Created starter files for the project.

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Batuhan Berk Başoğlu 2020-10-02 21:26:03 -04:00
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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 .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._pytesttester import PytestTester
test = PytestTester(__name__)
del PytestTester

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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.
"""
import operator
import functools
import warnings
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:
"""
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=False) 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 as e:
raise ValueError("Coefficient arrays have no common type") from e
ret = [np.array(a, copy=True, 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 , 0.001 -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, # may vary
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. -1.j , -0.6-0.6j, -0.2-0.2j, 0.2+0.2j, 0.6+0.6j, 1. +1.j ])
>>> new_z = pu.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 ]) # may vary
"""
x = np.asanyarray(x)
off, scl = mapparms(old, new)
return off + scl*x
def _nth_slice(i, ndim):
sl = [np.newaxis] * ndim
sl[i] = slice(None)
return tuple(sl)
def _vander_nd(vander_fs, points, degrees):
r"""
A generalization of the Vandermonde matrix for N dimensions
The result is built by combining the results of 1d Vandermonde matrices,
.. math::
W[i_0, \ldots, i_M, j_0, \ldots, j_N] = \prod_{k=0}^N{V_k(x_k)[i_0, \ldots, i_M, j_k]}
where
.. math::
N &= \texttt{len(points)} = \texttt{len(degrees)} = \texttt{len(vander\_fs)} \\
M &= \texttt{points[k].ndim} \\
V_k &= \texttt{vander\_fs[k]} \\
x_k &= \texttt{points[k]} \\
0 \le j_k &\le \texttt{degrees[k]}
Expanding the one-dimensional :math:`V_k` functions gives:
.. math::
W[i_0, \ldots, i_M, j_0, \ldots, j_N] = \prod_{k=0}^N{B_{k, j_k}(x_k[i_0, \ldots, i_M])}
where :math:`B_{k,m}` is the m'th basis of the polynomial construction used along
dimension :math:`k`. For a regular polynomial, :math:`B_{k, m}(x) = P_m(x) = x^m`.
Parameters
----------
vander_fs : Sequence[function(array_like, int) -> ndarray]
The 1d vander function to use for each axis, such as ``polyvander``
points : Sequence[array_like]
Arrays of point coordinates, all of the same shape. The dtypes
will be converted to either float64 or complex128 depending on
whether any of the elements are complex. Scalars are converted to
1-D arrays.
This must be the same length as `vander_fs`.
degrees : Sequence[int]
The maximum degree (inclusive) to use for each axis.
This must be the same length as `vander_fs`.
Returns
-------
vander_nd : ndarray
An array of shape ``points[0].shape + tuple(d + 1 for d in degrees)``.
"""
n_dims = len(vander_fs)
if n_dims != len(points):
raise ValueError(
f"Expected {n_dims} dimensions of sample points, got {len(points)}")
if n_dims != len(degrees):
raise ValueError(
f"Expected {n_dims} dimensions of degrees, got {len(degrees)}")
if n_dims == 0:
raise ValueError("Unable to guess a dtype or shape when no points are given")
# convert to the same shape and type
points = tuple(np.array(tuple(points), copy=False) + 0.0)
# produce the vandermonde matrix for each dimension, placing the last
# axis of each in an independent trailing axis of the output
vander_arrays = (
vander_fs[i](points[i], degrees[i])[(...,) + _nth_slice(i, n_dims)]
for i in range(n_dims)
)
# we checked this wasn't empty already, so no `initial` needed
return functools.reduce(operator.mul, vander_arrays)
def _vander_nd_flat(vander_fs, points, degrees):
"""
Like `_vander_nd`, but flattens the last ``len(degrees)`` axes into a single axis
Used to implement the public ``<type>vander<n>d`` functions.
"""
v = _vander_nd(vander_fs, points, degrees)
return v.reshape(v.shape[:-len(degrees)] + (-1,))
def _fromroots(line_f, mul_f, roots):
"""
Helper function used to implement the ``<type>fromroots`` functions.
Parameters
----------
line_f : function(float, float) -> ndarray
The ``<type>line`` function, such as ``polyline``
mul_f : function(array_like, array_like) -> ndarray
The ``<type>mul`` function, such as ``polymul``
roots :
See the ``<type>fromroots`` functions for more detail
"""
if len(roots) == 0:
return np.ones(1)
else:
[roots] = as_series([roots], trim=False)
roots.sort()
p = [line_f(-r, 1) for r in roots]
n = len(p)
while n > 1:
m, r = divmod(n, 2)
tmp = [mul_f(p[i], p[i+m]) for i in range(m)]
if r:
tmp[0] = mul_f(tmp[0], p[-1])
p = tmp
n = m
return p[0]
def _valnd(val_f, c, *args):
"""
Helper function used to implement the ``<type>val<n>d`` functions.
Parameters
----------
val_f : function(array_like, array_like, tensor: bool) -> array_like
The ``<type>val`` function, such as ``polyval``
c, args :
See the ``<type>val<n>d`` functions for more detail
"""
args = [np.asanyarray(a) for a in args]
shape0 = args[0].shape
if not all((a.shape == shape0 for a in args[1:])):
if len(args) == 3:
raise ValueError('x, y, z are incompatible')
elif len(args) == 2:
raise ValueError('x, y are incompatible')
else:
raise ValueError('ordinates are incompatible')
it = iter(args)
x0 = next(it)
# use tensor on only the first
c = val_f(x0, c)
for xi in it:
c = val_f(xi, c, tensor=False)
return c
def _gridnd(val_f, c, *args):
"""
Helper function used to implement the ``<type>grid<n>d`` functions.
Parameters
----------
val_f : function(array_like, array_like, tensor: bool) -> array_like
The ``<type>val`` function, such as ``polyval``
c, args :
See the ``<type>grid<n>d`` functions for more detail
"""
for xi in args:
c = val_f(xi, c)
return c
def _div(mul_f, c1, c2):
"""
Helper function used to implement the ``<type>div`` functions.
Implementation uses repeated subtraction of c2 multiplied by the nth basis.
For some polynomial types, a more efficient approach may be possible.
Parameters
----------
mul_f : function(array_like, array_like) -> array_like
The ``<type>mul`` function, such as ``polymul``
c1, c2 :
See the ``<type>div`` functions for more detail
"""
# c1, c2 are trimmed copies
[c1, c2] = as_series([c1, c2])
if c2[-1] == 0:
raise ZeroDivisionError()
lc1 = len(c1)
lc2 = len(c2)
if lc1 < lc2:
return c1[:1]*0, c1
elif lc2 == 1:
return c1/c2[-1], c1[:1]*0
else:
quo = np.empty(lc1 - lc2 + 1, dtype=c1.dtype)
rem = c1
for i in range(lc1 - lc2, - 1, -1):
p = mul_f([0]*i + [1], c2)
q = rem[-1]/p[-1]
rem = rem[:-1] - q*p[:-1]
quo[i] = q
return quo, trimseq(rem)
def _add(c1, c2):
""" Helper function used to implement the ``<type>add`` functions. """
# c1, c2 are trimmed copies
[c1, c2] = as_series([c1, c2])
if len(c1) > len(c2):
c1[:c2.size] += c2
ret = c1
else:
c2[:c1.size] += c1
ret = c2
return trimseq(ret)
def _sub(c1, c2):
""" Helper function used to implement the ``<type>sub`` functions. """
# c1, c2 are trimmed copies
[c1, c2] = as_series([c1, c2])
if len(c1) > len(c2):
c1[:c2.size] -= c2
ret = c1
else:
c2 = -c2
c2[:c1.size] += c1
ret = c2
return trimseq(ret)
def _fit(vander_f, x, y, deg, rcond=None, full=False, w=None):
"""
Helper function used to implement the ``<type>fit`` functions.
Parameters
----------
vander_f : function(array_like, int) -> ndarray
The 1d vander function, such as ``polyvander``
c1, c2 :
See the ``<type>fit`` functions for more detail
"""
x = np.asarray(x) + 0.0
y = np.asarray(y) + 0.0
deg = np.asarray(deg)
# check arguments.
if deg.ndim > 1 or deg.dtype.kind not in 'iu' or deg.size == 0:
raise TypeError("deg must be an int or non-empty 1-D array of int")
if deg.min() < 0:
raise ValueError("expected deg >= 0")
if x.ndim != 1:
raise TypeError("expected 1D vector for x")
if x.size == 0:
raise TypeError("expected non-empty vector for x")
if y.ndim < 1 or y.ndim > 2:
raise TypeError("expected 1D or 2D array for y")
if len(x) != len(y):
raise TypeError("expected x and y to have same length")
if deg.ndim == 0:
lmax = deg
order = lmax + 1
van = vander_f(x, lmax)
else:
deg = np.sort(deg)
lmax = deg[-1]
order = len(deg)
van = vander_f(x, lmax)[:, deg]
# set up the least squares matrices in transposed form
lhs = van.T
rhs = y.T
if w is not None:
w = np.asarray(w) + 0.0
if w.ndim != 1:
raise TypeError("expected 1D vector for w")
if len(x) != len(w):
raise TypeError("expected x and w to have same length")
# apply weights. Don't use inplace operations as they
# can cause problems with NA.
lhs = lhs * w
rhs = rhs * w
# set rcond
if rcond is None:
rcond = len(x)*np.finfo(x.dtype).eps
# Determine the norms of the design matrix columns.
if issubclass(lhs.dtype.type, np.complexfloating):
scl = np.sqrt((np.square(lhs.real) + np.square(lhs.imag)).sum(1))
else:
scl = np.sqrt(np.square(lhs).sum(1))
scl[scl == 0] = 1
# Solve the least squares problem.
c, resids, rank, s = np.linalg.lstsq(lhs.T/scl, rhs.T, rcond)
c = (c.T/scl).T
# Expand c to include non-fitted coefficients which are set to zero
if deg.ndim > 0:
if c.ndim == 2:
cc = np.zeros((lmax+1, c.shape[1]), dtype=c.dtype)
else:
cc = np.zeros(lmax+1, dtype=c.dtype)
cc[deg] = c
c = cc
# warn on rank reduction
if rank != order and not full:
msg = "The fit may be poorly conditioned"
warnings.warn(msg, RankWarning, stacklevel=2)
if full:
return c, [resids, rank, s, rcond]
else:
return c
def _pow(mul_f, c, pow, maxpower):
"""
Helper function used to implement the ``<type>pow`` functions.
Parameters
----------
vander_f : function(array_like, int) -> ndarray
The 1d vander function, such as ``polyvander``
pow, maxpower :
See the ``<type>pow`` functions for more detail
mul_f : function(array_like, array_like) -> ndarray
The ``<type>mul`` function, such as ``polymul``
"""
# c is a trimmed copy
[c] = as_series([c])
power = int(pow)
if power != pow or power < 0:
raise ValueError("Power must be a non-negative integer.")
elif maxpower is not None and power > maxpower:
raise ValueError("Power is too large")
elif power == 0:
return np.array([1], dtype=c.dtype)
elif power == 1:
return c
else:
# This can be made more efficient by using powers of two
# in the usual way.
prd = c
for i in range(2, power + 1):
prd = mul_f(prd, c)
return prd
def _deprecate_as_int(x, desc):
"""
Like `operator.index`, but emits a deprecation warning when passed a float
Parameters
----------
x : int-like, or float with integral value
Value to interpret as an integer
desc : str
description to include in any error message
Raises
------
TypeError : if x is a non-integral float or non-numeric
DeprecationWarning : if x is an integral float
"""
try:
return operator.index(x)
except TypeError as e:
# Numpy 1.17.0, 2019-03-11
try:
ix = int(x)
except TypeError:
pass
else:
if ix == x:
warnings.warn(
f"In future, this will raise TypeError, as {desc} will "
"need to be an integer not just an integral float.",
DeprecationWarning,
stacklevel=3
)
return ix
raise TypeError(f"{desc} must be an integer") from e

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

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"""Tests for chebyshev module.
"""
from functools import reduce
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_,
)
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:
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:
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:
def test_chebadd(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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)
def test_chebpow(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={j}"
c = np.arange(i + 1)
tgt = reduce(cheb.chebmul, [c]*j, np.array([1]))
res = cheb.chebpow(c, j)
assert_equal(trim(res), trim(tgt), err_msg=msg)
class TestEvaluation:
# 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 = f"At i={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:
def test_chebint(self):
# check exceptions
assert_raises(TypeError, 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(TypeError, 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:
def test_chebder(self):
# check exceptions
assert_raises(TypeError, 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:
# 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:
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:
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:
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:
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:
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)

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"""Test inter-conversion of different polynomial classes.
This tests the convert and cast methods of all the polynomial classes.
"""
import operator as op
from numbers import Number
import pytest
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_,
)
from numpy.polynomial.polyutils import RankWarning
#
# fixtures
#
classes = (
Polynomial, Legendre, Chebyshev, Laguerre,
Hermite, HermiteE
)
classids = tuple(cls.__name__ for cls in classes)
@pytest.fixture(params=classes, ids=classids)
def Poly(request):
return request.param
#
# 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 = f"Result: {p1}\nTarget: {p2}"
raise AssertionError(msg)
#
# Test conversion methods that depend on combinations of two classes.
#
Poly1 = Poly
Poly2 = Poly
def test_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 test_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))
#
# test methods that depend on one class
#
def test_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 test_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 test_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 test_bad_conditioned_fit(Poly):
x = [0., 0., 1.]
y = [1., 2., 3.]
# check RankWarning is raised
with pytest.warns(RankWarning) as record:
Poly.fit(x, y, 2)
assert record[0].message.args[0] == "The fit may be poorly conditioned"
def test_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 test_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 test_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 test_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 test_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 test_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 test_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 test_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, 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 test_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 test_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 test_roots(Poly):
d = Poly.domain * 1.25 + .25
w = Poly.window
tgt = np.linspace(d[0], d[1], 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 test_degree(Poly):
p = Poly.basis(5)
assert_equal(p.degree(), 5)
def test_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 test_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 test_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 test_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 test_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 test_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 test_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 test_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 test_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 test_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 test_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)
#
# Test class method that only exists for some classes
#
class TestInterpolate:
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)

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@ -0,0 +1,555 @@
"""Tests for hermite module.
"""
from functools import reduce
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_,
)
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:
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:
x = np.linspace(-3, 3, 100)
def test_hermadd(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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)
def test_hermpow(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={j}"
c = np.arange(i + 1)
tgt = reduce(herm.hermmul, [c]*j, np.array([1]))
res = herm.hermpow(c, j)
assert_equal(trim(res), trim(tgt), err_msg=msg)
class TestEvaluation:
# 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 = f"At i={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:
def test_hermint(self):
# check exceptions
assert_raises(TypeError, 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(TypeError, 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:
def test_hermder(self):
# check exceptions
assert_raises(TypeError, 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:
# 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:
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:
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:
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:
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)

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@ -0,0 +1,556 @@
"""Tests for hermite_e module.
"""
from functools import reduce
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_,
)
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:
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:
x = np.linspace(-3, 3, 100)
def test_hermeadd(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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)
def test_hermepow(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={j}"
c = np.arange(i + 1)
tgt = reduce(herme.hermemul, [c]*j, np.array([1]))
res = herme.hermepow(c, j)
assert_equal(trim(res), trim(tgt), err_msg=msg)
class TestEvaluation:
# 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 = f"At i={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:
def test_hermeint(self):
# check exceptions
assert_raises(TypeError, 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(TypeError, 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:
def test_hermeder(self):
# check exceptions
assert_raises(TypeError, 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:
# 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:
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:
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:
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:
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)

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@ -0,0 +1,537 @@
"""Tests for laguerre module.
"""
from functools import reduce
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_,
)
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:
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:
x = np.linspace(-3, 3, 100)
def test_lagadd(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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)
def test_lagpow(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={j}"
c = np.arange(i + 1)
tgt = reduce(lag.lagmul, [c]*j, np.array([1]))
res = lag.lagpow(c, j)
assert_equal(trim(res), trim(tgt), err_msg=msg)
class TestEvaluation:
# 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 = f"At i={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:
def test_lagint(self):
# check exceptions
assert_raises(TypeError, 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(TypeError, 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:
def test_lagder(self):
# check exceptions
assert_raises(TypeError, 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:
# 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:
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:
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:
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:
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)

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@ -0,0 +1,556 @@
"""Tests for legendre module.
"""
from functools import reduce
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_,
)
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:
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:
x = np.linspace(-1, 1, 100)
def test_legadd(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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)
def test_legpow(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={j}"
c = np.arange(i + 1)
tgt = reduce(leg.legmul, [c]*j, np.array([1]))
res = leg.legpow(c, j)
assert_equal(trim(res), trim(tgt), err_msg=msg)
class TestEvaluation:
# 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 = f"At i={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:
def test_legint(self):
# check exceptions
assert_raises(TypeError, 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(TypeError, 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:
def test_legder(self):
# check exceptions
assert_raises(TypeError, 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:
# 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:
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:
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:
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:
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)

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@ -0,0 +1,593 @@
"""Tests for polynomial module.
"""
from functools import reduce
import numpy as np
import numpy.polynomial.polynomial as poly
from numpy.testing import (
assert_almost_equal, assert_raises, assert_equal, assert_,
assert_warns, assert_array_equal, assert_raises_regex)
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:
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:
def test_polyadd(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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 = f"At i={i}, j={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)
def test_polypow(self):
for i in range(5):
for j in range(5):
msg = f"At i={i}, j={j}"
c = np.arange(i + 1)
tgt = reduce(poly.polymul, [c]*j, np.array([1]))
res = poly.polypow(c, j)
assert_equal(trim(res), trim(tgt), err_msg=msg)
class TestEvaluation:
# 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)
#check masked arrays are processed correctly
mask = [False, True, False]
mx = np.ma.array([1, 2, 3], mask=mask)
res = np.polyval([7, 5, 3], mx)
assert_array_equal(res.mask, mask)
#check subtypes of ndarray are preserved
class C(np.ndarray):
pass
cx = np.array([1, 2, 3]).view(C)
assert_equal(type(np.polyval([2, 3, 4], cx)), C)
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_regex(ValueError, 'incompatible',
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_regex(ValueError, 'incompatible',
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:
def test_polyint(self):
# check exceptions
assert_raises(TypeError, 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(TypeError, poly.polyint, [0], axis=.5)
with assert_warns(DeprecationWarning):
poly.polyint([1, 1], 1.)
# 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:
def test_polyder(self):
# check exceptions
assert_raises(TypeError, 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:
# 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:
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:
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])

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"""Tests for polyutils module.
"""
import numpy as np
import numpy.polynomial.polyutils as pu
from numpy.testing import (
assert_almost_equal, assert_raises, assert_equal, assert_,
)
class TestMisc:
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:
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.
class MyNDArray(np.ndarray):
pass
dom1 = [0, 4]
dom2 = [1, 3]
x = np.array([dom1, dom1]).view(MyNDArray)
res = pu.mapdomain(x, dom1, dom2)
assert_(isinstance(res, MyNDArray))
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)

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import numpy.polynomial as poly
from numpy.testing import assert_equal
class TestStr:
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:
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)
class TestLatexRepr:
"""Test the latex repr used by Jupyter"""
def as_latex(self, obj):
# right now we ignore the formatting of scalars in our tests, since
# it makes them too verbose. Ideally, the formatting of scalars will
# be fixed such that tests below continue to pass
obj._repr_latex_scalar = lambda x: str(x)
try:
return obj._repr_latex_()
finally:
del obj._repr_latex_scalar
def test_simple_polynomial(self):
# default input
p = poly.Polynomial([1, 2, 3])
assert_equal(self.as_latex(p),
r'$x \mapsto 1.0 + 2.0\,x + 3.0\,x^{2}$')
# translated input
p = poly.Polynomial([1, 2, 3], domain=[-2, 0])
assert_equal(self.as_latex(p),
r'$x \mapsto 1.0 + 2.0\,\left(1.0 + x\right) + 3.0\,\left(1.0 + x\right)^{2}$')
# scaled input
p = poly.Polynomial([1, 2, 3], domain=[-0.5, 0.5])
assert_equal(self.as_latex(p),
r'$x \mapsto 1.0 + 2.0\,\left(2.0x\right) + 3.0\,\left(2.0x\right)^{2}$')
# affine input
p = poly.Polynomial([1, 2, 3], domain=[-1, 0])
assert_equal(self.as_latex(p),
r'$x \mapsto 1.0 + 2.0\,\left(1.0 + 2.0x\right) + 3.0\,\left(1.0 + 2.0x\right)^{2}$')
def test_basis_func(self):
p = poly.Chebyshev([1, 2, 3])
assert_equal(self.as_latex(p),
r'$x \mapsto 1.0\,{T}_{0}(x) + 2.0\,{T}_{1}(x) + 3.0\,{T}_{2}(x)$')
# affine input - check no surplus parens are added
p = poly.Chebyshev([1, 2, 3], domain=[-1, 0])
assert_equal(self.as_latex(p),
r'$x \mapsto 1.0\,{T}_{0}(1.0 + 2.0x) + 2.0\,{T}_{1}(1.0 + 2.0x) + 3.0\,{T}_{2}(1.0 + 2.0x)$')
def test_multichar_basis_func(self):
p = poly.HermiteE([1, 2, 3])
assert_equal(self.as_latex(p),
r'$x \mapsto 1.0\,{He}_{0}(x) + 2.0\,{He}_{1}(x) + 3.0\,{He}_{2}(x)$')