 0.0010-0.001j])
"""
if tol < 0:
raise ValueError("tol must be non-negative")
[c] = as_series([c])
[ind] = np.nonzero(np.abs(c) > tol)
if len(ind) == 0:
return c[:1]*0
else:
return c[:ind[-1] + 1].copy()
def getdomain(x):
"""
Return a domain suitable for given abscissae.
Find a domain suitable for a polynomial or Chebyshev series
defined at the values supplied.
Parameters
----------
x : array_like
1-d array of abscissae whose domain will be determined.
Returns
-------
domain : ndarray
1-d array containing two values. If the inputs are complex, then
the two returned points are the lower left and upper right corners
of the smallest rectangle (aligned with the axes) in the complex
plane containing the points `x`. If the inputs are real, then the
two points are the ends of the smallest interval containing the
points `x`.
See Also
--------
mapparms, mapdomain
Examples
--------
>>> from numpy.polynomial import polyutils as pu
>>> points = np.arange(4)**2 - 5; points
array([-5, -4, -1, 4])
>>> pu.getdomain(points)
array([-5., 4.])
>>> c = np.exp(complex(0,1)*np.pi*np.arange(12)/6) # unit circle
>>> pu.getdomain(c)
array([-1.-1.j, 1.+1.j])
"""
[x] = as_series([x], trim=False)
if x.dtype.char in np.typecodes['Complex']:
rmin, rmax = x.real.min(), x.real.max()
imin, imax = x.imag.min(), x.imag.max()
return np.array((complex(rmin, imin), complex(rmax, imax)))
else:
return np.array((x.min(), x.max()))
def mapparms(old, new):
"""
Linear map parameters between domains.
Return the parameters of the linear map ``offset + scale*x`` that maps
`old` to `new` such that ``old[i] -> new[i]``, ``i = 0, 1``.
Parameters
----------
old, new : array_like
Domains. Each domain must (successfully) convert to a 1-d array
containing precisely two values.
Returns
-------
offset, scale : scalars
The map ``L(x) = offset + scale*x`` maps the first domain to the
second.
See Also
--------
getdomain, mapdomain
Notes
-----
Also works for complex numbers, and thus can be used to calculate the
parameters required to map any line in the complex plane to any other
line therein.
Examples
--------
>>> from numpy.polynomial import polyutils as pu
>>> pu.mapparms((-1,1),(-1,1))
(0.0, 1.0)
>>> pu.mapparms((1,-1),(-1,1))
(0.0, -1.0)
>>> i = complex(0,1)
>>> pu.mapparms((-i,-1),(1,i))
((1+1j), (1+0j))
"""
oldlen = old[1] - old[0]
newlen = new[1] - new[0]
off = (old[1]*new[0] - old[0]*new[1])/oldlen
scl = newlen/oldlen
return off, scl
def mapdomain(x, old, new):
"""
Apply linear map to input points.
The linear map ``offset + scale*x`` that maps the domain `old` to
the domain `new` is applied to the points `x`.
Parameters
----------
x : array_like
Points to be mapped. If `x` is a subtype of ndarray the subtype
will be preserved.
old, new : array_like
The two domains that determine the map. Each must (successfully)
convert to 1-d arrays containing precisely two values.
Returns
-------
x_out : ndarray
Array of points of the same shape as `x`, after application of the
linear map between the two domains.
See Also
--------
getdomain, mapparms
Notes
-----
Effectively, this implements:
.. math ::
x\\_out = new[0] + m(x - old[0])
where
.. math ::
m = \\frac{new[1]-new[0]}{old[1]-old[0]}
Examples
--------
>>> from numpy.polynomial import polyutils as pu
>>> old_domain = (-1,1)
>>> new_domain = (0,2*np.pi)
>>> x = np.linspace(-1,1,6); x
array([-1. , -0.6, -0.2, 0.2, 0.6, 1. ])
>>> x_out = pu.mapdomain(x, old_domain, new_domain); x_out
array([ 0. , 1.25663706, 2.51327412, 3.76991118, 5.02654825,
6.28318531])
>>> x - pu.mapdomain(x_out, new_domain, old_domain)
array([ 0., 0., 0., 0., 0., 0.])
Also works for complex numbers (and thus can be used to map any line in
the complex plane to any other line therein).
>>> i = complex(0,1)
>>> old = (-1 - i, 1 + i)
>>> new = (-1 + i, 1 - i)
>>> z = np.linspace(old[0], old[1], 6); z
array([-1.0-1.j , -0.6-0.6j, -0.2-0.2j, 0.2+0.2j, 0.6+0.6j, 1.0+1.j ])
>>> new_z = P.mapdomain(z, old, new); new_z
array([-1.0+1.j , -0.6+0.6j, -0.2+0.2j, 0.2-0.2j, 0.6-0.6j, 1.0-1.j ])
"""
x = np.asanyarray(x)
off, scl = mapparms(old, new)
return off + scl*x

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from __future__ import division, print_function
def configuration(parent_package='',top_path=None):
from numpy.distutils.misc_util import Configuration
config = Configuration('polynomial', parent_package, top_path)
config.add_data_dir('tests')
return config
if __name__ == '__main__':
from numpy.distutils.core import setup
setup(configuration=configuration)

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"""Tests for chebyshev module.
"""
from __future__ import division, absolute_import, print_function
import numpy as np
import numpy.polynomial.chebyshev as cheb
from numpy.polynomial.polynomial import polyval
from numpy.testing import (
assert_almost_equal, assert_raises, assert_equal, assert_,
run_module_suite
)
def trim(x):
return cheb.chebtrim(x, tol=1e-6)
T0 = [1]
T1 = [0, 1]
T2 = [-1, 0, 2]
T3 = [0, -3, 0, 4]
T4 = [1, 0, -8, 0, 8]
T5 = [0, 5, 0, -20, 0, 16]
T6 = [-1, 0, 18, 0, -48, 0, 32]
T7 = [0, -7, 0, 56, 0, -112, 0, 64]
T8 = [1, 0, -32, 0, 160, 0, -256, 0, 128]
T9 = [0, 9, 0, -120, 0, 432, 0, -576, 0, 256]
Tlist = [T0, T1, T2, T3, T4, T5, T6, T7, T8, T9]
class TestPrivate(object):
def test__cseries_to_zseries(self):
for i in range(5):
inp = np.array([2] + [1]*i, np.double)
tgt = np.array([.5]*i + [2] + [.5]*i, np.double)
res = cheb._cseries_to_zseries(inp)
assert_equal(res, tgt)
def test__zseries_to_cseries(self):
for i in range(5):
inp = np.array([.5]*i + [2] + [.5]*i, np.double)
tgt = np.array([2] + [1]*i, np.double)
res = cheb._zseries_to_cseries(inp)
assert_equal(res, tgt)
class TestConstants(object):
def test_chebdomain(self):
assert_equal(cheb.chebdomain, [-1, 1])
def test_chebzero(self):
assert_equal(cheb.chebzero, [0])
def test_chebone(self):
assert_equal(cheb.chebone, [1])
def test_chebx(self):
assert_equal(cheb.chebx, [0, 1])
class TestArithmetic(object):
def test_chebadd(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] += 1
res = cheb.chebadd([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_chebsub(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] -= 1
res = cheb.chebsub([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_chebmulx(self):
assert_equal(cheb.chebmulx([0]), [0])
assert_equal(cheb.chebmulx([1]), [0, 1])
for i in range(1, 5):
ser = [0]*i + [1]
tgt = [0]*(i - 1) + [.5, 0, .5]
assert_equal(cheb.chebmulx(ser), tgt)
def test_chebmul(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(i + j + 1)
tgt[i + j] += .5
tgt[abs(i - j)] += .5
res = cheb.chebmul([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_chebdiv(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
ci = [0]*i + [1]
cj = [0]*j + [1]
tgt = cheb.chebadd(ci, cj)
quo, rem = cheb.chebdiv(tgt, ci)
res = cheb.chebadd(cheb.chebmul(quo, ci), rem)
assert_equal(trim(res), trim(tgt), err_msg=msg)
class TestEvaluation(object):
# coefficients of 1 + 2*x + 3*x**2
c1d = np.array([2.5, 2., 1.5])
c2d = np.einsum('i,j->ij', c1d, c1d)
c3d = np.einsum('i,j,k->ijk', c1d, c1d, c1d)
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
y = polyval(x, [1., 2., 3.])
def test_chebval(self):
#check empty input
assert_equal(cheb.chebval([], [1]).size, 0)
#check normal input)
x = np.linspace(-1, 1)
y = [polyval(x, c) for c in Tlist]
for i in range(10):
msg = "At i=%d" % i
tgt = y[i]
res = cheb.chebval(x, [0]*i + [1])
assert_almost_equal(res, tgt, err_msg=msg)
#check that shape is preserved
for i in range(3):
dims = [2]*i
x = np.zeros(dims)
assert_equal(cheb.chebval(x, [1]).shape, dims)
assert_equal(cheb.chebval(x, [1, 0]).shape, dims)
assert_equal(cheb.chebval(x, [1, 0, 0]).shape, dims)
def test_chebval2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, cheb.chebval2d, x1, x2[:2], self.c2d)
#test values
tgt = y1*y2
res = cheb.chebval2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = cheb.chebval2d(z, z, self.c2d)
assert_(res.shape == (2, 3))
def test_chebval3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, cheb.chebval3d, x1, x2, x3[:2], self.c3d)
#test values
tgt = y1*y2*y3
res = cheb.chebval3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = cheb.chebval3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3))
def test_chebgrid2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j->ij', y1, y2)
res = cheb.chebgrid2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = cheb.chebgrid2d(z, z, self.c2d)
assert_(res.shape == (2, 3)*2)
def test_chebgrid3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j,k->ijk', y1, y2, y3)
res = cheb.chebgrid3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = cheb.chebgrid3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3)*3)
class TestIntegral(object):
def test_chebint(self):
# check exceptions
assert_raises(ValueError, cheb.chebint, [0], .5)
assert_raises(ValueError, cheb.chebint, [0], -1)
assert_raises(ValueError, cheb.chebint, [0], 1, [0, 0])
assert_raises(ValueError, cheb.chebint, [0], lbnd=[0])
assert_raises(ValueError, cheb.chebint, [0], scl=[0])
assert_raises(ValueError, cheb.chebint, [0], axis=.5)
# test integration of zero polynomial
for i in range(2, 5):
k = [0]*(i - 2) + [1]
res = cheb.chebint([0], m=i, k=k)
assert_almost_equal(res, [0, 1])
# check single integration with integration constant
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [1/scl]
chebpol = cheb.poly2cheb(pol)
chebint = cheb.chebint(chebpol, m=1, k=[i])
res = cheb.cheb2poly(chebint)
assert_almost_equal(trim(res), trim(tgt))
# check single integration with integration constant and lbnd
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
chebpol = cheb.poly2cheb(pol)
chebint = cheb.chebint(chebpol, m=1, k=[i], lbnd=-1)
assert_almost_equal(cheb.chebval(-1, chebint), i)
# check single integration with integration constant and scaling
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [2/scl]
chebpol = cheb.poly2cheb(pol)
chebint = cheb.chebint(chebpol, m=1, k=[i], scl=2)
res = cheb.cheb2poly(chebint)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with default k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = cheb.chebint(tgt, m=1)
res = cheb.chebint(pol, m=j)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with defined k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = cheb.chebint(tgt, m=1, k=[k])
res = cheb.chebint(pol, m=j, k=list(range(j)))
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with lbnd
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = cheb.chebint(tgt, m=1, k=[k], lbnd=-1)
res = cheb.chebint(pol, m=j, k=list(range(j)), lbnd=-1)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with scaling
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = cheb.chebint(tgt, m=1, k=[k], scl=2)
res = cheb.chebint(pol, m=j, k=list(range(j)), scl=2)
assert_almost_equal(trim(res), trim(tgt))
def test_chebint_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([cheb.chebint(c) for c in c2d.T]).T
res = cheb.chebint(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([cheb.chebint(c) for c in c2d])
res = cheb.chebint(c2d, axis=1)
assert_almost_equal(res, tgt)
tgt = np.vstack([cheb.chebint(c, k=3) for c in c2d])
res = cheb.chebint(c2d, k=3, axis=1)
assert_almost_equal(res, tgt)
class TestDerivative(object):
def test_chebder(self):
# check exceptions
assert_raises(ValueError, cheb.chebder, [0], .5)
assert_raises(ValueError, cheb.chebder, [0], -1)
# check that zeroth derivative does nothing
for i in range(5):
tgt = [0]*i + [1]
res = cheb.chebder(tgt, m=0)
assert_equal(trim(res), trim(tgt))
# check that derivation is the inverse of integration
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = cheb.chebder(cheb.chebint(tgt, m=j), m=j)
assert_almost_equal(trim(res), trim(tgt))
# check derivation with scaling
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = cheb.chebder(cheb.chebint(tgt, m=j, scl=2), m=j, scl=.5)
assert_almost_equal(trim(res), trim(tgt))
def test_chebder_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([cheb.chebder(c) for c in c2d.T]).T
res = cheb.chebder(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([cheb.chebder(c) for c in c2d])
res = cheb.chebder(c2d, axis=1)
assert_almost_equal(res, tgt)
class TestVander(object):
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
def test_chebvander(self):
# check for 1d x
x = np.arange(3)
v = cheb.chebvander(x, 3)
assert_(v.shape == (3, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], cheb.chebval(x, coef))
# check for 2d x
x = np.array([[1, 2], [3, 4], [5, 6]])
v = cheb.chebvander(x, 3)
assert_(v.shape == (3, 2, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], cheb.chebval(x, coef))
def test_chebvander2d(self):
# also tests chebval2d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3))
van = cheb.chebvander2d(x1, x2, [1, 2])
tgt = cheb.chebval2d(x1, x2, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = cheb.chebvander2d([x1], [x2], [1, 2])
assert_(van.shape == (1, 5, 6))
def test_chebvander3d(self):
# also tests chebval3d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3, 4))
van = cheb.chebvander3d(x1, x2, x3, [1, 2, 3])
tgt = cheb.chebval3d(x1, x2, x3, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = cheb.chebvander3d([x1], [x2], [x3], [1, 2, 3])
assert_(van.shape == (1, 5, 24))
class TestFitting(object):
def test_chebfit(self):
def f(x):
return x*(x - 1)*(x - 2)
def f2(x):
return x**4 + x**2 + 1
# Test exceptions
assert_raises(ValueError, cheb.chebfit, [1], [1], -1)
assert_raises(TypeError, cheb.chebfit, [[1]], [1], 0)
assert_raises(TypeError, cheb.chebfit, [], [1], 0)
assert_raises(TypeError, cheb.chebfit, [1], [[[1]]], 0)
assert_raises(TypeError, cheb.chebfit, [1, 2], [1], 0)
assert_raises(TypeError, cheb.chebfit, [1], [1, 2], 0)
assert_raises(TypeError, cheb.chebfit, [1], [1], 0, w=[[1]])
assert_raises(TypeError, cheb.chebfit, [1], [1], 0, w=[1, 1])
assert_raises(ValueError, cheb.chebfit, [1], [1], [-1,])
assert_raises(ValueError, cheb.chebfit, [1], [1], [2, -1, 6])
assert_raises(TypeError, cheb.chebfit, [1], [1], [])
# Test fit
x = np.linspace(0, 2)
y = f(x)
#
coef3 = cheb.chebfit(x, y, 3)
assert_equal(len(coef3), 4)
assert_almost_equal(cheb.chebval(x, coef3), y)
coef3 = cheb.chebfit(x, y, [0, 1, 2, 3])
assert_equal(len(coef3), 4)
assert_almost_equal(cheb.chebval(x, coef3), y)
#
coef4 = cheb.chebfit(x, y, 4)
assert_equal(len(coef4), 5)
assert_almost_equal(cheb.chebval(x, coef4), y)
coef4 = cheb.chebfit(x, y, [0, 1, 2, 3, 4])
assert_equal(len(coef4), 5)
assert_almost_equal(cheb.chebval(x, coef4), y)
# check things still work if deg is not in strict increasing
coef4 = cheb.chebfit(x, y, [2, 3, 4, 1, 0])
assert_equal(len(coef4), 5)
assert_almost_equal(cheb.chebval(x, coef4), y)
#
coef2d = cheb.chebfit(x, np.array([y, y]).T, 3)
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
coef2d = cheb.chebfit(x, np.array([y, y]).T, [0, 1, 2, 3])
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
# test weighting
w = np.zeros_like(x)
yw = y.copy()
w[1::2] = 1
y[0::2] = 0
wcoef3 = cheb.chebfit(x, yw, 3, w=w)
assert_almost_equal(wcoef3, coef3)
wcoef3 = cheb.chebfit(x, yw, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef3, coef3)
#
wcoef2d = cheb.chebfit(x, np.array([yw, yw]).T, 3, w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
wcoef2d = cheb.chebfit(x, np.array([yw, yw]).T, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
# test scaling with complex values x points whose square
# is zero when summed.
x = [1, 1j, -1, -1j]
assert_almost_equal(cheb.chebfit(x, x, 1), [0, 1])
assert_almost_equal(cheb.chebfit(x, x, [0, 1]), [0, 1])
# test fitting only even polynomials
x = np.linspace(-1, 1)
y = f2(x)
coef1 = cheb.chebfit(x, y, 4)
assert_almost_equal(cheb.chebval(x, coef1), y)
coef2 = cheb.chebfit(x, y, [0, 2, 4])
assert_almost_equal(cheb.chebval(x, coef2), y)
assert_almost_equal(coef1, coef2)
class TestInterpolate(object):
def f(self, x):
return x * (x - 1) * (x - 2)
def test_raises(self):
assert_raises(ValueError, cheb.chebinterpolate, self.f, -1)
assert_raises(TypeError, cheb.chebinterpolate, self.f, 10.)
def test_dimensions(self):
for deg in range(1, 5):
assert_(cheb.chebinterpolate(self.f, deg).shape == (deg + 1,))
def test_approximation(self):
def powx(x, p):
return x**p
x = np.linspace(-1, 1, 10)
for deg in range(0, 10):
for p in range(0, deg + 1):
c = cheb.chebinterpolate(powx, deg, (p,))
assert_almost_equal(cheb.chebval(x, c), powx(x, p), decimal=12)
class TestCompanion(object):
def test_raises(self):
assert_raises(ValueError, cheb.chebcompanion, [])
assert_raises(ValueError, cheb.chebcompanion, [1])
def test_dimensions(self):
for i in range(1, 5):
coef = [0]*i + [1]
assert_(cheb.chebcompanion(coef).shape == (i, i))
def test_linear_root(self):
assert_(cheb.chebcompanion([1, 2])[0, 0] == -.5)
class TestGauss(object):
def test_100(self):
x, w = cheb.chebgauss(100)
# test orthogonality. Note that the results need to be normalized,
# otherwise the huge values that can arise from fast growing
# functions like Laguerre can be very confusing.
v = cheb.chebvander(x, 99)
vv = np.dot(v.T * w, v)
vd = 1/np.sqrt(vv.diagonal())
vv = vd[:, None] * vv * vd
assert_almost_equal(vv, np.eye(100))
# check that the integral of 1 is correct
tgt = np.pi
assert_almost_equal(w.sum(), tgt)
class TestMisc(object):
def test_chebfromroots(self):
res = cheb.chebfromroots([])
assert_almost_equal(trim(res), [1])
for i in range(1, 5):
roots = np.cos(np.linspace(-np.pi, 0, 2*i + 1)[1::2])
tgt = [0]*i + [1]
res = cheb.chebfromroots(roots)*2**(i-1)
assert_almost_equal(trim(res), trim(tgt))
def test_chebroots(self):
assert_almost_equal(cheb.chebroots([1]), [])
assert_almost_equal(cheb.chebroots([1, 2]), [-.5])
for i in range(2, 5):
tgt = np.linspace(-1, 1, i)
res = cheb.chebroots(cheb.chebfromroots(tgt))
assert_almost_equal(trim(res), trim(tgt))
def test_chebtrim(self):
coef = [2, -1, 1, 0]
# Test exceptions
assert_raises(ValueError, cheb.chebtrim, coef, -1)
# Test results
assert_equal(cheb.chebtrim(coef), coef[:-1])
assert_equal(cheb.chebtrim(coef, 1), coef[:-3])
assert_equal(cheb.chebtrim(coef, 2), [0])
def test_chebline(self):
assert_equal(cheb.chebline(3, 4), [3, 4])
def test_cheb2poly(self):
for i in range(10):
assert_almost_equal(cheb.cheb2poly([0]*i + [1]), Tlist[i])
def test_poly2cheb(self):
for i in range(10):
assert_almost_equal(cheb.poly2cheb(Tlist[i]), [0]*i + [1])
def test_weight(self):
x = np.linspace(-1, 1, 11)[1:-1]
tgt = 1./(np.sqrt(1 + x) * np.sqrt(1 - x))
res = cheb.chebweight(x)
assert_almost_equal(res, tgt)
def test_chebpts1(self):
#test exceptions
assert_raises(ValueError, cheb.chebpts1, 1.5)
assert_raises(ValueError, cheb.chebpts1, 0)
#test points
tgt = [0]
assert_almost_equal(cheb.chebpts1(1), tgt)
tgt = [-0.70710678118654746, 0.70710678118654746]
assert_almost_equal(cheb.chebpts1(2), tgt)
tgt = [-0.86602540378443871, 0, 0.86602540378443871]
assert_almost_equal(cheb.chebpts1(3), tgt)
tgt = [-0.9238795325, -0.3826834323, 0.3826834323, 0.9238795325]
assert_almost_equal(cheb.chebpts1(4), tgt)
def test_chebpts2(self):
#test exceptions
assert_raises(ValueError, cheb.chebpts2, 1.5)
assert_raises(ValueError, cheb.chebpts2, 1)
#test points
tgt = [-1, 1]
assert_almost_equal(cheb.chebpts2(2), tgt)
tgt = [-1, 0, 1]
assert_almost_equal(cheb.chebpts2(3), tgt)
tgt = [-1, -0.5, .5, 1]
assert_almost_equal(cheb.chebpts2(4), tgt)
tgt = [-1.0, -0.707106781187, 0, 0.707106781187, 1.0]
assert_almost_equal(cheb.chebpts2(5), tgt)
if __name__ == "__main__":
run_module_suite()

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"""Test inter-conversion of different polynomial classes.
This tests the convert and cast methods of all the polynomial classes.
"""
from __future__ import division, absolute_import, print_function
import operator as op
from numbers import Number
import numpy as np
from numpy.polynomial import (
Polynomial, Legendre, Chebyshev, Laguerre, Hermite, HermiteE)
from numpy.testing import (
assert_almost_equal, assert_raises, assert_equal, assert_,
run_module_suite)
from numpy.compat import long
classes = (
Polynomial, Legendre, Chebyshev, Laguerre,
Hermite, HermiteE)
def test_class_methods():
for Poly1 in classes:
for Poly2 in classes:
yield check_conversion, Poly1, Poly2
yield check_cast, Poly1, Poly2
for Poly in classes:
yield check_call, Poly
yield check_identity, Poly
yield check_basis, Poly
yield check_fromroots, Poly
yield check_fit, Poly
yield check_equal, Poly
yield check_not_equal, Poly
yield check_add, Poly
yield check_sub, Poly
yield check_mul, Poly
yield check_floordiv, Poly
yield check_truediv, Poly
yield check_mod, Poly
yield check_divmod, Poly
yield check_pow, Poly
yield check_integ, Poly
yield check_deriv, Poly
yield check_roots, Poly
yield check_linspace, Poly
yield check_mapparms, Poly
yield check_degree, Poly
yield check_copy, Poly
yield check_cutdeg, Poly
yield check_truncate, Poly
yield check_trim, Poly
yield check_ufunc_override, Poly
#
# helper functions
#
random = np.random.random
def assert_poly_almost_equal(p1, p2, msg=""):
try:
assert_(np.all(p1.domain == p2.domain))
assert_(np.all(p1.window == p2.window))
assert_almost_equal(p1.coef, p2.coef)
except AssertionError:
msg = "Result: %s\nTarget: %s", (p1, p2)
raise AssertionError(msg)
#
# conversion methods that depend on two classes
#
def check_conversion(Poly1, Poly2):
x = np.linspace(0, 1, 10)
coef = random((3,))
d1 = Poly1.domain + random((2,))*.25
w1 = Poly1.window + random((2,))*.25
p1 = Poly1(coef, domain=d1, window=w1)
d2 = Poly2.domain + random((2,))*.25
w2 = Poly2.window + random((2,))*.25
p2 = p1.convert(kind=Poly2, domain=d2, window=w2)
assert_almost_equal(p2.domain, d2)
assert_almost_equal(p2.window, w2)
assert_almost_equal(p2(x), p1(x))
def check_cast(Poly1, Poly2):
x = np.linspace(0, 1, 10)
coef = random((3,))
d1 = Poly1.domain + random((2,))*.25
w1 = Poly1.window + random((2,))*.25
p1 = Poly1(coef, domain=d1, window=w1)
d2 = Poly2.domain + random((2,))*.25
w2 = Poly2.window + random((2,))*.25
p2 = Poly2.cast(p1, domain=d2, window=w2)
assert_almost_equal(p2.domain, d2)
assert_almost_equal(p2.window, w2)
assert_almost_equal(p2(x), p1(x))
#
# methods that depend on one class
#
def check_identity(Poly):
d = Poly.domain + random((2,))*.25
w = Poly.window + random((2,))*.25
x = np.linspace(d[0], d[1], 11)
p = Poly.identity(domain=d, window=w)
assert_equal(p.domain, d)
assert_equal(p.window, w)
assert_almost_equal(p(x), x)
def check_basis(Poly):
d = Poly.domain + random((2,))*.25
w = Poly.window + random((2,))*.25
p = Poly.basis(5, domain=d, window=w)
assert_equal(p.domain, d)
assert_equal(p.window, w)
assert_equal(p.coef, [0]*5 + [1])
def check_fromroots(Poly):
# check that requested roots are zeros of a polynomial
# of correct degree, domain, and window.
d = Poly.domain + random((2,))*.25
w = Poly.window + random((2,))*.25
r = random((5,))
p1 = Poly.fromroots(r, domain=d, window=w)
assert_equal(p1.degree(), len(r))
assert_equal(p1.domain, d)
assert_equal(p1.window, w)
assert_almost_equal(p1(r), 0)
# check that polynomial is monic
pdom = Polynomial.domain
pwin = Polynomial.window
p2 = Polynomial.cast(p1, domain=pdom, window=pwin)
assert_almost_equal(p2.coef[-1], 1)
def check_fit(Poly):
def f(x):
return x*(x - 1)*(x - 2)
x = np.linspace(0, 3)
y = f(x)
# check default value of domain and window
p = Poly.fit(x, y, 3)
assert_almost_equal(p.domain, [0, 3])
assert_almost_equal(p(x), y)
assert_equal(p.degree(), 3)
# check with given domains and window
d = Poly.domain + random((2,))*.25
w = Poly.window + random((2,))*.25
p = Poly.fit(x, y, 3, domain=d, window=w)
assert_almost_equal(p(x), y)
assert_almost_equal(p.domain, d)
assert_almost_equal(p.window, w)
p = Poly.fit(x, y, [0, 1, 2, 3], domain=d, window=w)
assert_almost_equal(p(x), y)
assert_almost_equal(p.domain, d)
assert_almost_equal(p.window, w)
# check with class domain default
p = Poly.fit(x, y, 3, [])
assert_equal(p.domain, Poly.domain)
assert_equal(p.window, Poly.window)
p = Poly.fit(x, y, [0, 1, 2, 3], [])
assert_equal(p.domain, Poly.domain)
assert_equal(p.window, Poly.window)
# check that fit accepts weights.
w = np.zeros_like(x)
z = y + random(y.shape)*.25
w[::2] = 1
p1 = Poly.fit(x[::2], z[::2], 3)
p2 = Poly.fit(x, z, 3, w=w)
p3 = Poly.fit(x, z, [0, 1, 2, 3], w=w)
assert_almost_equal(p1(x), p2(x))
assert_almost_equal(p2(x), p3(x))
def check_equal(Poly):
p1 = Poly([1, 2, 3], domain=[0, 1], window=[2, 3])
p2 = Poly([1, 1, 1], domain=[0, 1], window=[2, 3])
p3 = Poly([1, 2, 3], domain=[1, 2], window=[2, 3])
p4 = Poly([1, 2, 3], domain=[0, 1], window=[1, 2])
assert_(p1 == p1)
assert_(not p1 == p2)
assert_(not p1 == p3)
assert_(not p1 == p4)
def check_not_equal(Poly):
p1 = Poly([1, 2, 3], domain=[0, 1], window=[2, 3])
p2 = Poly([1, 1, 1], domain=[0, 1], window=[2, 3])
p3 = Poly([1, 2, 3], domain=[1, 2], window=[2, 3])
p4 = Poly([1, 2, 3], domain=[0, 1], window=[1, 2])
assert_(not p1 != p1)
assert_(p1 != p2)
assert_(p1 != p3)
assert_(p1 != p4)
def check_add(Poly):
# This checks commutation, not numerical correctness
c1 = list(random((4,)) + .5)
c2 = list(random((3,)) + .5)
p1 = Poly(c1)
p2 = Poly(c2)
p3 = p1 + p2
assert_poly_almost_equal(p2 + p1, p3)
assert_poly_almost_equal(p1 + c2, p3)
assert_poly_almost_equal(c2 + p1, p3)
assert_poly_almost_equal(p1 + tuple(c2), p3)
assert_poly_almost_equal(tuple(c2) + p1, p3)
assert_poly_almost_equal(p1 + np.array(c2), p3)
assert_poly_almost_equal(np.array(c2) + p1, p3)
assert_raises(TypeError, op.add, p1, Poly([0], domain=Poly.domain + 1))
assert_raises(TypeError, op.add, p1, Poly([0], window=Poly.window + 1))
if Poly is Polynomial:
assert_raises(TypeError, op.add, p1, Chebyshev([0]))
else:
assert_raises(TypeError, op.add, p1, Polynomial([0]))
def check_sub(Poly):
# This checks commutation, not numerical correctness
c1 = list(random((4,)) + .5)
c2 = list(random((3,)) + .5)
p1 = Poly(c1)
p2 = Poly(c2)
p3 = p1 - p2
assert_poly_almost_equal(p2 - p1, -p3)
assert_poly_almost_equal(p1 - c2, p3)
assert_poly_almost_equal(c2 - p1, -p3)
assert_poly_almost_equal(p1 - tuple(c2), p3)
assert_poly_almost_equal(tuple(c2) - p1, -p3)
assert_poly_almost_equal(p1 - np.array(c2), p3)
assert_poly_almost_equal(np.array(c2) - p1, -p3)
assert_raises(TypeError, op.sub, p1, Poly([0], domain=Poly.domain + 1))
assert_raises(TypeError, op.sub, p1, Poly([0], window=Poly.window + 1))
if Poly is Polynomial:
assert_raises(TypeError, op.sub, p1, Chebyshev([0]))
else:
assert_raises(TypeError, op.sub, p1, Polynomial([0]))
def check_mul(Poly):
c1 = list(random((4,)) + .5)
c2 = list(random((3,)) + .5)
p1 = Poly(c1)
p2 = Poly(c2)
p3 = p1 * p2
assert_poly_almost_equal(p2 * p1, p3)
assert_poly_almost_equal(p1 * c2, p3)
assert_poly_almost_equal(c2 * p1, p3)
assert_poly_almost_equal(p1 * tuple(c2), p3)
assert_poly_almost_equal(tuple(c2) * p1, p3)
assert_poly_almost_equal(p1 * np.array(c2), p3)
assert_poly_almost_equal(np.array(c2) * p1, p3)
assert_poly_almost_equal(p1 * 2, p1 * Poly([2]))
assert_poly_almost_equal(2 * p1, p1 * Poly([2]))
assert_raises(TypeError, op.mul, p1, Poly([0], domain=Poly.domain + 1))
assert_raises(TypeError, op.mul, p1, Poly([0], window=Poly.window + 1))
if Poly is Polynomial:
assert_raises(TypeError, op.mul, p1, Chebyshev([0]))
else:
assert_raises(TypeError, op.mul, p1, Polynomial([0]))
def check_floordiv(Poly):
c1 = list(random((4,)) + .5)
c2 = list(random((3,)) + .5)
c3 = list(random((2,)) + .5)
p1 = Poly(c1)
p2 = Poly(c2)
p3 = Poly(c3)
p4 = p1 * p2 + p3
c4 = list(p4.coef)
assert_poly_almost_equal(p4 // p2, p1)
assert_poly_almost_equal(p4 // c2, p1)
assert_poly_almost_equal(c4 // p2, p1)
assert_poly_almost_equal(p4 // tuple(c2), p1)
assert_poly_almost_equal(tuple(c4) // p2, p1)
assert_poly_almost_equal(p4 // np.array(c2), p1)
assert_poly_almost_equal(np.array(c4) // p2, p1)
assert_poly_almost_equal(2 // p2, Poly([0]))
assert_poly_almost_equal(p2 // 2, 0.5*p2)
assert_raises(
TypeError, op.floordiv, p1, Poly([0], domain=Poly.domain + 1))
assert_raises(
TypeError, op.floordiv, p1, Poly([0], window=Poly.window + 1))
if Poly is Polynomial:
assert_raises(TypeError, op.floordiv, p1, Chebyshev([0]))
else:
assert_raises(TypeError, op.floordiv, p1, Polynomial([0]))
def check_truediv(Poly):
# true division is valid only if the denominator is a Number and
# not a python bool.
p1 = Poly([1,2,3])
p2 = p1 * 5
for stype in np.ScalarType:
if not issubclass(stype, Number) or issubclass(stype, bool):
continue
s = stype(5)
assert_poly_almost_equal(op.truediv(p2, s), p1)
assert_raises(TypeError, op.truediv, s, p2)
for stype in (int, long, float):
s = stype(5)
assert_poly_almost_equal(op.truediv(p2, s), p1)
assert_raises(TypeError, op.truediv, s, p2)
for stype in [complex]:
s = stype(5, 0)
assert_poly_almost_equal(op.truediv(p2, s), p1)
assert_raises(TypeError, op.truediv, s, p2)
for s in [tuple(), list(), dict(), bool(), np.array([1])]:
assert_raises(TypeError, op.truediv, p2, s)
assert_raises(TypeError, op.truediv, s, p2)
for ptype in classes:
assert_raises(TypeError, op.truediv, p2, ptype(1))
def check_mod(Poly):
# This checks commutation, not numerical correctness
c1 = list(random((4,)) + .5)
c2 = list(random((3,)) + .5)
c3 = list(random((2,)) + .5)
p1 = Poly(c1)
p2 = Poly(c2)
p3 = Poly(c3)
p4 = p1 * p2 + p3
c4 = list(p4.coef)
assert_poly_almost_equal(p4 % p2, p3)
assert_poly_almost_equal(p4 % c2, p3)
assert_poly_almost_equal(c4 % p2, p3)
assert_poly_almost_equal(p4 % tuple(c2), p3)
assert_poly_almost_equal(tuple(c4) % p2, p3)
assert_poly_almost_equal(p4 % np.array(c2), p3)
assert_poly_almost_equal(np.array(c4) % p2, p3)
assert_poly_almost_equal(2 % p2, Poly([2]))
assert_poly_almost_equal(p2 % 2, Poly([0]))
assert_raises(TypeError, op.mod, p1, Poly([0], domain=Poly.domain + 1))
assert_raises(TypeError, op.mod, p1, Poly([0], window=Poly.window + 1))
if Poly is Polynomial:
assert_raises(TypeError, op.mod, p1, Chebyshev([0]))
else:
assert_raises(TypeError, op.mod, p1, Polynomial([0]))
def check_divmod(Poly):
# This checks commutation, not numerical correctness
c1 = list(random((4,)) + .5)
c2 = list(random((3,)) + .5)
c3 = list(random((2,)) + .5)
p1 = Poly(c1)
p2 = Poly(c2)
p3 = Poly(c3)
p4 = p1 * p2 + p3
c4 = list(p4.coef)
quo, rem = divmod(p4, p2)
assert_poly_almost_equal(quo, p1)
assert_poly_almost_equal(rem, p3)
quo, rem = divmod(p4, c2)
assert_poly_almost_equal(quo, p1)
assert_poly_almost_equal(rem, p3)
quo, rem = divmod(c4, p2)
assert_poly_almost_equal(quo, p1)
assert_poly_almost_equal(rem, p3)
quo, rem = divmod(p4, tuple(c2))
assert_poly_almost_equal(quo, p1)
assert_poly_almost_equal(rem, p3)
quo, rem = divmod(tuple(c4), p2)
assert_poly_almost_equal(quo, p1)
assert_poly_almost_equal(rem, p3)
quo, rem = divmod(p4, np.array(c2))
assert_poly_almost_equal(quo, p1)
assert_poly_almost_equal(rem, p3)
quo, rem = divmod(np.array(c4), p2)
assert_poly_almost_equal(quo, p1)
assert_poly_almost_equal(rem, p3)
quo, rem = divmod(p2, 2)
assert_poly_almost_equal(quo, 0.5*p2)
assert_poly_almost_equal(rem, Poly([0]))
quo, rem = divmod(2, p2)
assert_poly_almost_equal(quo, Poly([0]))
assert_poly_almost_equal(rem, Poly([2]))
assert_raises(TypeError, divmod, p1, Poly([0], domain=Poly.domain + 1))
assert_raises(TypeError, divmod, p1, Poly([0], window=Poly.window + 1))
if Poly is Polynomial:
assert_raises(TypeError, divmod, p1, Chebyshev([0]))
else:
assert_raises(TypeError, divmod, p1, Polynomial([0]))
def check_roots(Poly):
d = Poly.domain + random((2,))*.25
w = Poly.window + random((2,))*.25
tgt = np.sort(random((5,)))
res = np.sort(Poly.fromroots(tgt, domain=d, window=w).roots())
assert_almost_equal(res, tgt)
# default domain and window
res = np.sort(Poly.fromroots(tgt).roots())
assert_almost_equal(res, tgt)
def check_degree(Poly):
p = Poly.basis(5)
assert_equal(p.degree(), 5)
def check_copy(Poly):
p1 = Poly.basis(5)
p2 = p1.copy()
assert_(p1 == p2)
assert_(p1 is not p2)
assert_(p1.coef is not p2.coef)
assert_(p1.domain is not p2.domain)
assert_(p1.window is not p2.window)
def check_integ(Poly):
P = Polynomial
# Check defaults
p0 = Poly.cast(P([1*2, 2*3, 3*4]))
p1 = P.cast(p0.integ())
p2 = P.cast(p0.integ(2))
assert_poly_almost_equal(p1, P([0, 2, 3, 4]))
assert_poly_almost_equal(p2, P([0, 0, 1, 1, 1]))
# Check with k
p0 = Poly.cast(P([1*2, 2*3, 3*4]))
p1 = P.cast(p0.integ(k=1))
p2 = P.cast(p0.integ(2, k=[1, 1]))
assert_poly_almost_equal(p1, P([1, 2, 3, 4]))
assert_poly_almost_equal(p2, P([1, 1, 1, 1, 1]))
# Check with lbnd
p0 = Poly.cast(P([1*2, 2*3, 3*4]))
p1 = P.cast(p0.integ(lbnd=1))
p2 = P.cast(p0.integ(2, lbnd=1))
assert_poly_almost_equal(p1, P([-9, 2, 3, 4]))
assert_poly_almost_equal(p2, P([6, -9, 1, 1, 1]))
# Check scaling
d = 2*Poly.domain
p0 = Poly.cast(P([1*2, 2*3, 3*4]), domain=d)
p1 = P.cast(p0.integ())
p2 = P.cast(p0.integ(2))
assert_poly_almost_equal(p1, P([0, 2, 3, 4]))
assert_poly_almost_equal(p2, P([0, 0, 1, 1, 1]))
def check_deriv(Poly):
# Check that the derivative is the inverse of integration. It is
# assumes that the integration has been checked elsewhere.
d = Poly.domain + random((2,))*.25
w = Poly.window + random((2,))*.25
p1 = Poly([1, 2, 3], domain=d, window=w)
p2 = p1.integ(2, k=[1, 2])
p3 = p1.integ(1, k=[1])
assert_almost_equal(p2.deriv(1).coef, p3.coef)
assert_almost_equal(p2.deriv(2).coef, p1.coef)
# default domain and window
p1 = Poly([1, 2, 3])
p2 = p1.integ(2, k=[1, 2])
p3 = p1.integ(1, k=[1])
assert_almost_equal(p2.deriv(1).coef, p3.coef)
assert_almost_equal(p2.deriv(2).coef, p1.coef)
def check_linspace(Poly):
d = Poly.domain + random((2,))*.25
w = Poly.window + random((2,))*.25
p = Poly([1, 2, 3], domain=d, window=w)
# check default domain
xtgt = np.linspace(d[0], d[1], 20)
ytgt = p(xtgt)
xres, yres = p.linspace(20)
assert_almost_equal(xres, xtgt)
assert_almost_equal(yres, ytgt)
# check specified domain
xtgt = np.linspace(0, 2, 20)
ytgt = p(xtgt)
xres, yres = p.linspace(20, domain=[0, 2])
assert_almost_equal(xres, xtgt)
assert_almost_equal(yres, ytgt)
def check_pow(Poly):
d = Poly.domain + random((2,))*.25
w = Poly.window + random((2,))*.25
tgt = Poly([1], domain=d, window=w)
tst = Poly([1, 2, 3], domain=d, window=w)
for i in range(5):
assert_poly_almost_equal(tst**i, tgt)
tgt = tgt * tst
# default domain and window
tgt = Poly([1])
tst = Poly([1, 2, 3])
for i in range(5):
assert_poly_almost_equal(tst**i, tgt)
tgt = tgt * tst
# check error for invalid powers
assert_raises(ValueError, op.pow, tgt, 1.5)
assert_raises(ValueError, op.pow, tgt, -1)
def check_call(Poly):
P = Polynomial
d = Poly.domain
x = np.linspace(d[0], d[1], 11)
# Check defaults
p = Poly.cast(P([1, 2, 3]))
tgt = 1 + x*(2 + 3*x)
res = p(x)
assert_almost_equal(res, tgt)
def check_cutdeg(Poly):
p = Poly([1, 2, 3])
assert_raises(ValueError, p.cutdeg, .5)
assert_raises(ValueError, p.cutdeg, -1)
assert_equal(len(p.cutdeg(3)), 3)
assert_equal(len(p.cutdeg(2)), 3)
assert_equal(len(p.cutdeg(1)), 2)
assert_equal(len(p.cutdeg(0)), 1)
def check_truncate(Poly):
p = Poly([1, 2, 3])
assert_raises(ValueError, p.truncate, .5)
assert_raises(ValueError, p.truncate, 0)
assert_equal(len(p.truncate(4)), 3)
assert_equal(len(p.truncate(3)), 3)
assert_equal(len(p.truncate(2)), 2)
assert_equal(len(p.truncate(1)), 1)
def check_trim(Poly):
c = [1, 1e-6, 1e-12, 0]
p = Poly(c)
assert_equal(p.trim().coef, c[:3])
assert_equal(p.trim(1e-10).coef, c[:2])
assert_equal(p.trim(1e-5).coef, c[:1])
def check_mapparms(Poly):
# check with defaults. Should be identity.
d = Poly.domain
w = Poly.window
p = Poly([1], domain=d, window=w)
assert_almost_equal([0, 1], p.mapparms())
#
w = 2*d + 1
p = Poly([1], domain=d, window=w)
assert_almost_equal([1, 2], p.mapparms())
def check_ufunc_override(Poly):
p = Poly([1, 2, 3])
x = np.ones(3)
assert_raises(TypeError, np.add, p, x)
assert_raises(TypeError, np.add, x, p)
class TestInterpolate(object):
def f(self, x):
return x * (x - 1) * (x - 2)
def test_raises(self):
assert_raises(ValueError, Chebyshev.interpolate, self.f, -1)
assert_raises(TypeError, Chebyshev.interpolate, self.f, 10.)
def test_dimensions(self):
for deg in range(1, 5):
assert_(Chebyshev.interpolate(self.f, deg).degree() == deg)
def test_approximation(self):
def powx(x, p):
return x**p
x = np.linspace(0, 2, 10)
for deg in range(0, 10):
for t in range(0, deg + 1):
p = Chebyshev.interpolate(powx, deg, domain=[0, 2], args=(t,))
assert_almost_equal(p(x), powx(x, t), decimal=12)
if __name__ == "__main__":
run_module_suite()

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"""Tests for hermite module.
"""
from __future__ import division, absolute_import, print_function
import numpy as np
import numpy.polynomial.hermite as herm
from numpy.polynomial.polynomial import polyval
from numpy.testing import (
assert_almost_equal, assert_raises, assert_equal, assert_,
run_module_suite
)
H0 = np.array([1])
H1 = np.array([0, 2])
H2 = np.array([-2, 0, 4])
H3 = np.array([0, -12, 0, 8])
H4 = np.array([12, 0, -48, 0, 16])
H5 = np.array([0, 120, 0, -160, 0, 32])
H6 = np.array([-120, 0, 720, 0, -480, 0, 64])
H7 = np.array([0, -1680, 0, 3360, 0, -1344, 0, 128])
H8 = np.array([1680, 0, -13440, 0, 13440, 0, -3584, 0, 256])
H9 = np.array([0, 30240, 0, -80640, 0, 48384, 0, -9216, 0, 512])
Hlist = [H0, H1, H2, H3, H4, H5, H6, H7, H8, H9]
def trim(x):
return herm.hermtrim(x, tol=1e-6)
class TestConstants(object):
def test_hermdomain(self):
assert_equal(herm.hermdomain, [-1, 1])
def test_hermzero(self):
assert_equal(herm.hermzero, [0])
def test_hermone(self):
assert_equal(herm.hermone, [1])
def test_hermx(self):
assert_equal(herm.hermx, [0, .5])
class TestArithmetic(object):
x = np.linspace(-3, 3, 100)
def test_hermadd(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] += 1
res = herm.hermadd([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_hermsub(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] -= 1
res = herm.hermsub([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_hermmulx(self):
assert_equal(herm.hermmulx([0]), [0])
assert_equal(herm.hermmulx([1]), [0, .5])
for i in range(1, 5):
ser = [0]*i + [1]
tgt = [0]*(i - 1) + [i, 0, .5]
assert_equal(herm.hermmulx(ser), tgt)
def test_hermmul(self):
# check values of result
for i in range(5):
pol1 = [0]*i + [1]
val1 = herm.hermval(self.x, pol1)
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
pol2 = [0]*j + [1]
val2 = herm.hermval(self.x, pol2)
pol3 = herm.hermmul(pol1, pol2)
val3 = herm.hermval(self.x, pol3)
assert_(len(pol3) == i + j + 1, msg)
assert_almost_equal(val3, val1*val2, err_msg=msg)
def test_hermdiv(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
ci = [0]*i + [1]
cj = [0]*j + [1]
tgt = herm.hermadd(ci, cj)
quo, rem = herm.hermdiv(tgt, ci)
res = herm.hermadd(herm.hermmul(quo, ci), rem)
assert_equal(trim(res), trim(tgt), err_msg=msg)
class TestEvaluation(object):
# coefficients of 1 + 2*x + 3*x**2
c1d = np.array([2.5, 1., .75])
c2d = np.einsum('i,j->ij', c1d, c1d)
c3d = np.einsum('i,j,k->ijk', c1d, c1d, c1d)
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
y = polyval(x, [1., 2., 3.])
def test_hermval(self):
#check empty input
assert_equal(herm.hermval([], [1]).size, 0)
#check normal input)
x = np.linspace(-1, 1)
y = [polyval(x, c) for c in Hlist]
for i in range(10):
msg = "At i=%d" % i
tgt = y[i]
res = herm.hermval(x, [0]*i + [1])
assert_almost_equal(res, tgt, err_msg=msg)
#check that shape is preserved
for i in range(3):
dims = [2]*i
x = np.zeros(dims)
assert_equal(herm.hermval(x, [1]).shape, dims)
assert_equal(herm.hermval(x, [1, 0]).shape, dims)
assert_equal(herm.hermval(x, [1, 0, 0]).shape, dims)
def test_hermval2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, herm.hermval2d, x1, x2[:2], self.c2d)
#test values
tgt = y1*y2
res = herm.hermval2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = herm.hermval2d(z, z, self.c2d)
assert_(res.shape == (2, 3))
def test_hermval3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, herm.hermval3d, x1, x2, x3[:2], self.c3d)
#test values
tgt = y1*y2*y3
res = herm.hermval3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = herm.hermval3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3))
def test_hermgrid2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j->ij', y1, y2)
res = herm.hermgrid2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = herm.hermgrid2d(z, z, self.c2d)
assert_(res.shape == (2, 3)*2)
def test_hermgrid3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j,k->ijk', y1, y2, y3)
res = herm.hermgrid3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = herm.hermgrid3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3)*3)
class TestIntegral(object):
def test_hermint(self):
# check exceptions
assert_raises(ValueError, herm.hermint, [0], .5)
assert_raises(ValueError, herm.hermint, [0], -1)
assert_raises(ValueError, herm.hermint, [0], 1, [0, 0])
assert_raises(ValueError, herm.hermint, [0], lbnd=[0])
assert_raises(ValueError, herm.hermint, [0], scl=[0])
assert_raises(ValueError, herm.hermint, [0], axis=.5)
# test integration of zero polynomial
for i in range(2, 5):
k = [0]*(i - 2) + [1]
res = herm.hermint([0], m=i, k=k)
assert_almost_equal(res, [0, .5])
# check single integration with integration constant
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [1/scl]
hermpol = herm.poly2herm(pol)
hermint = herm.hermint(hermpol, m=1, k=[i])
res = herm.herm2poly(hermint)
assert_almost_equal(trim(res), trim(tgt))
# check single integration with integration constant and lbnd
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
hermpol = herm.poly2herm(pol)
hermint = herm.hermint(hermpol, m=1, k=[i], lbnd=-1)
assert_almost_equal(herm.hermval(-1, hermint), i)
# check single integration with integration constant and scaling
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [2/scl]
hermpol = herm.poly2herm(pol)
hermint = herm.hermint(hermpol, m=1, k=[i], scl=2)
res = herm.herm2poly(hermint)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with default k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = herm.hermint(tgt, m=1)
res = herm.hermint(pol, m=j)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with defined k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = herm.hermint(tgt, m=1, k=[k])
res = herm.hermint(pol, m=j, k=list(range(j)))
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with lbnd
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = herm.hermint(tgt, m=1, k=[k], lbnd=-1)
res = herm.hermint(pol, m=j, k=list(range(j)), lbnd=-1)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with scaling
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = herm.hermint(tgt, m=1, k=[k], scl=2)
res = herm.hermint(pol, m=j, k=list(range(j)), scl=2)
assert_almost_equal(trim(res), trim(tgt))
def test_hermint_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([herm.hermint(c) for c in c2d.T]).T
res = herm.hermint(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([herm.hermint(c) for c in c2d])
res = herm.hermint(c2d, axis=1)
assert_almost_equal(res, tgt)
tgt = np.vstack([herm.hermint(c, k=3) for c in c2d])
res = herm.hermint(c2d, k=3, axis=1)
assert_almost_equal(res, tgt)
class TestDerivative(object):
def test_hermder(self):
# check exceptions
assert_raises(ValueError, herm.hermder, [0], .5)
assert_raises(ValueError, herm.hermder, [0], -1)
# check that zeroth derivative does nothing
for i in range(5):
tgt = [0]*i + [1]
res = herm.hermder(tgt, m=0)
assert_equal(trim(res), trim(tgt))
# check that derivation is the inverse of integration
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = herm.hermder(herm.hermint(tgt, m=j), m=j)
assert_almost_equal(trim(res), trim(tgt))
# check derivation with scaling
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = herm.hermder(herm.hermint(tgt, m=j, scl=2), m=j, scl=.5)
assert_almost_equal(trim(res), trim(tgt))
def test_hermder_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([herm.hermder(c) for c in c2d.T]).T
res = herm.hermder(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([herm.hermder(c) for c in c2d])
res = herm.hermder(c2d, axis=1)
assert_almost_equal(res, tgt)
class TestVander(object):
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
def test_hermvander(self):
# check for 1d x
x = np.arange(3)
v = herm.hermvander(x, 3)
assert_(v.shape == (3, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], herm.hermval(x, coef))
# check for 2d x
x = np.array([[1, 2], [3, 4], [5, 6]])
v = herm.hermvander(x, 3)
assert_(v.shape == (3, 2, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], herm.hermval(x, coef))
def test_hermvander2d(self):
# also tests hermval2d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3))
van = herm.hermvander2d(x1, x2, [1, 2])
tgt = herm.hermval2d(x1, x2, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = herm.hermvander2d([x1], [x2], [1, 2])
assert_(van.shape == (1, 5, 6))
def test_hermvander3d(self):
# also tests hermval3d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3, 4))
van = herm.hermvander3d(x1, x2, x3, [1, 2, 3])
tgt = herm.hermval3d(x1, x2, x3, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = herm.hermvander3d([x1], [x2], [x3], [1, 2, 3])
assert_(van.shape == (1, 5, 24))
class TestFitting(object):
def test_hermfit(self):
def f(x):
return x*(x - 1)*(x - 2)
def f2(x):
return x**4 + x**2 + 1
# Test exceptions
assert_raises(ValueError, herm.hermfit, [1], [1], -1)
assert_raises(TypeError, herm.hermfit, [[1]], [1], 0)
assert_raises(TypeError, herm.hermfit, [], [1], 0)
assert_raises(TypeError, herm.hermfit, [1], [[[1]]], 0)
assert_raises(TypeError, herm.hermfit, [1, 2], [1], 0)
assert_raises(TypeError, herm.hermfit, [1], [1, 2], 0)
assert_raises(TypeError, herm.hermfit, [1], [1], 0, w=[[1]])
assert_raises(TypeError, herm.hermfit, [1], [1], 0, w=[1, 1])
assert_raises(ValueError, herm.hermfit, [1], [1], [-1,])
assert_raises(ValueError, herm.hermfit, [1], [1], [2, -1, 6])
assert_raises(TypeError, herm.hermfit, [1], [1], [])
# Test fit
x = np.linspace(0, 2)
y = f(x)
#
coef3 = herm.hermfit(x, y, 3)
assert_equal(len(coef3), 4)
assert_almost_equal(herm.hermval(x, coef3), y)
coef3 = herm.hermfit(x, y, [0, 1, 2, 3])
assert_equal(len(coef3), 4)
assert_almost_equal(herm.hermval(x, coef3), y)
#
coef4 = herm.hermfit(x, y, 4)
assert_equal(len(coef4), 5)
assert_almost_equal(herm.hermval(x, coef4), y)
coef4 = herm.hermfit(x, y, [0, 1, 2, 3, 4])
assert_equal(len(coef4), 5)
assert_almost_equal(herm.hermval(x, coef4), y)
# check things still work if deg is not in strict increasing
coef4 = herm.hermfit(x, y, [2, 3, 4, 1, 0])
assert_equal(len(coef4), 5)
assert_almost_equal(herm.hermval(x, coef4), y)
#
coef2d = herm.hermfit(x, np.array([y, y]).T, 3)
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
coef2d = herm.hermfit(x, np.array([y, y]).T, [0, 1, 2, 3])
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
# test weighting
w = np.zeros_like(x)
yw = y.copy()
w[1::2] = 1
y[0::2] = 0
wcoef3 = herm.hermfit(x, yw, 3, w=w)
assert_almost_equal(wcoef3, coef3)
wcoef3 = herm.hermfit(x, yw, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef3, coef3)
#
wcoef2d = herm.hermfit(x, np.array([yw, yw]).T, 3, w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
wcoef2d = herm.hermfit(x, np.array([yw, yw]).T, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
# test scaling with complex values x points whose square
# is zero when summed.
x = [1, 1j, -1, -1j]
assert_almost_equal(herm.hermfit(x, x, 1), [0, .5])
assert_almost_equal(herm.hermfit(x, x, [0, 1]), [0, .5])
# test fitting only even Legendre polynomials
x = np.linspace(-1, 1)
y = f2(x)
coef1 = herm.hermfit(x, y, 4)
assert_almost_equal(herm.hermval(x, coef1), y)
coef2 = herm.hermfit(x, y, [0, 2, 4])
assert_almost_equal(herm.hermval(x, coef2), y)
assert_almost_equal(coef1, coef2)
class TestCompanion(object):
def test_raises(self):
assert_raises(ValueError, herm.hermcompanion, [])
assert_raises(ValueError, herm.hermcompanion, [1])
def test_dimensions(self):
for i in range(1, 5):
coef = [0]*i + [1]
assert_(herm.hermcompanion(coef).shape == (i, i))
def test_linear_root(self):
assert_(herm.hermcompanion([1, 2])[0, 0] == -.25)
class TestGauss(object):
def test_100(self):
x, w = herm.hermgauss(100)
# test orthogonality. Note that the results need to be normalized,
# otherwise the huge values that can arise from fast growing
# functions like Laguerre can be very confusing.
v = herm.hermvander(x, 99)
vv = np.dot(v.T * w, v)
vd = 1/np.sqrt(vv.diagonal())
vv = vd[:, None] * vv * vd
assert_almost_equal(vv, np.eye(100))
# check that the integral of 1 is correct
tgt = np.sqrt(np.pi)
assert_almost_equal(w.sum(), tgt)
class TestMisc(object):
def test_hermfromroots(self):
res = herm.hermfromroots([])
assert_almost_equal(trim(res), [1])
for i in range(1, 5):
roots = np.cos(np.linspace(-np.pi, 0, 2*i + 1)[1::2])
pol = herm.hermfromroots(roots)
res = herm.hermval(roots, pol)
tgt = 0
assert_(len(pol) == i + 1)
assert_almost_equal(herm.herm2poly(pol)[-1], 1)
assert_almost_equal(res, tgt)
def test_hermroots(self):
assert_almost_equal(herm.hermroots([1]), [])
assert_almost_equal(herm.hermroots([1, 1]), [-.5])
for i in range(2, 5):
tgt = np.linspace(-1, 1, i)
res = herm.hermroots(herm.hermfromroots(tgt))
assert_almost_equal(trim(res), trim(tgt))
def test_hermtrim(self):
coef = [2, -1, 1, 0]
# Test exceptions
assert_raises(ValueError, herm.hermtrim, coef, -1)
# Test results
assert_equal(herm.hermtrim(coef), coef[:-1])
assert_equal(herm.hermtrim(coef, 1), coef[:-3])
assert_equal(herm.hermtrim(coef, 2), [0])
def test_hermline(self):
assert_equal(herm.hermline(3, 4), [3, 2])
def test_herm2poly(self):
for i in range(10):
assert_almost_equal(herm.herm2poly([0]*i + [1]), Hlist[i])
def test_poly2herm(self):
for i in range(10):
assert_almost_equal(herm.poly2herm(Hlist[i]), [0]*i + [1])
def test_weight(self):
x = np.linspace(-5, 5, 11)
tgt = np.exp(-x**2)
res = herm.hermweight(x)
assert_almost_equal(res, tgt)
if __name__ == "__main__":
run_module_suite()

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"""Tests for hermite_e module.
"""
from __future__ import division, absolute_import, print_function
import numpy as np
import numpy.polynomial.hermite_e as herme
from numpy.polynomial.polynomial import polyval
from numpy.testing import (
assert_almost_equal, assert_raises, assert_equal, assert_,
run_module_suite
)
He0 = np.array([1])
He1 = np.array([0, 1])
He2 = np.array([-1, 0, 1])
He3 = np.array([0, -3, 0, 1])
He4 = np.array([3, 0, -6, 0, 1])
He5 = np.array([0, 15, 0, -10, 0, 1])
He6 = np.array([-15, 0, 45, 0, -15, 0, 1])
He7 = np.array([0, -105, 0, 105, 0, -21, 0, 1])
He8 = np.array([105, 0, -420, 0, 210, 0, -28, 0, 1])
He9 = np.array([0, 945, 0, -1260, 0, 378, 0, -36, 0, 1])
Helist = [He0, He1, He2, He3, He4, He5, He6, He7, He8, He9]
def trim(x):
return herme.hermetrim(x, tol=1e-6)
class TestConstants(object):
def test_hermedomain(self):
assert_equal(herme.hermedomain, [-1, 1])
def test_hermezero(self):
assert_equal(herme.hermezero, [0])
def test_hermeone(self):
assert_equal(herme.hermeone, [1])
def test_hermex(self):
assert_equal(herme.hermex, [0, 1])
class TestArithmetic(object):
x = np.linspace(-3, 3, 100)
def test_hermeadd(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] += 1
res = herme.hermeadd([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_hermesub(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] -= 1
res = herme.hermesub([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_hermemulx(self):
assert_equal(herme.hermemulx([0]), [0])
assert_equal(herme.hermemulx([1]), [0, 1])
for i in range(1, 5):
ser = [0]*i + [1]
tgt = [0]*(i - 1) + [i, 0, 1]
assert_equal(herme.hermemulx(ser), tgt)
def test_hermemul(self):
# check values of result
for i in range(5):
pol1 = [0]*i + [1]
val1 = herme.hermeval(self.x, pol1)
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
pol2 = [0]*j + [1]
val2 = herme.hermeval(self.x, pol2)
pol3 = herme.hermemul(pol1, pol2)
val3 = herme.hermeval(self.x, pol3)
assert_(len(pol3) == i + j + 1, msg)
assert_almost_equal(val3, val1*val2, err_msg=msg)
def test_hermediv(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
ci = [0]*i + [1]
cj = [0]*j + [1]
tgt = herme.hermeadd(ci, cj)
quo, rem = herme.hermediv(tgt, ci)
res = herme.hermeadd(herme.hermemul(quo, ci), rem)
assert_equal(trim(res), trim(tgt), err_msg=msg)
class TestEvaluation(object):
# coefficients of 1 + 2*x + 3*x**2
c1d = np.array([4., 2., 3.])
c2d = np.einsum('i,j->ij', c1d, c1d)
c3d = np.einsum('i,j,k->ijk', c1d, c1d, c1d)
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
y = polyval(x, [1., 2., 3.])
def test_hermeval(self):
#check empty input
assert_equal(herme.hermeval([], [1]).size, 0)
#check normal input)
x = np.linspace(-1, 1)
y = [polyval(x, c) for c in Helist]
for i in range(10):
msg = "At i=%d" % i
tgt = y[i]
res = herme.hermeval(x, [0]*i + [1])
assert_almost_equal(res, tgt, err_msg=msg)
#check that shape is preserved
for i in range(3):
dims = [2]*i
x = np.zeros(dims)
assert_equal(herme.hermeval(x, [1]).shape, dims)
assert_equal(herme.hermeval(x, [1, 0]).shape, dims)
assert_equal(herme.hermeval(x, [1, 0, 0]).shape, dims)
def test_hermeval2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, herme.hermeval2d, x1, x2[:2], self.c2d)
#test values
tgt = y1*y2
res = herme.hermeval2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = herme.hermeval2d(z, z, self.c2d)
assert_(res.shape == (2, 3))
def test_hermeval3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, herme.hermeval3d, x1, x2, x3[:2], self.c3d)
#test values
tgt = y1*y2*y3
res = herme.hermeval3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = herme.hermeval3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3))
def test_hermegrid2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j->ij', y1, y2)
res = herme.hermegrid2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = herme.hermegrid2d(z, z, self.c2d)
assert_(res.shape == (2, 3)*2)
def test_hermegrid3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j,k->ijk', y1, y2, y3)
res = herme.hermegrid3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = herme.hermegrid3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3)*3)
class TestIntegral(object):
def test_hermeint(self):
# check exceptions
assert_raises(ValueError, herme.hermeint, [0], .5)
assert_raises(ValueError, herme.hermeint, [0], -1)
assert_raises(ValueError, herme.hermeint, [0], 1, [0, 0])
assert_raises(ValueError, herme.hermeint, [0], lbnd=[0])
assert_raises(ValueError, herme.hermeint, [0], scl=[0])
assert_raises(ValueError, herme.hermeint, [0], axis=.5)
# test integration of zero polynomial
for i in range(2, 5):
k = [0]*(i - 2) + [1]
res = herme.hermeint([0], m=i, k=k)
assert_almost_equal(res, [0, 1])
# check single integration with integration constant
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [1/scl]
hermepol = herme.poly2herme(pol)
hermeint = herme.hermeint(hermepol, m=1, k=[i])
res = herme.herme2poly(hermeint)
assert_almost_equal(trim(res), trim(tgt))
# check single integration with integration constant and lbnd
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
hermepol = herme.poly2herme(pol)
hermeint = herme.hermeint(hermepol, m=1, k=[i], lbnd=-1)
assert_almost_equal(herme.hermeval(-1, hermeint), i)
# check single integration with integration constant and scaling
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [2/scl]
hermepol = herme.poly2herme(pol)
hermeint = herme.hermeint(hermepol, m=1, k=[i], scl=2)
res = herme.herme2poly(hermeint)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with default k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = herme.hermeint(tgt, m=1)
res = herme.hermeint(pol, m=j)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with defined k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = herme.hermeint(tgt, m=1, k=[k])
res = herme.hermeint(pol, m=j, k=list(range(j)))
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with lbnd
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = herme.hermeint(tgt, m=1, k=[k], lbnd=-1)
res = herme.hermeint(pol, m=j, k=list(range(j)), lbnd=-1)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with scaling
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = herme.hermeint(tgt, m=1, k=[k], scl=2)
res = herme.hermeint(pol, m=j, k=list(range(j)), scl=2)
assert_almost_equal(trim(res), trim(tgt))
def test_hermeint_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([herme.hermeint(c) for c in c2d.T]).T
res = herme.hermeint(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([herme.hermeint(c) for c in c2d])
res = herme.hermeint(c2d, axis=1)
assert_almost_equal(res, tgt)
tgt = np.vstack([herme.hermeint(c, k=3) for c in c2d])
res = herme.hermeint(c2d, k=3, axis=1)
assert_almost_equal(res, tgt)
class TestDerivative(object):
def test_hermeder(self):
# check exceptions
assert_raises(ValueError, herme.hermeder, [0], .5)
assert_raises(ValueError, herme.hermeder, [0], -1)
# check that zeroth derivative does nothing
for i in range(5):
tgt = [0]*i + [1]
res = herme.hermeder(tgt, m=0)
assert_equal(trim(res), trim(tgt))
# check that derivation is the inverse of integration
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = herme.hermeder(herme.hermeint(tgt, m=j), m=j)
assert_almost_equal(trim(res), trim(tgt))
# check derivation with scaling
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = herme.hermeder(
herme.hermeint(tgt, m=j, scl=2), m=j, scl=.5)
assert_almost_equal(trim(res), trim(tgt))
def test_hermeder_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([herme.hermeder(c) for c in c2d.T]).T
res = herme.hermeder(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([herme.hermeder(c) for c in c2d])
res = herme.hermeder(c2d, axis=1)
assert_almost_equal(res, tgt)
class TestVander(object):
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
def test_hermevander(self):
# check for 1d x
x = np.arange(3)
v = herme.hermevander(x, 3)
assert_(v.shape == (3, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], herme.hermeval(x, coef))
# check for 2d x
x = np.array([[1, 2], [3, 4], [5, 6]])
v = herme.hermevander(x, 3)
assert_(v.shape == (3, 2, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], herme.hermeval(x, coef))
def test_hermevander2d(self):
# also tests hermeval2d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3))
van = herme.hermevander2d(x1, x2, [1, 2])
tgt = herme.hermeval2d(x1, x2, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = herme.hermevander2d([x1], [x2], [1, 2])
assert_(van.shape == (1, 5, 6))
def test_hermevander3d(self):
# also tests hermeval3d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3, 4))
van = herme.hermevander3d(x1, x2, x3, [1, 2, 3])
tgt = herme.hermeval3d(x1, x2, x3, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = herme.hermevander3d([x1], [x2], [x3], [1, 2, 3])
assert_(van.shape == (1, 5, 24))
class TestFitting(object):
def test_hermefit(self):
def f(x):
return x*(x - 1)*(x - 2)
def f2(x):
return x**4 + x**2 + 1
# Test exceptions
assert_raises(ValueError, herme.hermefit, [1], [1], -1)
assert_raises(TypeError, herme.hermefit, [[1]], [1], 0)
assert_raises(TypeError, herme.hermefit, [], [1], 0)
assert_raises(TypeError, herme.hermefit, [1], [[[1]]], 0)
assert_raises(TypeError, herme.hermefit, [1, 2], [1], 0)
assert_raises(TypeError, herme.hermefit, [1], [1, 2], 0)
assert_raises(TypeError, herme.hermefit, [1], [1], 0, w=[[1]])
assert_raises(TypeError, herme.hermefit, [1], [1], 0, w=[1, 1])
assert_raises(ValueError, herme.hermefit, [1], [1], [-1,])
assert_raises(ValueError, herme.hermefit, [1], [1], [2, -1, 6])
assert_raises(TypeError, herme.hermefit, [1], [1], [])
# Test fit
x = np.linspace(0, 2)
y = f(x)
#
coef3 = herme.hermefit(x, y, 3)
assert_equal(len(coef3), 4)
assert_almost_equal(herme.hermeval(x, coef3), y)
coef3 = herme.hermefit(x, y, [0, 1, 2, 3])
assert_equal(len(coef3), 4)
assert_almost_equal(herme.hermeval(x, coef3), y)
#
coef4 = herme.hermefit(x, y, 4)
assert_equal(len(coef4), 5)
assert_almost_equal(herme.hermeval(x, coef4), y)
coef4 = herme.hermefit(x, y, [0, 1, 2, 3, 4])
assert_equal(len(coef4), 5)
assert_almost_equal(herme.hermeval(x, coef4), y)
# check things still work if deg is not in strict increasing
coef4 = herme.hermefit(x, y, [2, 3, 4, 1, 0])
assert_equal(len(coef4), 5)
assert_almost_equal(herme.hermeval(x, coef4), y)
#
coef2d = herme.hermefit(x, np.array([y, y]).T, 3)
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
coef2d = herme.hermefit(x, np.array([y, y]).T, [0, 1, 2, 3])
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
# test weighting
w = np.zeros_like(x)
yw = y.copy()
w[1::2] = 1
y[0::2] = 0
wcoef3 = herme.hermefit(x, yw, 3, w=w)
assert_almost_equal(wcoef3, coef3)
wcoef3 = herme.hermefit(x, yw, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef3, coef3)
#
wcoef2d = herme.hermefit(x, np.array([yw, yw]).T, 3, w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
wcoef2d = herme.hermefit(x, np.array([yw, yw]).T, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
# test scaling with complex values x points whose square
# is zero when summed.
x = [1, 1j, -1, -1j]
assert_almost_equal(herme.hermefit(x, x, 1), [0, 1])
assert_almost_equal(herme.hermefit(x, x, [0, 1]), [0, 1])
# test fitting only even Legendre polynomials
x = np.linspace(-1, 1)
y = f2(x)
coef1 = herme.hermefit(x, y, 4)
assert_almost_equal(herme.hermeval(x, coef1), y)
coef2 = herme.hermefit(x, y, [0, 2, 4])
assert_almost_equal(herme.hermeval(x, coef2), y)
assert_almost_equal(coef1, coef2)
class TestCompanion(object):
def test_raises(self):
assert_raises(ValueError, herme.hermecompanion, [])
assert_raises(ValueError, herme.hermecompanion, [1])
def test_dimensions(self):
for i in range(1, 5):
coef = [0]*i + [1]
assert_(herme.hermecompanion(coef).shape == (i, i))
def test_linear_root(self):
assert_(herme.hermecompanion([1, 2])[0, 0] == -.5)
class TestGauss(object):
def test_100(self):
x, w = herme.hermegauss(100)
# test orthogonality. Note that the results need to be normalized,
# otherwise the huge values that can arise from fast growing
# functions like Laguerre can be very confusing.
v = herme.hermevander(x, 99)
vv = np.dot(v.T * w, v)
vd = 1/np.sqrt(vv.diagonal())
vv = vd[:, None] * vv * vd
assert_almost_equal(vv, np.eye(100))
# check that the integral of 1 is correct
tgt = np.sqrt(2*np.pi)
assert_almost_equal(w.sum(), tgt)
class TestMisc(object):
def test_hermefromroots(self):
res = herme.hermefromroots([])
assert_almost_equal(trim(res), [1])
for i in range(1, 5):
roots = np.cos(np.linspace(-np.pi, 0, 2*i + 1)[1::2])
pol = herme.hermefromroots(roots)
res = herme.hermeval(roots, pol)
tgt = 0
assert_(len(pol) == i + 1)
assert_almost_equal(herme.herme2poly(pol)[-1], 1)
assert_almost_equal(res, tgt)
def test_hermeroots(self):
assert_almost_equal(herme.hermeroots([1]), [])
assert_almost_equal(herme.hermeroots([1, 1]), [-1])
for i in range(2, 5):
tgt = np.linspace(-1, 1, i)
res = herme.hermeroots(herme.hermefromroots(tgt))
assert_almost_equal(trim(res), trim(tgt))
def test_hermetrim(self):
coef = [2, -1, 1, 0]
# Test exceptions
assert_raises(ValueError, herme.hermetrim, coef, -1)
# Test results
assert_equal(herme.hermetrim(coef), coef[:-1])
assert_equal(herme.hermetrim(coef, 1), coef[:-3])
assert_equal(herme.hermetrim(coef, 2), [0])
def test_hermeline(self):
assert_equal(herme.hermeline(3, 4), [3, 4])
def test_herme2poly(self):
for i in range(10):
assert_almost_equal(herme.herme2poly([0]*i + [1]), Helist[i])
def test_poly2herme(self):
for i in range(10):
assert_almost_equal(herme.poly2herme(Helist[i]), [0]*i + [1])
def test_weight(self):
x = np.linspace(-5, 5, 11)
tgt = np.exp(-.5*x**2)
res = herme.hermeweight(x)
assert_almost_equal(res, tgt)
if __name__ == "__main__":
run_module_suite()

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"""Tests for laguerre module.
"""
from __future__ import division, absolute_import, print_function
import numpy as np
import numpy.polynomial.laguerre as lag
from numpy.polynomial.polynomial import polyval
from numpy.testing import (
assert_almost_equal, assert_raises, assert_equal, assert_,
run_module_suite
)
L0 = np.array([1])/1
L1 = np.array([1, -1])/1
L2 = np.array([2, -4, 1])/2
L3 = np.array([6, -18, 9, -1])/6
L4 = np.array([24, -96, 72, -16, 1])/24
L5 = np.array([120, -600, 600, -200, 25, -1])/120
L6 = np.array([720, -4320, 5400, -2400, 450, -36, 1])/720
Llist = [L0, L1, L2, L3, L4, L5, L6]
def trim(x):
return lag.lagtrim(x, tol=1e-6)
class TestConstants(object):
def test_lagdomain(self):
assert_equal(lag.lagdomain, [0, 1])
def test_lagzero(self):
assert_equal(lag.lagzero, [0])
def test_lagone(self):
assert_equal(lag.lagone, [1])
def test_lagx(self):
assert_equal(lag.lagx, [1, -1])
class TestArithmetic(object):
x = np.linspace(-3, 3, 100)
def test_lagadd(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] += 1
res = lag.lagadd([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_lagsub(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] -= 1
res = lag.lagsub([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_lagmulx(self):
assert_equal(lag.lagmulx([0]), [0])
assert_equal(lag.lagmulx([1]), [1, -1])
for i in range(1, 5):
ser = [0]*i + [1]
tgt = [0]*(i - 1) + [-i, 2*i + 1, -(i + 1)]
assert_almost_equal(lag.lagmulx(ser), tgt)
def test_lagmul(self):
# check values of result
for i in range(5):
pol1 = [0]*i + [1]
val1 = lag.lagval(self.x, pol1)
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
pol2 = [0]*j + [1]
val2 = lag.lagval(self.x, pol2)
pol3 = lag.lagmul(pol1, pol2)
val3 = lag.lagval(self.x, pol3)
assert_(len(pol3) == i + j + 1, msg)
assert_almost_equal(val3, val1*val2, err_msg=msg)
def test_lagdiv(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
ci = [0]*i + [1]
cj = [0]*j + [1]
tgt = lag.lagadd(ci, cj)
quo, rem = lag.lagdiv(tgt, ci)
res = lag.lagadd(lag.lagmul(quo, ci), rem)
assert_almost_equal(trim(res), trim(tgt), err_msg=msg)
class TestEvaluation(object):
# coefficients of 1 + 2*x + 3*x**2
c1d = np.array([9., -14., 6.])
c2d = np.einsum('i,j->ij', c1d, c1d)
c3d = np.einsum('i,j,k->ijk', c1d, c1d, c1d)
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
y = polyval(x, [1., 2., 3.])
def test_lagval(self):
#check empty input
assert_equal(lag.lagval([], [1]).size, 0)
#check normal input)
x = np.linspace(-1, 1)
y = [polyval(x, c) for c in Llist]
for i in range(7):
msg = "At i=%d" % i
tgt = y[i]
res = lag.lagval(x, [0]*i + [1])
assert_almost_equal(res, tgt, err_msg=msg)
#check that shape is preserved
for i in range(3):
dims = [2]*i
x = np.zeros(dims)
assert_equal(lag.lagval(x, [1]).shape, dims)
assert_equal(lag.lagval(x, [1, 0]).shape, dims)
assert_equal(lag.lagval(x, [1, 0, 0]).shape, dims)
def test_lagval2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, lag.lagval2d, x1, x2[:2], self.c2d)
#test values
tgt = y1*y2
res = lag.lagval2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = lag.lagval2d(z, z, self.c2d)
assert_(res.shape == (2, 3))
def test_lagval3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, lag.lagval3d, x1, x2, x3[:2], self.c3d)
#test values
tgt = y1*y2*y3
res = lag.lagval3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = lag.lagval3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3))
def test_laggrid2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j->ij', y1, y2)
res = lag.laggrid2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = lag.laggrid2d(z, z, self.c2d)
assert_(res.shape == (2, 3)*2)
def test_laggrid3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j,k->ijk', y1, y2, y3)
res = lag.laggrid3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = lag.laggrid3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3)*3)
class TestIntegral(object):
def test_lagint(self):
# check exceptions
assert_raises(ValueError, lag.lagint, [0], .5)
assert_raises(ValueError, lag.lagint, [0], -1)
assert_raises(ValueError, lag.lagint, [0], 1, [0, 0])
assert_raises(ValueError, lag.lagint, [0], lbnd=[0])
assert_raises(ValueError, lag.lagint, [0], scl=[0])
assert_raises(ValueError, lag.lagint, [0], axis=.5)
# test integration of zero polynomial
for i in range(2, 5):
k = [0]*(i - 2) + [1]
res = lag.lagint([0], m=i, k=k)
assert_almost_equal(res, [1, -1])
# check single integration with integration constant
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [1/scl]
lagpol = lag.poly2lag(pol)
lagint = lag.lagint(lagpol, m=1, k=[i])
res = lag.lag2poly(lagint)
assert_almost_equal(trim(res), trim(tgt))
# check single integration with integration constant and lbnd
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
lagpol = lag.poly2lag(pol)
lagint = lag.lagint(lagpol, m=1, k=[i], lbnd=-1)
assert_almost_equal(lag.lagval(-1, lagint), i)
# check single integration with integration constant and scaling
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [2/scl]
lagpol = lag.poly2lag(pol)
lagint = lag.lagint(lagpol, m=1, k=[i], scl=2)
res = lag.lag2poly(lagint)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with default k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = lag.lagint(tgt, m=1)
res = lag.lagint(pol, m=j)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with defined k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = lag.lagint(tgt, m=1, k=[k])
res = lag.lagint(pol, m=j, k=list(range(j)))
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with lbnd
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = lag.lagint(tgt, m=1, k=[k], lbnd=-1)
res = lag.lagint(pol, m=j, k=list(range(j)), lbnd=-1)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with scaling
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = lag.lagint(tgt, m=1, k=[k], scl=2)
res = lag.lagint(pol, m=j, k=list(range(j)), scl=2)
assert_almost_equal(trim(res), trim(tgt))
def test_lagint_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([lag.lagint(c) for c in c2d.T]).T
res = lag.lagint(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([lag.lagint(c) for c in c2d])
res = lag.lagint(c2d, axis=1)
assert_almost_equal(res, tgt)
tgt = np.vstack([lag.lagint(c, k=3) for c in c2d])
res = lag.lagint(c2d, k=3, axis=1)
assert_almost_equal(res, tgt)
class TestDerivative(object):
def test_lagder(self):
# check exceptions
assert_raises(ValueError, lag.lagder, [0], .5)
assert_raises(ValueError, lag.lagder, [0], -1)
# check that zeroth derivative does nothing
for i in range(5):
tgt = [0]*i + [1]
res = lag.lagder(tgt, m=0)
assert_equal(trim(res), trim(tgt))
# check that derivation is the inverse of integration
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = lag.lagder(lag.lagint(tgt, m=j), m=j)
assert_almost_equal(trim(res), trim(tgt))
# check derivation with scaling
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = lag.lagder(lag.lagint(tgt, m=j, scl=2), m=j, scl=.5)
assert_almost_equal(trim(res), trim(tgt))
def test_lagder_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([lag.lagder(c) for c in c2d.T]).T
res = lag.lagder(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([lag.lagder(c) for c in c2d])
res = lag.lagder(c2d, axis=1)
assert_almost_equal(res, tgt)
class TestVander(object):
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
def test_lagvander(self):
# check for 1d x
x = np.arange(3)
v = lag.lagvander(x, 3)
assert_(v.shape == (3, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], lag.lagval(x, coef))
# check for 2d x
x = np.array([[1, 2], [3, 4], [5, 6]])
v = lag.lagvander(x, 3)
assert_(v.shape == (3, 2, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], lag.lagval(x, coef))
def test_lagvander2d(self):
# also tests lagval2d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3))
van = lag.lagvander2d(x1, x2, [1, 2])
tgt = lag.lagval2d(x1, x2, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = lag.lagvander2d([x1], [x2], [1, 2])
assert_(van.shape == (1, 5, 6))
def test_lagvander3d(self):
# also tests lagval3d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3, 4))
van = lag.lagvander3d(x1, x2, x3, [1, 2, 3])
tgt = lag.lagval3d(x1, x2, x3, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = lag.lagvander3d([x1], [x2], [x3], [1, 2, 3])
assert_(van.shape == (1, 5, 24))
class TestFitting(object):
def test_lagfit(self):
def f(x):
return x*(x - 1)*(x - 2)
# Test exceptions
assert_raises(ValueError, lag.lagfit, [1], [1], -1)
assert_raises(TypeError, lag.lagfit, [[1]], [1], 0)
assert_raises(TypeError, lag.lagfit, [], [1], 0)
assert_raises(TypeError, lag.lagfit, [1], [[[1]]], 0)
assert_raises(TypeError, lag.lagfit, [1, 2], [1], 0)
assert_raises(TypeError, lag.lagfit, [1], [1, 2], 0)
assert_raises(TypeError, lag.lagfit, [1], [1], 0, w=[[1]])
assert_raises(TypeError, lag.lagfit, [1], [1], 0, w=[1, 1])
assert_raises(ValueError, lag.lagfit, [1], [1], [-1,])
assert_raises(ValueError, lag.lagfit, [1], [1], [2, -1, 6])
assert_raises(TypeError, lag.lagfit, [1], [1], [])
# Test fit
x = np.linspace(0, 2)
y = f(x)
#
coef3 = lag.lagfit(x, y, 3)
assert_equal(len(coef3), 4)
assert_almost_equal(lag.lagval(x, coef3), y)
coef3 = lag.lagfit(x, y, [0, 1, 2, 3])
assert_equal(len(coef3), 4)
assert_almost_equal(lag.lagval(x, coef3), y)
#
coef4 = lag.lagfit(x, y, 4)
assert_equal(len(coef4), 5)
assert_almost_equal(lag.lagval(x, coef4), y)
coef4 = lag.lagfit(x, y, [0, 1, 2, 3, 4])
assert_equal(len(coef4), 5)
assert_almost_equal(lag.lagval(x, coef4), y)
#
coef2d = lag.lagfit(x, np.array([y, y]).T, 3)
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
coef2d = lag.lagfit(x, np.array([y, y]).T, [0, 1, 2, 3])
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
# test weighting
w = np.zeros_like(x)
yw = y.copy()
w[1::2] = 1
y[0::2] = 0
wcoef3 = lag.lagfit(x, yw, 3, w=w)
assert_almost_equal(wcoef3, coef3)
wcoef3 = lag.lagfit(x, yw, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef3, coef3)
#
wcoef2d = lag.lagfit(x, np.array([yw, yw]).T, 3, w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
wcoef2d = lag.lagfit(x, np.array([yw, yw]).T, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
# test scaling with complex values x points whose square
# is zero when summed.
x = [1, 1j, -1, -1j]
assert_almost_equal(lag.lagfit(x, x, 1), [1, -1])
assert_almost_equal(lag.lagfit(x, x, [0, 1]), [1, -1])
class TestCompanion(object):
def test_raises(self):
assert_raises(ValueError, lag.lagcompanion, [])
assert_raises(ValueError, lag.lagcompanion, [1])
def test_dimensions(self):
for i in range(1, 5):
coef = [0]*i + [1]
assert_(lag.lagcompanion(coef).shape == (i, i))
def test_linear_root(self):
assert_(lag.lagcompanion([1, 2])[0, 0] == 1.5)
class TestGauss(object):
def test_100(self):
x, w = lag.laggauss(100)
# test orthogonality. Note that the results need to be normalized,
# otherwise the huge values that can arise from fast growing
# functions like Laguerre can be very confusing.
v = lag.lagvander(x, 99)
vv = np.dot(v.T * w, v)
vd = 1/np.sqrt(vv.diagonal())
vv = vd[:, None] * vv * vd
assert_almost_equal(vv, np.eye(100))
# check that the integral of 1 is correct
tgt = 1.0
assert_almost_equal(w.sum(), tgt)
class TestMisc(object):
def test_lagfromroots(self):
res = lag.lagfromroots([])
assert_almost_equal(trim(res), [1])
for i in range(1, 5):
roots = np.cos(np.linspace(-np.pi, 0, 2*i + 1)[1::2])
pol = lag.lagfromroots(roots)
res = lag.lagval(roots, pol)
tgt = 0
assert_(len(pol) == i + 1)
assert_almost_equal(lag.lag2poly(pol)[-1], 1)
assert_almost_equal(res, tgt)
def test_lagroots(self):
assert_almost_equal(lag.lagroots([1]), [])
assert_almost_equal(lag.lagroots([0, 1]), [1])
for i in range(2, 5):
tgt = np.linspace(0, 3, i)
res = lag.lagroots(lag.lagfromroots(tgt))
assert_almost_equal(trim(res), trim(tgt))
def test_lagtrim(self):
coef = [2, -1, 1, 0]
# Test exceptions
assert_raises(ValueError, lag.lagtrim, coef, -1)
# Test results
assert_equal(lag.lagtrim(coef), coef[:-1])
assert_equal(lag.lagtrim(coef, 1), coef[:-3])
assert_equal(lag.lagtrim(coef, 2), [0])
def test_lagline(self):
assert_equal(lag.lagline(3, 4), [7, -4])
def test_lag2poly(self):
for i in range(7):
assert_almost_equal(lag.lag2poly([0]*i + [1]), Llist[i])
def test_poly2lag(self):
for i in range(7):
assert_almost_equal(lag.poly2lag(Llist[i]), [0]*i + [1])
def test_weight(self):
x = np.linspace(0, 10, 11)
tgt = np.exp(-x)
res = lag.lagweight(x)
assert_almost_equal(res, tgt)
if __name__ == "__main__":
run_module_suite()

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"""Tests for legendre module.
"""
from __future__ import division, absolute_import, print_function
import numpy as np
import numpy.polynomial.legendre as leg
from numpy.polynomial.polynomial import polyval
from numpy.testing import (
assert_almost_equal, assert_raises, assert_equal, assert_,
run_module_suite
)
L0 = np.array([1])
L1 = np.array([0, 1])
L2 = np.array([-1, 0, 3])/2
L3 = np.array([0, -3, 0, 5])/2
L4 = np.array([3, 0, -30, 0, 35])/8
L5 = np.array([0, 15, 0, -70, 0, 63])/8
L6 = np.array([-5, 0, 105, 0, -315, 0, 231])/16
L7 = np.array([0, -35, 0, 315, 0, -693, 0, 429])/16
L8 = np.array([35, 0, -1260, 0, 6930, 0, -12012, 0, 6435])/128
L9 = np.array([0, 315, 0, -4620, 0, 18018, 0, -25740, 0, 12155])/128
Llist = [L0, L1, L2, L3, L4, L5, L6, L7, L8, L9]
def trim(x):
return leg.legtrim(x, tol=1e-6)
class TestConstants(object):
def test_legdomain(self):
assert_equal(leg.legdomain, [-1, 1])
def test_legzero(self):
assert_equal(leg.legzero, [0])
def test_legone(self):
assert_equal(leg.legone, [1])
def test_legx(self):
assert_equal(leg.legx, [0, 1])
class TestArithmetic(object):
x = np.linspace(-1, 1, 100)
def test_legadd(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] += 1
res = leg.legadd([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_legsub(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] -= 1
res = leg.legsub([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_legmulx(self):
assert_equal(leg.legmulx([0]), [0])
assert_equal(leg.legmulx([1]), [0, 1])
for i in range(1, 5):
tmp = 2*i + 1
ser = [0]*i + [1]
tgt = [0]*(i - 1) + [i/tmp, 0, (i + 1)/tmp]
assert_equal(leg.legmulx(ser), tgt)
def test_legmul(self):
# check values of result
for i in range(5):
pol1 = [0]*i + [1]
val1 = leg.legval(self.x, pol1)
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
pol2 = [0]*j + [1]
val2 = leg.legval(self.x, pol2)
pol3 = leg.legmul(pol1, pol2)
val3 = leg.legval(self.x, pol3)
assert_(len(pol3) == i + j + 1, msg)
assert_almost_equal(val3, val1*val2, err_msg=msg)
def test_legdiv(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
ci = [0]*i + [1]
cj = [0]*j + [1]
tgt = leg.legadd(ci, cj)
quo, rem = leg.legdiv(tgt, ci)
res = leg.legadd(leg.legmul(quo, ci), rem)
assert_equal(trim(res), trim(tgt), err_msg=msg)
class TestEvaluation(object):
# coefficients of 1 + 2*x + 3*x**2
c1d = np.array([2., 2., 2.])
c2d = np.einsum('i,j->ij', c1d, c1d)
c3d = np.einsum('i,j,k->ijk', c1d, c1d, c1d)
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
y = polyval(x, [1., 2., 3.])
def test_legval(self):
#check empty input
assert_equal(leg.legval([], [1]).size, 0)
#check normal input)
x = np.linspace(-1, 1)
y = [polyval(x, c) for c in Llist]
for i in range(10):
msg = "At i=%d" % i
tgt = y[i]
res = leg.legval(x, [0]*i + [1])
assert_almost_equal(res, tgt, err_msg=msg)
#check that shape is preserved
for i in range(3):
dims = [2]*i
x = np.zeros(dims)
assert_equal(leg.legval(x, [1]).shape, dims)
assert_equal(leg.legval(x, [1, 0]).shape, dims)
assert_equal(leg.legval(x, [1, 0, 0]).shape, dims)
def test_legval2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, leg.legval2d, x1, x2[:2], self.c2d)
#test values
tgt = y1*y2
res = leg.legval2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = leg.legval2d(z, z, self.c2d)
assert_(res.shape == (2, 3))
def test_legval3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, leg.legval3d, x1, x2, x3[:2], self.c3d)
#test values
tgt = y1*y2*y3
res = leg.legval3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = leg.legval3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3))
def test_leggrid2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j->ij', y1, y2)
res = leg.leggrid2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = leg.leggrid2d(z, z, self.c2d)
assert_(res.shape == (2, 3)*2)
def test_leggrid3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j,k->ijk', y1, y2, y3)
res = leg.leggrid3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = leg.leggrid3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3)*3)
class TestIntegral(object):
def test_legint(self):
# check exceptions
assert_raises(ValueError, leg.legint, [0], .5)
assert_raises(ValueError, leg.legint, [0], -1)
assert_raises(ValueError, leg.legint, [0], 1, [0, 0])
assert_raises(ValueError, leg.legint, [0], lbnd=[0])
assert_raises(ValueError, leg.legint, [0], scl=[0])
assert_raises(ValueError, leg.legint, [0], axis=.5)
# test integration of zero polynomial
for i in range(2, 5):
k = [0]*(i - 2) + [1]
res = leg.legint([0], m=i, k=k)
assert_almost_equal(res, [0, 1])
# check single integration with integration constant
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [1/scl]
legpol = leg.poly2leg(pol)
legint = leg.legint(legpol, m=1, k=[i])
res = leg.leg2poly(legint)
assert_almost_equal(trim(res), trim(tgt))
# check single integration with integration constant and lbnd
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
legpol = leg.poly2leg(pol)
legint = leg.legint(legpol, m=1, k=[i], lbnd=-1)
assert_almost_equal(leg.legval(-1, legint), i)
# check single integration with integration constant and scaling
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [2/scl]
legpol = leg.poly2leg(pol)
legint = leg.legint(legpol, m=1, k=[i], scl=2)
res = leg.leg2poly(legint)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with default k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = leg.legint(tgt, m=1)
res = leg.legint(pol, m=j)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with defined k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = leg.legint(tgt, m=1, k=[k])
res = leg.legint(pol, m=j, k=list(range(j)))
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with lbnd
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = leg.legint(tgt, m=1, k=[k], lbnd=-1)
res = leg.legint(pol, m=j, k=list(range(j)), lbnd=-1)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with scaling
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = leg.legint(tgt, m=1, k=[k], scl=2)
res = leg.legint(pol, m=j, k=list(range(j)), scl=2)
assert_almost_equal(trim(res), trim(tgt))
def test_legint_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([leg.legint(c) for c in c2d.T]).T
res = leg.legint(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([leg.legint(c) for c in c2d])
res = leg.legint(c2d, axis=1)
assert_almost_equal(res, tgt)
tgt = np.vstack([leg.legint(c, k=3) for c in c2d])
res = leg.legint(c2d, k=3, axis=1)
assert_almost_equal(res, tgt)
class TestDerivative(object):
def test_legder(self):
# check exceptions
assert_raises(ValueError, leg.legder, [0], .5)
assert_raises(ValueError, leg.legder, [0], -1)
# check that zeroth derivative does nothing
for i in range(5):
tgt = [0]*i + [1]
res = leg.legder(tgt, m=0)
assert_equal(trim(res), trim(tgt))
# check that derivation is the inverse of integration
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = leg.legder(leg.legint(tgt, m=j), m=j)
assert_almost_equal(trim(res), trim(tgt))
# check derivation with scaling
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = leg.legder(leg.legint(tgt, m=j, scl=2), m=j, scl=.5)
assert_almost_equal(trim(res), trim(tgt))
def test_legder_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([leg.legder(c) for c in c2d.T]).T
res = leg.legder(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([leg.legder(c) for c in c2d])
res = leg.legder(c2d, axis=1)
assert_almost_equal(res, tgt)
class TestVander(object):
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
def test_legvander(self):
# check for 1d x
x = np.arange(3)
v = leg.legvander(x, 3)
assert_(v.shape == (3, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], leg.legval(x, coef))
# check for 2d x
x = np.array([[1, 2], [3, 4], [5, 6]])
v = leg.legvander(x, 3)
assert_(v.shape == (3, 2, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], leg.legval(x, coef))
def test_legvander2d(self):
# also tests polyval2d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3))
van = leg.legvander2d(x1, x2, [1, 2])
tgt = leg.legval2d(x1, x2, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = leg.legvander2d([x1], [x2], [1, 2])
assert_(van.shape == (1, 5, 6))
def test_legvander3d(self):
# also tests polyval3d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3, 4))
van = leg.legvander3d(x1, x2, x3, [1, 2, 3])
tgt = leg.legval3d(x1, x2, x3, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = leg.legvander3d([x1], [x2], [x3], [1, 2, 3])
assert_(van.shape == (1, 5, 24))
class TestFitting(object):
def test_legfit(self):
def f(x):
return x*(x - 1)*(x - 2)
def f2(x):
return x**4 + x**2 + 1
# Test exceptions
assert_raises(ValueError, leg.legfit, [1], [1], -1)
assert_raises(TypeError, leg.legfit, [[1]], [1], 0)
assert_raises(TypeError, leg.legfit, [], [1], 0)
assert_raises(TypeError, leg.legfit, [1], [[[1]]], 0)
assert_raises(TypeError, leg.legfit, [1, 2], [1], 0)
assert_raises(TypeError, leg.legfit, [1], [1, 2], 0)
assert_raises(TypeError, leg.legfit, [1], [1], 0, w=[[1]])
assert_raises(TypeError, leg.legfit, [1], [1], 0, w=[1, 1])
assert_raises(ValueError, leg.legfit, [1], [1], [-1,])
assert_raises(ValueError, leg.legfit, [1], [1], [2, -1, 6])
assert_raises(TypeError, leg.legfit, [1], [1], [])
# Test fit
x = np.linspace(0, 2)
y = f(x)
#
coef3 = leg.legfit(x, y, 3)
assert_equal(len(coef3), 4)
assert_almost_equal(leg.legval(x, coef3), y)
coef3 = leg.legfit(x, y, [0, 1, 2, 3])
assert_equal(len(coef3), 4)
assert_almost_equal(leg.legval(x, coef3), y)
#
coef4 = leg.legfit(x, y, 4)
assert_equal(len(coef4), 5)
assert_almost_equal(leg.legval(x, coef4), y)
coef4 = leg.legfit(x, y, [0, 1, 2, 3, 4])
assert_equal(len(coef4), 5)
assert_almost_equal(leg.legval(x, coef4), y)
# check things still work if deg is not in strict increasing
coef4 = leg.legfit(x, y, [2, 3, 4, 1, 0])
assert_equal(len(coef4), 5)
assert_almost_equal(leg.legval(x, coef4), y)
#
coef2d = leg.legfit(x, np.array([y, y]).T, 3)
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
coef2d = leg.legfit(x, np.array([y, y]).T, [0, 1, 2, 3])
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
# test weighting
w = np.zeros_like(x)
yw = y.copy()
w[1::2] = 1
y[0::2] = 0
wcoef3 = leg.legfit(x, yw, 3, w=w)
assert_almost_equal(wcoef3, coef3)
wcoef3 = leg.legfit(x, yw, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef3, coef3)
#
wcoef2d = leg.legfit(x, np.array([yw, yw]).T, 3, w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
wcoef2d = leg.legfit(x, np.array([yw, yw]).T, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
# test scaling with complex values x points whose square
# is zero when summed.
x = [1, 1j, -1, -1j]
assert_almost_equal(leg.legfit(x, x, 1), [0, 1])
assert_almost_equal(leg.legfit(x, x, [0, 1]), [0, 1])
# test fitting only even Legendre polynomials
x = np.linspace(-1, 1)
y = f2(x)
coef1 = leg.legfit(x, y, 4)
assert_almost_equal(leg.legval(x, coef1), y)
coef2 = leg.legfit(x, y, [0, 2, 4])
assert_almost_equal(leg.legval(x, coef2), y)
assert_almost_equal(coef1, coef2)
class TestCompanion(object):
def test_raises(self):
assert_raises(ValueError, leg.legcompanion, [])
assert_raises(ValueError, leg.legcompanion, [1])
def test_dimensions(self):
for i in range(1, 5):
coef = [0]*i + [1]
assert_(leg.legcompanion(coef).shape == (i, i))
def test_linear_root(self):
assert_(leg.legcompanion([1, 2])[0, 0] == -.5)
class TestGauss(object):
def test_100(self):
x, w = leg.leggauss(100)
# test orthogonality. Note that the results need to be normalized,
# otherwise the huge values that can arise from fast growing
# functions like Laguerre can be very confusing.
v = leg.legvander(x, 99)
vv = np.dot(v.T * w, v)
vd = 1/np.sqrt(vv.diagonal())
vv = vd[:, None] * vv * vd
assert_almost_equal(vv, np.eye(100))
# check that the integral of 1 is correct
tgt = 2.0
assert_almost_equal(w.sum(), tgt)
class TestMisc(object):
def test_legfromroots(self):
res = leg.legfromroots([])
assert_almost_equal(trim(res), [1])
for i in range(1, 5):
roots = np.cos(np.linspace(-np.pi, 0, 2*i + 1)[1::2])
pol = leg.legfromroots(roots)
res = leg.legval(roots, pol)
tgt = 0
assert_(len(pol) == i + 1)
assert_almost_equal(leg.leg2poly(pol)[-1], 1)
assert_almost_equal(res, tgt)
def test_legroots(self):
assert_almost_equal(leg.legroots([1]), [])
assert_almost_equal(leg.legroots([1, 2]), [-.5])
for i in range(2, 5):
tgt = np.linspace(-1, 1, i)
res = leg.legroots(leg.legfromroots(tgt))
assert_almost_equal(trim(res), trim(tgt))
def test_legtrim(self):
coef = [2, -1, 1, 0]
# Test exceptions
assert_raises(ValueError, leg.legtrim, coef, -1)
# Test results
assert_equal(leg.legtrim(coef), coef[:-1])
assert_equal(leg.legtrim(coef, 1), coef[:-3])
assert_equal(leg.legtrim(coef, 2), [0])
def test_legline(self):
assert_equal(leg.legline(3, 4), [3, 4])
def test_leg2poly(self):
for i in range(10):
assert_almost_equal(leg.leg2poly([0]*i + [1]), Llist[i])
def test_poly2leg(self):
for i in range(10):
assert_almost_equal(leg.poly2leg(Llist[i]), [0]*i + [1])
def test_weight(self):
x = np.linspace(-1, 1, 11)
tgt = 1.
res = leg.legweight(x)
assert_almost_equal(res, tgt)
if __name__ == "__main__":
run_module_suite()

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"""Tests for polynomial module.
"""
from __future__ import division, absolute_import, print_function
import numpy as np
import numpy.polynomial.polynomial as poly
from numpy.testing import (
assert_almost_equal, assert_raises, assert_equal, assert_,
run_module_suite
)
def trim(x):
return poly.polytrim(x, tol=1e-6)
T0 = [1]
T1 = [0, 1]
T2 = [-1, 0, 2]
T3 = [0, -3, 0, 4]
T4 = [1, 0, -8, 0, 8]
T5 = [0, 5, 0, -20, 0, 16]
T6 = [-1, 0, 18, 0, -48, 0, 32]
T7 = [0, -7, 0, 56, 0, -112, 0, 64]
T8 = [1, 0, -32, 0, 160, 0, -256, 0, 128]
T9 = [0, 9, 0, -120, 0, 432, 0, -576, 0, 256]
Tlist = [T0, T1, T2, T3, T4, T5, T6, T7, T8, T9]
class TestConstants(object):
def test_polydomain(self):
assert_equal(poly.polydomain, [-1, 1])
def test_polyzero(self):
assert_equal(poly.polyzero, [0])
def test_polyone(self):
assert_equal(poly.polyone, [1])
def test_polyx(self):
assert_equal(poly.polyx, [0, 1])
class TestArithmetic(object):
def test_polyadd(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] += 1
res = poly.polyadd([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_polysub(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(max(i, j) + 1)
tgt[i] += 1
tgt[j] -= 1
res = poly.polysub([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_polymulx(self):
assert_equal(poly.polymulx([0]), [0])
assert_equal(poly.polymulx([1]), [0, 1])
for i in range(1, 5):
ser = [0]*i + [1]
tgt = [0]*(i + 1) + [1]
assert_equal(poly.polymulx(ser), tgt)
def test_polymul(self):
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
tgt = np.zeros(i + j + 1)
tgt[i + j] += 1
res = poly.polymul([0]*i + [1], [0]*j + [1])
assert_equal(trim(res), trim(tgt), err_msg=msg)
def test_polydiv(self):
# check zero division
assert_raises(ZeroDivisionError, poly.polydiv, [1], [0])
# check scalar division
quo, rem = poly.polydiv([2], [2])
assert_equal((quo, rem), (1, 0))
quo, rem = poly.polydiv([2, 2], [2])
assert_equal((quo, rem), ((1, 1), 0))
# check rest.
for i in range(5):
for j in range(5):
msg = "At i=%d, j=%d" % (i, j)
ci = [0]*i + [1, 2]
cj = [0]*j + [1, 2]
tgt = poly.polyadd(ci, cj)
quo, rem = poly.polydiv(tgt, ci)
res = poly.polyadd(poly.polymul(quo, ci), rem)
assert_equal(res, tgt, err_msg=msg)
class TestEvaluation(object):
# coefficients of 1 + 2*x + 3*x**2
c1d = np.array([1., 2., 3.])
c2d = np.einsum('i,j->ij', c1d, c1d)
c3d = np.einsum('i,j,k->ijk', c1d, c1d, c1d)
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
y = poly.polyval(x, [1., 2., 3.])
def test_polyval(self):
#check empty input
assert_equal(poly.polyval([], [1]).size, 0)
#check normal input)
x = np.linspace(-1, 1)
y = [x**i for i in range(5)]
for i in range(5):
tgt = y[i]
res = poly.polyval(x, [0]*i + [1])
assert_almost_equal(res, tgt)
tgt = x*(x**2 - 1)
res = poly.polyval(x, [0, -1, 0, 1])
assert_almost_equal(res, tgt)
#check that shape is preserved
for i in range(3):
dims = [2]*i
x = np.zeros(dims)
assert_equal(poly.polyval(x, [1]).shape, dims)
assert_equal(poly.polyval(x, [1, 0]).shape, dims)
assert_equal(poly.polyval(x, [1, 0, 0]).shape, dims)
def test_polyvalfromroots(self):
# check exception for broadcasting x values over root array with
# too few dimensions
assert_raises(ValueError, poly.polyvalfromroots,
[1], [1], tensor=False)
# check empty input
assert_equal(poly.polyvalfromroots([], [1]).size, 0)
assert_(poly.polyvalfromroots([], [1]).shape == (0,))
# check empty input + multidimensional roots
assert_equal(poly.polyvalfromroots([], [[1] * 5]).size, 0)
assert_(poly.polyvalfromroots([], [[1] * 5]).shape == (5, 0))
# check scalar input
assert_equal(poly.polyvalfromroots(1, 1), 0)
assert_(poly.polyvalfromroots(1, np.ones((3, 3))).shape == (3,))
# check normal input)
x = np.linspace(-1, 1)
y = [x**i for i in range(5)]
for i in range(1, 5):
tgt = y[i]
res = poly.polyvalfromroots(x, [0]*i)
assert_almost_equal(res, tgt)
tgt = x*(x - 1)*(x + 1)
res = poly.polyvalfromroots(x, [-1, 0, 1])
assert_almost_equal(res, tgt)
# check that shape is preserved
for i in range(3):
dims = [2]*i
x = np.zeros(dims)
assert_equal(poly.polyvalfromroots(x, [1]).shape, dims)
assert_equal(poly.polyvalfromroots(x, [1, 0]).shape, dims)
assert_equal(poly.polyvalfromroots(x, [1, 0, 0]).shape, dims)
# check compatibility with factorization
ptest = [15, 2, -16, -2, 1]
r = poly.polyroots(ptest)
x = np.linspace(-1, 1)
assert_almost_equal(poly.polyval(x, ptest),
poly.polyvalfromroots(x, r))
# check multidimensional arrays of roots and values
# check tensor=False
rshape = (3, 5)
x = np.arange(-3, 2)
r = np.random.randint(-5, 5, size=rshape)
res = poly.polyvalfromroots(x, r, tensor=False)
tgt = np.empty(r.shape[1:])
for ii in range(tgt.size):
tgt[ii] = poly.polyvalfromroots(x[ii], r[:, ii])
assert_equal(res, tgt)
# check tensor=True
x = np.vstack([x, 2*x])
res = poly.polyvalfromroots(x, r, tensor=True)
tgt = np.empty(r.shape[1:] + x.shape)
for ii in range(r.shape[1]):
for jj in range(x.shape[0]):
tgt[ii, jj, :] = poly.polyvalfromroots(x[jj], r[:, ii])
assert_equal(res, tgt)
def test_polyval2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, poly.polyval2d, x1, x2[:2], self.c2d)
#test values
tgt = y1*y2
res = poly.polyval2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = poly.polyval2d(z, z, self.c2d)
assert_(res.shape == (2, 3))
def test_polyval3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test exceptions
assert_raises(ValueError, poly.polyval3d, x1, x2, x3[:2], self.c3d)
#test values
tgt = y1*y2*y3
res = poly.polyval3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = poly.polyval3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3))
def test_polygrid2d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j->ij', y1, y2)
res = poly.polygrid2d(x1, x2, self.c2d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = poly.polygrid2d(z, z, self.c2d)
assert_(res.shape == (2, 3)*2)
def test_polygrid3d(self):
x1, x2, x3 = self.x
y1, y2, y3 = self.y
#test values
tgt = np.einsum('i,j,k->ijk', y1, y2, y3)
res = poly.polygrid3d(x1, x2, x3, self.c3d)
assert_almost_equal(res, tgt)
#test shape
z = np.ones((2, 3))
res = poly.polygrid3d(z, z, z, self.c3d)
assert_(res.shape == (2, 3)*3)
class TestIntegral(object):
def test_polyint(self):
# check exceptions
assert_raises(ValueError, poly.polyint, [0], .5)
assert_raises(ValueError, poly.polyint, [0], -1)
assert_raises(ValueError, poly.polyint, [0], 1, [0, 0])
assert_raises(ValueError, poly.polyint, [0], lbnd=[0])
assert_raises(ValueError, poly.polyint, [0], scl=[0])
assert_raises(ValueError, poly.polyint, [0], axis=.5)
# test integration of zero polynomial
for i in range(2, 5):
k = [0]*(i - 2) + [1]
res = poly.polyint([0], m=i, k=k)
assert_almost_equal(res, [0, 1])
# check single integration with integration constant
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [1/scl]
res = poly.polyint(pol, m=1, k=[i])
assert_almost_equal(trim(res), trim(tgt))
# check single integration with integration constant and lbnd
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
res = poly.polyint(pol, m=1, k=[i], lbnd=-1)
assert_almost_equal(poly.polyval(-1, res), i)
# check single integration with integration constant and scaling
for i in range(5):
scl = i + 1
pol = [0]*i + [1]
tgt = [i] + [0]*i + [2/scl]
res = poly.polyint(pol, m=1, k=[i], scl=2)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with default k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = poly.polyint(tgt, m=1)
res = poly.polyint(pol, m=j)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with defined k
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = poly.polyint(tgt, m=1, k=[k])
res = poly.polyint(pol, m=j, k=list(range(j)))
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with lbnd
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = poly.polyint(tgt, m=1, k=[k], lbnd=-1)
res = poly.polyint(pol, m=j, k=list(range(j)), lbnd=-1)
assert_almost_equal(trim(res), trim(tgt))
# check multiple integrations with scaling
for i in range(5):
for j in range(2, 5):
pol = [0]*i + [1]
tgt = pol[:]
for k in range(j):
tgt = poly.polyint(tgt, m=1, k=[k], scl=2)
res = poly.polyint(pol, m=j, k=list(range(j)), scl=2)
assert_almost_equal(trim(res), trim(tgt))
def test_polyint_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([poly.polyint(c) for c in c2d.T]).T
res = poly.polyint(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([poly.polyint(c) for c in c2d])
res = poly.polyint(c2d, axis=1)
assert_almost_equal(res, tgt)
tgt = np.vstack([poly.polyint(c, k=3) for c in c2d])
res = poly.polyint(c2d, k=3, axis=1)
assert_almost_equal(res, tgt)
class TestDerivative(object):
def test_polyder(self):
# check exceptions
assert_raises(ValueError, poly.polyder, [0], .5)
assert_raises(ValueError, poly.polyder, [0], -1)
# check that zeroth derivative does nothing
for i in range(5):
tgt = [0]*i + [1]
res = poly.polyder(tgt, m=0)
assert_equal(trim(res), trim(tgt))
# check that derivation is the inverse of integration
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = poly.polyder(poly.polyint(tgt, m=j), m=j)
assert_almost_equal(trim(res), trim(tgt))
# check derivation with scaling
for i in range(5):
for j in range(2, 5):
tgt = [0]*i + [1]
res = poly.polyder(poly.polyint(tgt, m=j, scl=2), m=j, scl=.5)
assert_almost_equal(trim(res), trim(tgt))
def test_polyder_axis(self):
# check that axis keyword works
c2d = np.random.random((3, 4))
tgt = np.vstack([poly.polyder(c) for c in c2d.T]).T
res = poly.polyder(c2d, axis=0)
assert_almost_equal(res, tgt)
tgt = np.vstack([poly.polyder(c) for c in c2d])
res = poly.polyder(c2d, axis=1)
assert_almost_equal(res, tgt)
class TestVander(object):
# some random values in [-1, 1)
x = np.random.random((3, 5))*2 - 1
def test_polyvander(self):
# check for 1d x
x = np.arange(3)
v = poly.polyvander(x, 3)
assert_(v.shape == (3, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], poly.polyval(x, coef))
# check for 2d x
x = np.array([[1, 2], [3, 4], [5, 6]])
v = poly.polyvander(x, 3)
assert_(v.shape == (3, 2, 4))
for i in range(4):
coef = [0]*i + [1]
assert_almost_equal(v[..., i], poly.polyval(x, coef))
def test_polyvander2d(self):
# also tests polyval2d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3))
van = poly.polyvander2d(x1, x2, [1, 2])
tgt = poly.polyval2d(x1, x2, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = poly.polyvander2d([x1], [x2], [1, 2])
assert_(van.shape == (1, 5, 6))
def test_polyvander3d(self):
# also tests polyval3d for non-square coefficient array
x1, x2, x3 = self.x
c = np.random.random((2, 3, 4))
van = poly.polyvander3d(x1, x2, x3, [1, 2, 3])
tgt = poly.polyval3d(x1, x2, x3, c)
res = np.dot(van, c.flat)
assert_almost_equal(res, tgt)
# check shape
van = poly.polyvander3d([x1], [x2], [x3], [1, 2, 3])
assert_(van.shape == (1, 5, 24))
class TestCompanion(object):
def test_raises(self):
assert_raises(ValueError, poly.polycompanion, [])
assert_raises(ValueError, poly.polycompanion, [1])
def test_dimensions(self):
for i in range(1, 5):
coef = [0]*i + [1]
assert_(poly.polycompanion(coef).shape == (i, i))
def test_linear_root(self):
assert_(poly.polycompanion([1, 2])[0, 0] == -.5)
class TestMisc(object):
def test_polyfromroots(self):
res = poly.polyfromroots([])
assert_almost_equal(trim(res), [1])
for i in range(1, 5):
roots = np.cos(np.linspace(-np.pi, 0, 2*i + 1)[1::2])
tgt = Tlist[i]
res = poly.polyfromroots(roots)*2**(i-1)
assert_almost_equal(trim(res), trim(tgt))
def test_polyroots(self):
assert_almost_equal(poly.polyroots([1]), [])
assert_almost_equal(poly.polyroots([1, 2]), [-.5])
for i in range(2, 5):
tgt = np.linspace(-1, 1, i)
res = poly.polyroots(poly.polyfromroots(tgt))
assert_almost_equal(trim(res), trim(tgt))
def test_polyfit(self):
def f(x):
return x*(x - 1)*(x - 2)
def f2(x):
return x**4 + x**2 + 1
# Test exceptions
assert_raises(ValueError, poly.polyfit, [1], [1], -1)
assert_raises(TypeError, poly.polyfit, [[1]], [1], 0)
assert_raises(TypeError, poly.polyfit, [], [1], 0)
assert_raises(TypeError, poly.polyfit, [1], [[[1]]], 0)
assert_raises(TypeError, poly.polyfit, [1, 2], [1], 0)
assert_raises(TypeError, poly.polyfit, [1], [1, 2], 0)
assert_raises(TypeError, poly.polyfit, [1], [1], 0, w=[[1]])
assert_raises(TypeError, poly.polyfit, [1], [1], 0, w=[1, 1])
assert_raises(ValueError, poly.polyfit, [1], [1], [-1,])
assert_raises(ValueError, poly.polyfit, [1], [1], [2, -1, 6])
assert_raises(TypeError, poly.polyfit, [1], [1], [])
# Test fit
x = np.linspace(0, 2)
y = f(x)
#
coef3 = poly.polyfit(x, y, 3)
assert_equal(len(coef3), 4)
assert_almost_equal(poly.polyval(x, coef3), y)
coef3 = poly.polyfit(x, y, [0, 1, 2, 3])
assert_equal(len(coef3), 4)
assert_almost_equal(poly.polyval(x, coef3), y)
#
coef4 = poly.polyfit(x, y, 4)
assert_equal(len(coef4), 5)
assert_almost_equal(poly.polyval(x, coef4), y)
coef4 = poly.polyfit(x, y, [0, 1, 2, 3, 4])
assert_equal(len(coef4), 5)
assert_almost_equal(poly.polyval(x, coef4), y)
#
coef2d = poly.polyfit(x, np.array([y, y]).T, 3)
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
coef2d = poly.polyfit(x, np.array([y, y]).T, [0, 1, 2, 3])
assert_almost_equal(coef2d, np.array([coef3, coef3]).T)
# test weighting
w = np.zeros_like(x)
yw = y.copy()
w[1::2] = 1
yw[0::2] = 0
wcoef3 = poly.polyfit(x, yw, 3, w=w)
assert_almost_equal(wcoef3, coef3)
wcoef3 = poly.polyfit(x, yw, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef3, coef3)
#
wcoef2d = poly.polyfit(x, np.array([yw, yw]).T, 3, w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
wcoef2d = poly.polyfit(x, np.array([yw, yw]).T, [0, 1, 2, 3], w=w)
assert_almost_equal(wcoef2d, np.array([coef3, coef3]).T)
# test scaling with complex values x points whose square
# is zero when summed.
x = [1, 1j, -1, -1j]
assert_almost_equal(poly.polyfit(x, x, 1), [0, 1])
assert_almost_equal(poly.polyfit(x, x, [0, 1]), [0, 1])
# test fitting only even Polyendre polynomials
x = np.linspace(-1, 1)
y = f2(x)
coef1 = poly.polyfit(x, y, 4)
assert_almost_equal(poly.polyval(x, coef1), y)
coef2 = poly.polyfit(x, y, [0, 2, 4])
assert_almost_equal(poly.polyval(x, coef2), y)
assert_almost_equal(coef1, coef2)
def test_polytrim(self):
coef = [2, -1, 1, 0]
# Test exceptions
assert_raises(ValueError, poly.polytrim, coef, -1)
# Test results
assert_equal(poly.polytrim(coef), coef[:-1])
assert_equal(poly.polytrim(coef, 1), coef[:-3])
assert_equal(poly.polytrim(coef, 2), [0])
def test_polyline(self):
assert_equal(poly.polyline(3, 4), [3, 4])
if __name__ == "__main__":
run_module_suite()

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"""Tests for polyutils module.
"""
from __future__ import division, absolute_import, print_function
import numpy as np
import numpy.polynomial.polyutils as pu
from numpy.testing import (
assert_almost_equal, assert_raises, assert_equal, assert_,
run_module_suite
)
class TestMisc(object):
def test_trimseq(self):
for i in range(5):
tgt = [1]
res = pu.trimseq([1] + [0]*5)
assert_equal(res, tgt)
def test_as_series(self):
# check exceptions
assert_raises(ValueError, pu.as_series, [[]])
assert_raises(ValueError, pu.as_series, [[[1, 2]]])
assert_raises(ValueError, pu.as_series, [[1], ['a']])
# check common types
types = ['i', 'd', 'O']
for i in range(len(types)):
for j in range(i):
ci = np.ones(1, types[i])
cj = np.ones(1, types[j])
[resi, resj] = pu.as_series([ci, cj])
assert_(resi.dtype.char == resj.dtype.char)
assert_(resj.dtype.char == types[i])
def test_trimcoef(self):
coef = [2, -1, 1, 0]
# Test exceptions
assert_raises(ValueError, pu.trimcoef, coef, -1)
# Test results
assert_equal(pu.trimcoef(coef), coef[:-1])
assert_equal(pu.trimcoef(coef, 1), coef[:-3])
assert_equal(pu.trimcoef(coef, 2), [0])
class TestDomain(object):
def test_getdomain(self):
# test for real values
x = [1, 10, 3, -1]
tgt = [-1, 10]
res = pu.getdomain(x)
assert_almost_equal(res, tgt)
# test for complex values
x = [1 + 1j, 1 - 1j, 0, 2]
tgt = [-1j, 2 + 1j]
res = pu.getdomain(x)
assert_almost_equal(res, tgt)
def test_mapdomain(self):
# test for real values
dom1 = [0, 4]
dom2 = [1, 3]
tgt = dom2
res = pu. mapdomain(dom1, dom1, dom2)
assert_almost_equal(res, tgt)
# test for complex values
dom1 = [0 - 1j, 2 + 1j]
dom2 = [-2, 2]
tgt = dom2
x = dom1
res = pu.mapdomain(x, dom1, dom2)
assert_almost_equal(res, tgt)
# test for multidimensional arrays
dom1 = [0, 4]
dom2 = [1, 3]
tgt = np.array([dom2, dom2])
x = np.array([dom1, dom1])
res = pu.mapdomain(x, dom1, dom2)
assert_almost_equal(res, tgt)
# test that subtypes are preserved.
dom1 = [0, 4]
dom2 = [1, 3]
x = np.matrix([dom1, dom1])
res = pu.mapdomain(x, dom1, dom2)
assert_(isinstance(res, np.matrix))
def test_mapparms(self):
# test for real values
dom1 = [0, 4]
dom2 = [1, 3]
tgt = [1, .5]
res = pu. mapparms(dom1, dom2)
assert_almost_equal(res, tgt)
# test for complex values
dom1 = [0 - 1j, 2 + 1j]
dom2 = [-2, 2]
tgt = [-1 + 1j, 1 - 1j]
res = pu.mapparms(dom1, dom2)
assert_almost_equal(res, tgt)
if __name__ == "__main__":
run_module_suite()

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from __future__ import division, absolute_import, print_function
import numpy.polynomial as poly
from numpy.testing import run_module_suite, assert_equal
class TestStr(object):
def test_polynomial_str(self):
res = str(poly.Polynomial([0, 1]))
tgt = 'poly([0. 1.])'
assert_equal(res, tgt)
def test_chebyshev_str(self):
res = str(poly.Chebyshev([0, 1]))
tgt = 'cheb([0. 1.])'
assert_equal(res, tgt)
def test_legendre_str(self):
res = str(poly.Legendre([0, 1]))
tgt = 'leg([0. 1.])'
assert_equal(res, tgt)
def test_hermite_str(self):
res = str(poly.Hermite([0, 1]))
tgt = 'herm([0. 1.])'
assert_equal(res, tgt)
def test_hermiteE_str(self):
res = str(poly.HermiteE([0, 1]))
tgt = 'herme([0. 1.])'
assert_equal(res, tgt)
def test_laguerre_str(self):
res = str(poly.Laguerre([0, 1]))
tgt = 'lag([0. 1.])'
assert_equal(res, tgt)
class TestRepr(object):
def test_polynomial_str(self):
res = repr(poly.Polynomial([0, 1]))
tgt = 'Polynomial([0., 1.], domain=[-1, 1], window=[-1, 1])'
assert_equal(res, tgt)
def test_chebyshev_str(self):
res = repr(poly.Chebyshev([0, 1]))
tgt = 'Chebyshev([0., 1.], domain=[-1, 1], window=[-1, 1])'
assert_equal(res, tgt)
def test_legendre_repr(self):
res = repr(poly.Legendre([0, 1]))
tgt = 'Legendre([0., 1.], domain=[-1, 1], window=[-1, 1])'
assert_equal(res, tgt)
def test_hermite_repr(self):
res = repr(poly.Hermite([0, 1]))
tgt = 'Hermite([0., 1.], domain=[-1, 1], window=[-1, 1])'
assert_equal(res, tgt)
def test_hermiteE_repr(self):
res = repr(poly.HermiteE([0, 1]))
tgt = 'HermiteE([0., 1.], domain=[-1, 1], window=[-1, 1])'
assert_equal(res, tgt)
def test_laguerre_repr(self):
res = repr(poly.Laguerre([0, 1]))
tgt = 'Laguerre([0., 1.], domain=[0, 1], window=[0, 1])'
assert_equal(res, tgt)
#
if __name__ == "__main__":
run_module_suite()