Fixed database typo and removed unnecessary class identifier.

This commit is contained in:
Batuhan Berk Başoğlu 2020-10-14 10:10:37 -04:00
parent 00ad49a143
commit 45fb349a7d
5098 changed files with 952558 additions and 85 deletions

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"""
=========================================================
Legacy discrete Fourier transforms (:mod:`scipy.fftpack`)
=========================================================
.. warning::
This submodule is now considered legacy, new code should use
:mod:`scipy.fft`.
Fast Fourier Transforms (FFTs)
==============================
.. autosummary::
:toctree: generated/
fft - Fast (discrete) Fourier Transform (FFT)
ifft - Inverse FFT
fft2 - 2-D FFT
ifft2 - 2-D inverse FFT
fftn - N-D FFT
ifftn - N-D inverse FFT
rfft - FFT of strictly real-valued sequence
irfft - Inverse of rfft
dct - Discrete cosine transform
idct - Inverse discrete cosine transform
dctn - N-D Discrete cosine transform
idctn - N-D Inverse discrete cosine transform
dst - Discrete sine transform
idst - Inverse discrete sine transform
dstn - N-D Discrete sine transform
idstn - N-D Inverse discrete sine transform
Differential and pseudo-differential operators
==============================================
.. autosummary::
:toctree: generated/
diff - Differentiation and integration of periodic sequences
tilbert - Tilbert transform: cs_diff(x,h,h)
itilbert - Inverse Tilbert transform: sc_diff(x,h,h)
hilbert - Hilbert transform: cs_diff(x,inf,inf)
ihilbert - Inverse Hilbert transform: sc_diff(x,inf,inf)
cs_diff - cosh/sinh pseudo-derivative of periodic sequences
sc_diff - sinh/cosh pseudo-derivative of periodic sequences
ss_diff - sinh/sinh pseudo-derivative of periodic sequences
cc_diff - cosh/cosh pseudo-derivative of periodic sequences
shift - Shift periodic sequences
Helper functions
================
.. autosummary::
:toctree: generated/
fftshift - Shift the zero-frequency component to the center of the spectrum
ifftshift - The inverse of `fftshift`
fftfreq - Return the Discrete Fourier Transform sample frequencies
rfftfreq - DFT sample frequencies (for usage with rfft, irfft)
next_fast_len - Find the optimal length to zero-pad an FFT for speed
Note that ``fftshift``, ``ifftshift`` and ``fftfreq`` are numpy functions
exposed by ``fftpack``; importing them from ``numpy`` should be preferred.
Convolutions (:mod:`scipy.fftpack.convolve`)
============================================
.. module:: scipy.fftpack.convolve
.. autosummary::
:toctree: generated/
convolve
convolve_z
init_convolution_kernel
destroy_convolve_cache
"""
__all__ = ['fft','ifft','fftn','ifftn','rfft','irfft',
'fft2','ifft2',
'diff',
'tilbert','itilbert','hilbert','ihilbert',
'sc_diff','cs_diff','cc_diff','ss_diff',
'shift',
'fftfreq', 'rfftfreq',
'fftshift', 'ifftshift',
'next_fast_len',
'dct', 'idct', 'dst', 'idst', 'dctn', 'idctn', 'dstn', 'idstn'
]
from .basic import *
from .pseudo_diffs import *
from .helper import *
from .realtransforms import *
from scipy._lib._testutils import PytestTester
test = PytestTester(__name__)
del PytestTester

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"""
Discrete Fourier Transforms - basic.py
"""
# Created by Pearu Peterson, August,September 2002
__all__ = ['fft','ifft','fftn','ifftn','rfft','irfft',
'fft2','ifft2']
from scipy.fft import _pocketfft
from .helper import _good_shape
def fft(x, n=None, axis=-1, overwrite_x=False):
"""
Return discrete Fourier transform of real or complex sequence.
The returned complex array contains ``y(0), y(1),..., y(n-1)``, where
``y(j) = (x * exp(-2*pi*sqrt(-1)*j*np.arange(n)/n)).sum()``.
Parameters
----------
x : array_like
Array to Fourier transform.
n : int, optional
Length of the Fourier transform. If ``n < x.shape[axis]``, `x` is
truncated. If ``n > x.shape[axis]``, `x` is zero-padded. The
default results in ``n = x.shape[axis]``.
axis : int, optional
Axis along which the fft's are computed; the default is over the
last axis (i.e., ``axis=-1``).
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed; the default is False.
Returns
-------
z : complex ndarray
with the elements::
[y(0),y(1),..,y(n/2),y(1-n/2),...,y(-1)] if n is even
[y(0),y(1),..,y((n-1)/2),y(-(n-1)/2),...,y(-1)] if n is odd
where::
y(j) = sum[k=0..n-1] x[k] * exp(-sqrt(-1)*j*k* 2*pi/n), j = 0..n-1
See Also
--------
ifft : Inverse FFT
rfft : FFT of a real sequence
Notes
-----
The packing of the result is "standard": If ``A = fft(a, n)``, then
``A[0]`` contains the zero-frequency term, ``A[1:n/2]`` contains the
positive-frequency terms, and ``A[n/2:]`` contains the negative-frequency
terms, in order of decreasingly negative frequency. So ,for an 8-point
transform, the frequencies of the result are [0, 1, 2, 3, -4, -3, -2, -1].
To rearrange the fft output so that the zero-frequency component is
centered, like [-4, -3, -2, -1, 0, 1, 2, 3], use `fftshift`.
Both single and double precision routines are implemented. Half precision
inputs will be converted to single precision. Non-floating-point inputs
will be converted to double precision. Long-double precision inputs are
not supported.
This function is most efficient when `n` is a power of two, and least
efficient when `n` is prime.
Note that if ``x`` is real-valued, then ``A[j] == A[n-j].conjugate()``.
If ``x`` is real-valued and ``n`` is even, then ``A[n/2]`` is real.
If the data type of `x` is real, a "real FFT" algorithm is automatically
used, which roughly halves the computation time. To increase efficiency
a little further, use `rfft`, which does the same calculation, but only
outputs half of the symmetrical spectrum. If the data is both real and
symmetrical, the `dct` can again double the efficiency by generating
half of the spectrum from half of the signal.
Examples
--------
>>> from scipy.fftpack import fft, ifft
>>> x = np.arange(5)
>>> np.allclose(fft(ifft(x)), x, atol=1e-15) # within numerical accuracy.
True
"""
return _pocketfft.fft(x, n, axis, None, overwrite_x)
def ifft(x, n=None, axis=-1, overwrite_x=False):
"""
Return discrete inverse Fourier transform of real or complex sequence.
The returned complex array contains ``y(0), y(1),..., y(n-1)``, where
``y(j) = (x * exp(2*pi*sqrt(-1)*j*np.arange(n)/n)).mean()``.
Parameters
----------
x : array_like
Transformed data to invert.
n : int, optional
Length of the inverse Fourier transform. If ``n < x.shape[axis]``,
`x` is truncated. If ``n > x.shape[axis]``, `x` is zero-padded.
The default results in ``n = x.shape[axis]``.
axis : int, optional
Axis along which the ifft's are computed; the default is over the
last axis (i.e., ``axis=-1``).
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed; the default is False.
Returns
-------
ifft : ndarray of floats
The inverse discrete Fourier transform.
See Also
--------
fft : Forward FFT
Notes
-----
Both single and double precision routines are implemented. Half precision
inputs will be converted to single precision. Non-floating-point inputs
will be converted to double precision. Long-double precision inputs are
not supported.
This function is most efficient when `n` is a power of two, and least
efficient when `n` is prime.
If the data type of `x` is real, a "real IFFT" algorithm is automatically
used, which roughly halves the computation time.
Examples
--------
>>> from scipy.fftpack import fft, ifft
>>> import numpy as np
>>> x = np.arange(5)
>>> np.allclose(ifft(fft(x)), x, atol=1e-15) # within numerical accuracy.
True
"""
return _pocketfft.ifft(x, n, axis, None, overwrite_x)
def rfft(x, n=None, axis=-1, overwrite_x=False):
"""
Discrete Fourier transform of a real sequence.
Parameters
----------
x : array_like, real-valued
The data to transform.
n : int, optional
Defines the length of the Fourier transform. If `n` is not specified
(the default) then ``n = x.shape[axis]``. If ``n < x.shape[axis]``,
`x` is truncated, if ``n > x.shape[axis]``, `x` is zero-padded.
axis : int, optional
The axis along which the transform is applied. The default is the
last axis.
overwrite_x : bool, optional
If set to true, the contents of `x` can be overwritten. Default is
False.
Returns
-------
z : real ndarray
The returned real array contains::
[y(0),Re(y(1)),Im(y(1)),...,Re(y(n/2))] if n is even
[y(0),Re(y(1)),Im(y(1)),...,Re(y(n/2)),Im(y(n/2))] if n is odd
where::
y(j) = sum[k=0..n-1] x[k] * exp(-sqrt(-1)*j*k*2*pi/n)
j = 0..n-1
See Also
--------
fft, irfft, scipy.fft.rfft
Notes
-----
Within numerical accuracy, ``y == rfft(irfft(y))``.
Both single and double precision routines are implemented. Half precision
inputs will be converted to single precision. Non-floating-point inputs
will be converted to double precision. Long-double precision inputs are
not supported.
To get an output with a complex datatype, consider using the newer
function `scipy.fft.rfft`.
Examples
--------
>>> from scipy.fftpack import fft, rfft
>>> a = [9, -9, 1, 3]
>>> fft(a)
array([ 4. +0.j, 8.+12.j, 16. +0.j, 8.-12.j])
>>> rfft(a)
array([ 4., 8., 12., 16.])
"""
return _pocketfft.rfft_fftpack(x, n, axis, None, overwrite_x)
def irfft(x, n=None, axis=-1, overwrite_x=False):
"""
Return inverse discrete Fourier transform of real sequence x.
The contents of `x` are interpreted as the output of the `rfft`
function.
Parameters
----------
x : array_like
Transformed data to invert.
n : int, optional
Length of the inverse Fourier transform.
If n < x.shape[axis], x is truncated.
If n > x.shape[axis], x is zero-padded.
The default results in n = x.shape[axis].
axis : int, optional
Axis along which the ifft's are computed; the default is over
the last axis (i.e., axis=-1).
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed; the default is False.
Returns
-------
irfft : ndarray of floats
The inverse discrete Fourier transform.
See Also
--------
rfft, ifft, scipy.fft.irfft
Notes
-----
The returned real array contains::
[y(0),y(1),...,y(n-1)]
where for n is even::
y(j) = 1/n (sum[k=1..n/2-1] (x[2*k-1]+sqrt(-1)*x[2*k])
* exp(sqrt(-1)*j*k* 2*pi/n)
+ c.c. + x[0] + (-1)**(j) x[n-1])
and for n is odd::
y(j) = 1/n (sum[k=1..(n-1)/2] (x[2*k-1]+sqrt(-1)*x[2*k])
* exp(sqrt(-1)*j*k* 2*pi/n)
+ c.c. + x[0])
c.c. denotes complex conjugate of preceding expression.
For details on input parameters, see `rfft`.
To process (conjugate-symmetric) frequency-domain data with a complex
datatype, consider using the newer function `scipy.fft.irfft`.
Examples
--------
>>> from scipy.fftpack import rfft, irfft
>>> a = [1.0, 2.0, 3.0, 4.0, 5.0]
>>> irfft(a)
array([ 2.6 , -3.16405192, 1.24398433, -1.14955713, 1.46962473])
>>> irfft(rfft(a))
array([1., 2., 3., 4., 5.])
"""
return _pocketfft.irfft_fftpack(x, n, axis, None, overwrite_x)
def fftn(x, shape=None, axes=None, overwrite_x=False):
"""
Return multidimensional discrete Fourier transform.
The returned array contains::
y[j_1,..,j_d] = sum[k_1=0..n_1-1, ..., k_d=0..n_d-1]
x[k_1,..,k_d] * prod[i=1..d] exp(-sqrt(-1)*2*pi/n_i * j_i * k_i)
where d = len(x.shape) and n = x.shape.
Parameters
----------
x : array_like
The (N-D) array to transform.
shape : int or array_like of ints or None, optional
The shape of the result. If both `shape` and `axes` (see below) are
None, `shape` is ``x.shape``; if `shape` is None but `axes` is
not None, then `shape` is ``scipy.take(x.shape, axes, axis=0)``.
If ``shape[i] > x.shape[i]``, the ith dimension is padded with zeros.
If ``shape[i] < x.shape[i]``, the ith dimension is truncated to
length ``shape[i]``.
If any element of `shape` is -1, the size of the corresponding
dimension of `x` is used.
axes : int or array_like of ints or None, optional
The axes of `x` (`y` if `shape` is not None) along which the
transform is applied.
The default is over all axes.
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed. Default is False.
Returns
-------
y : complex-valued N-D NumPy array
The (N-D) DFT of the input array.
See Also
--------
ifftn
Notes
-----
If ``x`` is real-valued, then
``y[..., j_i, ...] == y[..., n_i-j_i, ...].conjugate()``.
Both single and double precision routines are implemented. Half precision
inputs will be converted to single precision. Non-floating-point inputs
will be converted to double precision. Long-double precision inputs are
not supported.
Examples
--------
>>> from scipy.fftpack import fftn, ifftn
>>> y = (-np.arange(16), 8 - np.arange(16), np.arange(16))
>>> np.allclose(y, fftn(ifftn(y)))
True
"""
shape = _good_shape(x, shape, axes)
return _pocketfft.fftn(x, shape, axes, None, overwrite_x)
def ifftn(x, shape=None, axes=None, overwrite_x=False):
"""
Return inverse multidimensional discrete Fourier transform.
The sequence can be of an arbitrary type.
The returned array contains::
y[j_1,..,j_d] = 1/p * sum[k_1=0..n_1-1, ..., k_d=0..n_d-1]
x[k_1,..,k_d] * prod[i=1..d] exp(sqrt(-1)*2*pi/n_i * j_i * k_i)
where ``d = len(x.shape)``, ``n = x.shape``, and ``p = prod[i=1..d] n_i``.
For description of parameters see `fftn`.
See Also
--------
fftn : for detailed information.
Examples
--------
>>> from scipy.fftpack import fftn, ifftn
>>> import numpy as np
>>> y = (-np.arange(16), 8 - np.arange(16), np.arange(16))
>>> np.allclose(y, ifftn(fftn(y)))
True
"""
shape = _good_shape(x, shape, axes)
return _pocketfft.ifftn(x, shape, axes, None, overwrite_x)
def fft2(x, shape=None, axes=(-2,-1), overwrite_x=False):
"""
2-D discrete Fourier transform.
Return the 2-D discrete Fourier transform of the 2-D argument
`x`.
See Also
--------
fftn : for detailed information.
Examples
--------
>>> from scipy.fftpack import fft2, ifft2
>>> y = np.mgrid[:5, :5][0]
>>> y
array([[0, 0, 0, 0, 0],
[1, 1, 1, 1, 1],
[2, 2, 2, 2, 2],
[3, 3, 3, 3, 3],
[4, 4, 4, 4, 4]])
>>> np.allclose(y, ifft2(fft2(y)))
True
"""
return fftn(x,shape,axes,overwrite_x)
def ifft2(x, shape=None, axes=(-2,-1), overwrite_x=False):
"""
2-D discrete inverse Fourier transform of real or complex sequence.
Return inverse 2-D discrete Fourier transform of
arbitrary type sequence x.
See `ifft` for more information.
See also
--------
fft2, ifft
Examples
--------
>>> from scipy.fftpack import fft2, ifft2
>>> y = np.mgrid[:5, :5][0]
>>> y
array([[0, 0, 0, 0, 0],
[1, 1, 1, 1, 1],
[2, 2, 2, 2, 2],
[3, 3, 3, 3, 3],
[4, 4, 4, 4, 4]])
>>> np.allclose(y, fft2(ifft2(y)))
True
"""
return ifftn(x,shape,axes,overwrite_x)

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import operator
from numpy.fft.helper import fftshift, ifftshift, fftfreq
import scipy.fft._pocketfft.helper as _helper
import numpy as np
__all__ = ['fftshift', 'ifftshift', 'fftfreq', 'rfftfreq', 'next_fast_len']
def rfftfreq(n, d=1.0):
"""DFT sample frequencies (for usage with rfft, irfft).
The returned float array contains the frequency bins in
cycles/unit (with zero at the start) given a window length `n` and a
sample spacing `d`::
f = [0,1,1,2,2,...,n/2-1,n/2-1,n/2]/(d*n) if n is even
f = [0,1,1,2,2,...,n/2-1,n/2-1,n/2,n/2]/(d*n) if n is odd
Parameters
----------
n : int
Window length.
d : scalar, optional
Sample spacing. Default is 1.
Returns
-------
out : ndarray
The array of length `n`, containing the sample frequencies.
Examples
--------
>>> from scipy import fftpack
>>> sig = np.array([-2, 8, 6, 4, 1, 0, 3, 5], dtype=float)
>>> sig_fft = fftpack.rfft(sig)
>>> n = sig_fft.size
>>> timestep = 0.1
>>> freq = fftpack.rfftfreq(n, d=timestep)
>>> freq
array([ 0. , 1.25, 1.25, 2.5 , 2.5 , 3.75, 3.75, 5. ])
"""
n = operator.index(n)
if n < 0:
raise ValueError("n = %s is not valid. "
"n must be a nonnegative integer." % n)
return (np.arange(1, n + 1, dtype=int) // 2) / float(n * d)
def next_fast_len(target):
"""
Find the next fast size of input data to `fft`, for zero-padding, etc.
SciPy's FFTPACK has efficient functions for radix {2, 3, 4, 5}, so this
returns the next composite of the prime factors 2, 3, and 5 which is
greater than or equal to `target`. (These are also known as 5-smooth
numbers, regular numbers, or Hamming numbers.)
Parameters
----------
target : int
Length to start searching from. Must be a positive integer.
Returns
-------
out : int
The first 5-smooth number greater than or equal to `target`.
Notes
-----
.. versionadded:: 0.18.0
Examples
--------
On a particular machine, an FFT of prime length takes 133 ms:
>>> from scipy import fftpack
>>> min_len = 10007 # prime length is worst case for speed
>>> a = np.random.randn(min_len)
>>> b = fftpack.fft(a)
Zero-padding to the next 5-smooth length reduces computation time to
211 us, a speedup of 630 times:
>>> fftpack.helper.next_fast_len(min_len)
10125
>>> b = fftpack.fft(a, 10125)
Rounding up to the next power of 2 is not optimal, taking 367 us to
compute, 1.7 times as long as the 5-smooth size:
>>> b = fftpack.fft(a, 16384)
"""
# Real transforms use regular sizes so this is backwards compatible
return _helper.good_size(target, True)
def _good_shape(x, shape, axes):
"""Ensure that shape argument is valid for scipy.fftpack
scipy.fftpack does not support len(shape) < x.ndim when axes is not given.
"""
if shape and not axes:
shape = _helper._iterable_of_int(shape, 'shape')
if len(shape) != np.ndim(x):
raise ValueError("when given, axes and shape arguments"
" have to be of the same length")
return shape

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"""
Differential and pseudo-differential operators.
"""
# Created by Pearu Peterson, September 2002
__all__ = ['diff',
'tilbert','itilbert','hilbert','ihilbert',
'cs_diff','cc_diff','sc_diff','ss_diff',
'shift']
from numpy import pi, asarray, sin, cos, sinh, cosh, tanh, iscomplexobj
from . import convolve
from scipy.fft._pocketfft.helper import _datacopied
_cache = {}
def diff(x,order=1,period=None, _cache=_cache):
"""
Return kth derivative (or integral) of a periodic sequence x.
If x_j and y_j are Fourier coefficients of periodic functions x
and y, respectively, then::
y_j = pow(sqrt(-1)*j*2*pi/period, order) * x_j
y_0 = 0 if order is not 0.
Parameters
----------
x : array_like
Input array.
order : int, optional
The order of differentiation. Default order is 1. If order is
negative, then integration is carried out under the assumption
that ``x_0 == 0``.
period : float, optional
The assumed period of the sequence. Default is ``2*pi``.
Notes
-----
If ``sum(x, axis=0) = 0`` then ``diff(diff(x, k), -k) == x`` (within
numerical accuracy).
For odd order and even ``len(x)``, the Nyquist mode is taken zero.
"""
tmp = asarray(x)
if order == 0:
return tmp
if iscomplexobj(tmp):
return diff(tmp.real,order,period)+1j*diff(tmp.imag,order,period)
if period is not None:
c = 2*pi/period
else:
c = 1.0
n = len(x)
omega = _cache.get((n,order,c))
if omega is None:
if len(_cache) > 20:
while _cache:
_cache.popitem()
def kernel(k,order=order,c=c):
if k:
return pow(c*k,order)
return 0
omega = convolve.init_convolution_kernel(n,kernel,d=order,
zero_nyquist=1)
_cache[(n,order,c)] = omega
overwrite_x = _datacopied(tmp, x)
return convolve.convolve(tmp,omega,swap_real_imag=order % 2,
overwrite_x=overwrite_x)
del _cache
_cache = {}
def tilbert(x, h, period=None, _cache=_cache):
"""
Return h-Tilbert transform of a periodic sequence x.
If x_j and y_j are Fourier coefficients of periodic functions x
and y, respectively, then::
y_j = sqrt(-1)*coth(j*h*2*pi/period) * x_j
y_0 = 0
Parameters
----------
x : array_like
The input array to transform.
h : float
Defines the parameter of the Tilbert transform.
period : float, optional
The assumed period of the sequence. Default period is ``2*pi``.
Returns
-------
tilbert : ndarray
The result of the transform.
Notes
-----
If ``sum(x, axis=0) == 0`` and ``n = len(x)`` is odd, then
``tilbert(itilbert(x)) == x``.
If ``2 * pi * h / period`` is approximately 10 or larger, then
numerically ``tilbert == hilbert``
(theoretically oo-Tilbert == Hilbert).
For even ``len(x)``, the Nyquist mode of ``x`` is taken zero.
"""
tmp = asarray(x)
if iscomplexobj(tmp):
return tilbert(tmp.real, h, period) + \
1j * tilbert(tmp.imag, h, period)
if period is not None:
h = h * 2 * pi / period
n = len(x)
omega = _cache.get((n, h))
if omega is None:
if len(_cache) > 20:
while _cache:
_cache.popitem()
def kernel(k, h=h):
if k:
return 1.0/tanh(h*k)
return 0
omega = convolve.init_convolution_kernel(n, kernel, d=1)
_cache[(n,h)] = omega
overwrite_x = _datacopied(tmp, x)
return convolve.convolve(tmp,omega,swap_real_imag=1,overwrite_x=overwrite_x)
del _cache
_cache = {}
def itilbert(x,h,period=None, _cache=_cache):
"""
Return inverse h-Tilbert transform of a periodic sequence x.
If ``x_j`` and ``y_j`` are Fourier coefficients of periodic functions x
and y, respectively, then::
y_j = -sqrt(-1)*tanh(j*h*2*pi/period) * x_j
y_0 = 0
For more details, see `tilbert`.
"""
tmp = asarray(x)
if iscomplexobj(tmp):
return itilbert(tmp.real,h,period) + \
1j*itilbert(tmp.imag,h,period)
if period is not None:
h = h*2*pi/period
n = len(x)
omega = _cache.get((n,h))
if omega is None:
if len(_cache) > 20:
while _cache:
_cache.popitem()
def kernel(k,h=h):
if k:
return -tanh(h*k)
return 0
omega = convolve.init_convolution_kernel(n,kernel,d=1)
_cache[(n,h)] = omega
overwrite_x = _datacopied(tmp, x)
return convolve.convolve(tmp,omega,swap_real_imag=1,overwrite_x=overwrite_x)
del _cache
_cache = {}
def hilbert(x, _cache=_cache):
"""
Return Hilbert transform of a periodic sequence x.
If x_j and y_j are Fourier coefficients of periodic functions x
and y, respectively, then::
y_j = sqrt(-1)*sign(j) * x_j
y_0 = 0
Parameters
----------
x : array_like
The input array, should be periodic.
_cache : dict, optional
Dictionary that contains the kernel used to do a convolution with.
Returns
-------
y : ndarray
The transformed input.
See Also
--------
scipy.signal.hilbert : Compute the analytic signal, using the Hilbert
transform.
Notes
-----
If ``sum(x, axis=0) == 0`` then ``hilbert(ihilbert(x)) == x``.
For even len(x), the Nyquist mode of x is taken zero.
The sign of the returned transform does not have a factor -1 that is more
often than not found in the definition of the Hilbert transform. Note also
that `scipy.signal.hilbert` does have an extra -1 factor compared to this
function.
"""
tmp = asarray(x)
if iscomplexobj(tmp):
return hilbert(tmp.real)+1j*hilbert(tmp.imag)
n = len(x)
omega = _cache.get(n)
if omega is None:
if len(_cache) > 20:
while _cache:
_cache.popitem()
def kernel(k):
if k > 0:
return 1.0
elif k < 0:
return -1.0
return 0.0
omega = convolve.init_convolution_kernel(n,kernel,d=1)
_cache[n] = omega
overwrite_x = _datacopied(tmp, x)
return convolve.convolve(tmp,omega,swap_real_imag=1,overwrite_x=overwrite_x)
del _cache
def ihilbert(x):
"""
Return inverse Hilbert transform of a periodic sequence x.
If ``x_j`` and ``y_j`` are Fourier coefficients of periodic functions x
and y, respectively, then::
y_j = -sqrt(-1)*sign(j) * x_j
y_0 = 0
"""
return -hilbert(x)
_cache = {}
def cs_diff(x, a, b, period=None, _cache=_cache):
"""
Return (a,b)-cosh/sinh pseudo-derivative of a periodic sequence.
If ``x_j`` and ``y_j`` are Fourier coefficients of periodic functions x
and y, respectively, then::
y_j = -sqrt(-1)*cosh(j*a*2*pi/period)/sinh(j*b*2*pi/period) * x_j
y_0 = 0
Parameters
----------
x : array_like
The array to take the pseudo-derivative from.
a, b : float
Defines the parameters of the cosh/sinh pseudo-differential
operator.
period : float, optional
The period of the sequence. Default period is ``2*pi``.
Returns
-------
cs_diff : ndarray
Pseudo-derivative of periodic sequence `x`.
Notes
-----
For even len(`x`), the Nyquist mode of `x` is taken as zero.
"""
tmp = asarray(x)
if iscomplexobj(tmp):
return cs_diff(tmp.real,a,b,period) + \
1j*cs_diff(tmp.imag,a,b,period)
if period is not None:
a = a*2*pi/period
b = b*2*pi/period
n = len(x)
omega = _cache.get((n,a,b))
if omega is None:
if len(_cache) > 20:
while _cache:
_cache.popitem()
def kernel(k,a=a,b=b):
if k:
return -cosh(a*k)/sinh(b*k)
return 0
omega = convolve.init_convolution_kernel(n,kernel,d=1)
_cache[(n,a,b)] = omega
overwrite_x = _datacopied(tmp, x)
return convolve.convolve(tmp,omega,swap_real_imag=1,overwrite_x=overwrite_x)
del _cache
_cache = {}
def sc_diff(x, a, b, period=None, _cache=_cache):
"""
Return (a,b)-sinh/cosh pseudo-derivative of a periodic sequence x.
If x_j and y_j are Fourier coefficients of periodic functions x
and y, respectively, then::
y_j = sqrt(-1)*sinh(j*a*2*pi/period)/cosh(j*b*2*pi/period) * x_j
y_0 = 0
Parameters
----------
x : array_like
Input array.
a,b : float
Defines the parameters of the sinh/cosh pseudo-differential
operator.
period : float, optional
The period of the sequence x. Default is 2*pi.
Notes
-----
``sc_diff(cs_diff(x,a,b),b,a) == x``
For even ``len(x)``, the Nyquist mode of x is taken as zero.
"""
tmp = asarray(x)
if iscomplexobj(tmp):
return sc_diff(tmp.real,a,b,period) + \
1j*sc_diff(tmp.imag,a,b,period)
if period is not None:
a = a*2*pi/period
b = b*2*pi/period
n = len(x)
omega = _cache.get((n,a,b))
if omega is None:
if len(_cache) > 20:
while _cache:
_cache.popitem()
def kernel(k,a=a,b=b):
if k:
return sinh(a*k)/cosh(b*k)
return 0
omega = convolve.init_convolution_kernel(n,kernel,d=1)
_cache[(n,a,b)] = omega
overwrite_x = _datacopied(tmp, x)
return convolve.convolve(tmp,omega,swap_real_imag=1,overwrite_x=overwrite_x)
del _cache
_cache = {}
def ss_diff(x, a, b, period=None, _cache=_cache):
"""
Return (a,b)-sinh/sinh pseudo-derivative of a periodic sequence x.
If x_j and y_j are Fourier coefficients of periodic functions x
and y, respectively, then::
y_j = sinh(j*a*2*pi/period)/sinh(j*b*2*pi/period) * x_j
y_0 = a/b * x_0
Parameters
----------
x : array_like
The array to take the pseudo-derivative from.
a,b
Defines the parameters of the sinh/sinh pseudo-differential
operator.
period : float, optional
The period of the sequence x. Default is ``2*pi``.
Notes
-----
``ss_diff(ss_diff(x,a,b),b,a) == x``
"""
tmp = asarray(x)
if iscomplexobj(tmp):
return ss_diff(tmp.real,a,b,period) + \
1j*ss_diff(tmp.imag,a,b,period)
if period is not None:
a = a*2*pi/period
b = b*2*pi/period
n = len(x)
omega = _cache.get((n,a,b))
if omega is None:
if len(_cache) > 20:
while _cache:
_cache.popitem()
def kernel(k,a=a,b=b):
if k:
return sinh(a*k)/sinh(b*k)
return float(a)/b
omega = convolve.init_convolution_kernel(n,kernel)
_cache[(n,a,b)] = omega
overwrite_x = _datacopied(tmp, x)
return convolve.convolve(tmp,omega,overwrite_x=overwrite_x)
del _cache
_cache = {}
def cc_diff(x, a, b, period=None, _cache=_cache):
"""
Return (a,b)-cosh/cosh pseudo-derivative of a periodic sequence.
If x_j and y_j are Fourier coefficients of periodic functions x
and y, respectively, then::
y_j = cosh(j*a*2*pi/period)/cosh(j*b*2*pi/period) * x_j
Parameters
----------
x : array_like
The array to take the pseudo-derivative from.
a,b : float
Defines the parameters of the sinh/sinh pseudo-differential
operator.
period : float, optional
The period of the sequence x. Default is ``2*pi``.
Returns
-------
cc_diff : ndarray
Pseudo-derivative of periodic sequence `x`.
Notes
-----
``cc_diff(cc_diff(x,a,b),b,a) == x``
"""
tmp = asarray(x)
if iscomplexobj(tmp):
return cc_diff(tmp.real,a,b,period) + \
1j*cc_diff(tmp.imag,a,b,period)
if period is not None:
a = a*2*pi/period
b = b*2*pi/period
n = len(x)
omega = _cache.get((n,a,b))
if omega is None:
if len(_cache) > 20:
while _cache:
_cache.popitem()
def kernel(k,a=a,b=b):
return cosh(a*k)/cosh(b*k)
omega = convolve.init_convolution_kernel(n,kernel)
_cache[(n,a,b)] = omega
overwrite_x = _datacopied(tmp, x)
return convolve.convolve(tmp,omega,overwrite_x=overwrite_x)
del _cache
_cache = {}
def shift(x, a, period=None, _cache=_cache):
"""
Shift periodic sequence x by a: y(u) = x(u+a).
If x_j and y_j are Fourier coefficients of periodic functions x
and y, respectively, then::
y_j = exp(j*a*2*pi/period*sqrt(-1)) * x_f
Parameters
----------
x : array_like
The array to take the pseudo-derivative from.
a : float
Defines the parameters of the sinh/sinh pseudo-differential
period : float, optional
The period of the sequences x and y. Default period is ``2*pi``.
"""
tmp = asarray(x)
if iscomplexobj(tmp):
return shift(tmp.real,a,period)+1j*shift(tmp.imag,a,period)
if period is not None:
a = a*2*pi/period
n = len(x)
omega = _cache.get((n,a))
if omega is None:
if len(_cache) > 20:
while _cache:
_cache.popitem()
def kernel_real(k,a=a):
return cos(a*k)
def kernel_imag(k,a=a):
return sin(a*k)
omega_real = convolve.init_convolution_kernel(n,kernel_real,d=0,
zero_nyquist=0)
omega_imag = convolve.init_convolution_kernel(n,kernel_imag,d=1,
zero_nyquist=0)
_cache[(n,a)] = omega_real,omega_imag
else:
omega_real,omega_imag = omega
overwrite_x = _datacopied(tmp, x)
return convolve.convolve_z(tmp,omega_real,omega_imag,
overwrite_x=overwrite_x)
del _cache

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@ -0,0 +1,588 @@
"""
Real spectrum transforms (DCT, DST, MDCT)
"""
__all__ = ['dct', 'idct', 'dst', 'idst', 'dctn', 'idctn', 'dstn', 'idstn']
from scipy.fft import _pocketfft
from .helper import _good_shape
_inverse_typemap = {1: 1, 2: 3, 3: 2, 4: 4}
def dctn(x, type=2, shape=None, axes=None, norm=None, overwrite_x=False):
"""
Return multidimensional Discrete Cosine Transform along the specified axes.
Parameters
----------
x : array_like
The input array.
type : {1, 2, 3, 4}, optional
Type of the DCT (see Notes). Default type is 2.
shape : int or array_like of ints or None, optional
The shape of the result. If both `shape` and `axes` (see below) are
None, `shape` is ``x.shape``; if `shape` is None but `axes` is
not None, then `shape` is ``scipy.take(x.shape, axes, axis=0)``.
If ``shape[i] > x.shape[i]``, the ith dimension is padded with zeros.
If ``shape[i] < x.shape[i]``, the ith dimension is truncated to
length ``shape[i]``.
If any element of `shape` is -1, the size of the corresponding
dimension of `x` is used.
axes : int or array_like of ints or None, optional
Axes along which the DCT is computed.
The default is over all axes.
norm : {None, 'ortho'}, optional
Normalization mode (see Notes). Default is None.
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed; the default is False.
Returns
-------
y : ndarray of real
The transformed input array.
See Also
--------
idctn : Inverse multidimensional DCT
Notes
-----
For full details of the DCT types and normalization modes, as well as
references, see `dct`.
Examples
--------
>>> from scipy.fftpack import dctn, idctn
>>> y = np.random.randn(16, 16)
>>> np.allclose(y, idctn(dctn(y, norm='ortho'), norm='ortho'))
True
"""
shape = _good_shape(x, shape, axes)
return _pocketfft.dctn(x, type, shape, axes, norm, overwrite_x)
def idctn(x, type=2, shape=None, axes=None, norm=None, overwrite_x=False):
"""
Return multidimensional Discrete Cosine Transform along the specified axes.
Parameters
----------
x : array_like
The input array.
type : {1, 2, 3, 4}, optional
Type of the DCT (see Notes). Default type is 2.
shape : int or array_like of ints or None, optional
The shape of the result. If both `shape` and `axes` (see below) are
None, `shape` is ``x.shape``; if `shape` is None but `axes` is
not None, then `shape` is ``scipy.take(x.shape, axes, axis=0)``.
If ``shape[i] > x.shape[i]``, the ith dimension is padded with zeros.
If ``shape[i] < x.shape[i]``, the ith dimension is truncated to
length ``shape[i]``.
If any element of `shape` is -1, the size of the corresponding
dimension of `x` is used.
axes : int or array_like of ints or None, optional
Axes along which the IDCT is computed.
The default is over all axes.
norm : {None, 'ortho'}, optional
Normalization mode (see Notes). Default is None.
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed; the default is False.
Returns
-------
y : ndarray of real
The transformed input array.
See Also
--------
dctn : multidimensional DCT
Notes
-----
For full details of the IDCT types and normalization modes, as well as
references, see `idct`.
Examples
--------
>>> from scipy.fftpack import dctn, idctn
>>> y = np.random.randn(16, 16)
>>> np.allclose(y, idctn(dctn(y, norm='ortho'), norm='ortho'))
True
"""
type = _inverse_typemap[type]
shape = _good_shape(x, shape, axes)
return _pocketfft.dctn(x, type, shape, axes, norm, overwrite_x)
def dstn(x, type=2, shape=None, axes=None, norm=None, overwrite_x=False):
"""
Return multidimensional Discrete Sine Transform along the specified axes.
Parameters
----------
x : array_like
The input array.
type : {1, 2, 3, 4}, optional
Type of the DST (see Notes). Default type is 2.
shape : int or array_like of ints or None, optional
The shape of the result. If both `shape` and `axes` (see below) are
None, `shape` is ``x.shape``; if `shape` is None but `axes` is
not None, then `shape` is ``scipy.take(x.shape, axes, axis=0)``.
If ``shape[i] > x.shape[i]``, the ith dimension is padded with zeros.
If ``shape[i] < x.shape[i]``, the ith dimension is truncated to
length ``shape[i]``.
If any element of `shape` is -1, the size of the corresponding
dimension of `x` is used.
axes : int or array_like of ints or None, optional
Axes along which the DCT is computed.
The default is over all axes.
norm : {None, 'ortho'}, optional
Normalization mode (see Notes). Default is None.
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed; the default is False.
Returns
-------
y : ndarray of real
The transformed input array.
See Also
--------
idstn : Inverse multidimensional DST
Notes
-----
For full details of the DST types and normalization modes, as well as
references, see `dst`.
Examples
--------
>>> from scipy.fftpack import dstn, idstn
>>> y = np.random.randn(16, 16)
>>> np.allclose(y, idstn(dstn(y, norm='ortho'), norm='ortho'))
True
"""
shape = _good_shape(x, shape, axes)
return _pocketfft.dstn(x, type, shape, axes, norm, overwrite_x)
def idstn(x, type=2, shape=None, axes=None, norm=None, overwrite_x=False):
"""
Return multidimensional Discrete Sine Transform along the specified axes.
Parameters
----------
x : array_like
The input array.
type : {1, 2, 3, 4}, optional
Type of the DST (see Notes). Default type is 2.
shape : int or array_like of ints or None, optional
The shape of the result. If both `shape` and `axes` (see below) are
None, `shape` is ``x.shape``; if `shape` is None but `axes` is
not None, then `shape` is ``scipy.take(x.shape, axes, axis=0)``.
If ``shape[i] > x.shape[i]``, the ith dimension is padded with zeros.
If ``shape[i] < x.shape[i]``, the ith dimension is truncated to
length ``shape[i]``.
If any element of `shape` is -1, the size of the corresponding
dimension of `x` is used.
axes : int or array_like of ints or None, optional
Axes along which the IDST is computed.
The default is over all axes.
norm : {None, 'ortho'}, optional
Normalization mode (see Notes). Default is None.
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed; the default is False.
Returns
-------
y : ndarray of real
The transformed input array.
See Also
--------
dstn : multidimensional DST
Notes
-----
For full details of the IDST types and normalization modes, as well as
references, see `idst`.
Examples
--------
>>> from scipy.fftpack import dstn, idstn
>>> y = np.random.randn(16, 16)
>>> np.allclose(y, idstn(dstn(y, norm='ortho'), norm='ortho'))
True
"""
type = _inverse_typemap[type]
shape = _good_shape(x, shape, axes)
return _pocketfft.dstn(x, type, shape, axes, norm, overwrite_x)
def dct(x, type=2, n=None, axis=-1, norm=None, overwrite_x=False):
r"""
Return the Discrete Cosine Transform of arbitrary type sequence x.
Parameters
----------
x : array_like
The input array.
type : {1, 2, 3, 4}, optional
Type of the DCT (see Notes). Default type is 2.
n : int, optional
Length of the transform. If ``n < x.shape[axis]``, `x` is
truncated. If ``n > x.shape[axis]``, `x` is zero-padded. The
default results in ``n = x.shape[axis]``.
axis : int, optional
Axis along which the dct is computed; the default is over the
last axis (i.e., ``axis=-1``).
norm : {None, 'ortho'}, optional
Normalization mode (see Notes). Default is None.
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed; the default is False.
Returns
-------
y : ndarray of real
The transformed input array.
See Also
--------
idct : Inverse DCT
Notes
-----
For a single dimension array ``x``, ``dct(x, norm='ortho')`` is equal to
MATLAB ``dct(x)``.
There are, theoretically, 8 types of the DCT, only the first 4 types are
implemented in scipy. 'The' DCT generally refers to DCT type 2, and 'the'
Inverse DCT generally refers to DCT type 3.
**Type I**
There are several definitions of the DCT-I; we use the following
(for ``norm=None``)
.. math::
y_k = x_0 + (-1)^k x_{N-1} + 2 \sum_{n=1}^{N-2} x_n \cos\left(
\frac{\pi k n}{N-1} \right)
If ``norm='ortho'``, ``x[0]`` and ``x[N-1]`` are multiplied by a scaling
factor of :math:`\sqrt{2}`, and ``y[k]`` is multiplied by a scaling factor
``f``
.. math::
f = \begin{cases}
\frac{1}{2}\sqrt{\frac{1}{N-1}} & \text{if }k=0\text{ or }N-1, \\
\frac{1}{2}\sqrt{\frac{2}{N-1}} & \text{otherwise} \end{cases}
.. versionadded:: 1.2.0
Orthonormalization in DCT-I.
.. note::
The DCT-I is only supported for input size > 1.
**Type II**
There are several definitions of the DCT-II; we use the following
(for ``norm=None``)
.. math::
y_k = 2 \sum_{n=0}^{N-1} x_n \cos\left(\frac{\pi k(2n+1)}{2N} \right)
If ``norm='ortho'``, ``y[k]`` is multiplied by a scaling factor ``f``
.. math::
f = \begin{cases}
\sqrt{\frac{1}{4N}} & \text{if }k=0, \\
\sqrt{\frac{1}{2N}} & \text{otherwise} \end{cases}
which makes the corresponding matrix of coefficients orthonormal
(``O @ O.T = np.eye(N)``).
**Type III**
There are several definitions, we use the following (for ``norm=None``)
.. math::
y_k = x_0 + 2 \sum_{n=1}^{N-1} x_n \cos\left(\frac{\pi(2k+1)n}{2N}\right)
or, for ``norm='ortho'``
.. math::
y_k = \frac{x_0}{\sqrt{N}} + \sqrt{\frac{2}{N}} \sum_{n=1}^{N-1} x_n
\cos\left(\frac{\pi(2k+1)n}{2N}\right)
The (unnormalized) DCT-III is the inverse of the (unnormalized) DCT-II, up
to a factor `2N`. The orthonormalized DCT-III is exactly the inverse of
the orthonormalized DCT-II.
**Type IV**
There are several definitions of the DCT-IV; we use the following
(for ``norm=None``)
.. math::
y_k = 2 \sum_{n=0}^{N-1} x_n \cos\left(\frac{\pi(2k+1)(2n+1)}{4N} \right)
If ``norm='ortho'``, ``y[k]`` is multiplied by a scaling factor ``f``
.. math::
f = \frac{1}{\sqrt{2N}}
.. versionadded:: 1.2.0
Support for DCT-IV.
References
----------
.. [1] 'A Fast Cosine Transform in One and Two Dimensions', by J.
Makhoul, `IEEE Transactions on acoustics, speech and signal
processing` vol. 28(1), pp. 27-34,
:doi:`10.1109/TASSP.1980.1163351` (1980).
.. [2] Wikipedia, "Discrete cosine transform",
https://en.wikipedia.org/wiki/Discrete_cosine_transform
Examples
--------
The Type 1 DCT is equivalent to the FFT (though faster) for real,
even-symmetrical inputs. The output is also real and even-symmetrical.
Half of the FFT input is used to generate half of the FFT output:
>>> from scipy.fftpack import fft, dct
>>> fft(np.array([4., 3., 5., 10., 5., 3.])).real
array([ 30., -8., 6., -2., 6., -8.])
>>> dct(np.array([4., 3., 5., 10.]), 1)
array([ 30., -8., 6., -2.])
"""
return _pocketfft.dct(x, type, n, axis, norm, overwrite_x)
def idct(x, type=2, n=None, axis=-1, norm=None, overwrite_x=False):
"""
Return the Inverse Discrete Cosine Transform of an arbitrary type sequence.
Parameters
----------
x : array_like
The input array.
type : {1, 2, 3, 4}, optional
Type of the DCT (see Notes). Default type is 2.
n : int, optional
Length of the transform. If ``n < x.shape[axis]``, `x` is
truncated. If ``n > x.shape[axis]``, `x` is zero-padded. The
default results in ``n = x.shape[axis]``.
axis : int, optional
Axis along which the idct is computed; the default is over the
last axis (i.e., ``axis=-1``).
norm : {None, 'ortho'}, optional
Normalization mode (see Notes). Default is None.
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed; the default is False.
Returns
-------
idct : ndarray of real
The transformed input array.
See Also
--------
dct : Forward DCT
Notes
-----
For a single dimension array `x`, ``idct(x, norm='ortho')`` is equal to
MATLAB ``idct(x)``.
'The' IDCT is the IDCT of type 2, which is the same as DCT of type 3.
IDCT of type 1 is the DCT of type 1, IDCT of type 2 is the DCT of type
3, and IDCT of type 3 is the DCT of type 2. IDCT of type 4 is the DCT
of type 4. For the definition of these types, see `dct`.
Examples
--------
The Type 1 DCT is equivalent to the DFT for real, even-symmetrical
inputs. The output is also real and even-symmetrical. Half of the IFFT
input is used to generate half of the IFFT output:
>>> from scipy.fftpack import ifft, idct
>>> ifft(np.array([ 30., -8., 6., -2., 6., -8.])).real
array([ 4., 3., 5., 10., 5., 3.])
>>> idct(np.array([ 30., -8., 6., -2.]), 1) / 6
array([ 4., 3., 5., 10.])
"""
type = _inverse_typemap[type]
return _pocketfft.dct(x, type, n, axis, norm, overwrite_x)
def dst(x, type=2, n=None, axis=-1, norm=None, overwrite_x=False):
r"""
Return the Discrete Sine Transform of arbitrary type sequence x.
Parameters
----------
x : array_like
The input array.
type : {1, 2, 3, 4}, optional
Type of the DST (see Notes). Default type is 2.
n : int, optional
Length of the transform. If ``n < x.shape[axis]``, `x` is
truncated. If ``n > x.shape[axis]``, `x` is zero-padded. The
default results in ``n = x.shape[axis]``.
axis : int, optional
Axis along which the dst is computed; the default is over the
last axis (i.e., ``axis=-1``).
norm : {None, 'ortho'}, optional
Normalization mode (see Notes). Default is None.
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed; the default is False.
Returns
-------
dst : ndarray of reals
The transformed input array.
See Also
--------
idst : Inverse DST
Notes
-----
For a single dimension array ``x``.
There are, theoretically, 8 types of the DST for different combinations of
even/odd boundary conditions and boundary off sets [1]_, only the first
4 types are implemented in scipy.
**Type I**
There are several definitions of the DST-I; we use the following
for ``norm=None``. DST-I assumes the input is odd around `n=-1` and `n=N`.
.. math::
y_k = 2 \sum_{n=0}^{N-1} x_n \sin\left(\frac{\pi(k+1)(n+1)}{N+1}\right)
Note that the DST-I is only supported for input size > 1.
The (unnormalized) DST-I is its own inverse, up to a factor `2(N+1)`.
The orthonormalized DST-I is exactly its own inverse.
**Type II**
There are several definitions of the DST-II; we use the following for
``norm=None``. DST-II assumes the input is odd around `n=-1/2` and
`n=N-1/2`; the output is odd around :math:`k=-1` and even around `k=N-1`
.. math::
y_k = 2 \sum_{n=0}^{N-1} x_n \sin\left(\frac{\pi(k+1)(2n+1)}{2N}\right)
if ``norm='ortho'``, ``y[k]`` is multiplied by a scaling factor ``f``
.. math::
f = \begin{cases}
\sqrt{\frac{1}{4N}} & \text{if }k = 0, \\
\sqrt{\frac{1}{2N}} & \text{otherwise} \end{cases}
**Type III**
There are several definitions of the DST-III, we use the following (for
``norm=None``). DST-III assumes the input is odd around `n=-1` and even
around `n=N-1`
.. math::
y_k = (-1)^k x_{N-1} + 2 \sum_{n=0}^{N-2} x_n \sin\left(
\frac{\pi(2k+1)(n+1)}{2N}\right)
The (unnormalized) DST-III is the inverse of the (unnormalized) DST-II, up
to a factor `2N`. The orthonormalized DST-III is exactly the inverse of the
orthonormalized DST-II.
.. versionadded:: 0.11.0
**Type IV**
There are several definitions of the DST-IV, we use the following (for
``norm=None``). DST-IV assumes the input is odd around `n=-0.5` and even
around `n=N-0.5`
.. math::
y_k = 2 \sum_{n=0}^{N-1} x_n \sin\left(\frac{\pi(2k+1)(2n+1)}{4N}\right)
The (unnormalized) DST-IV is its own inverse, up to a factor `2N`. The
orthonormalized DST-IV is exactly its own inverse.
.. versionadded:: 1.2.0
Support for DST-IV.
References
----------
.. [1] Wikipedia, "Discrete sine transform",
https://en.wikipedia.org/wiki/Discrete_sine_transform
"""
return _pocketfft.dst(x, type, n, axis, norm, overwrite_x)
def idst(x, type=2, n=None, axis=-1, norm=None, overwrite_x=False):
"""
Return the Inverse Discrete Sine Transform of an arbitrary type sequence.
Parameters
----------
x : array_like
The input array.
type : {1, 2, 3, 4}, optional
Type of the DST (see Notes). Default type is 2.
n : int, optional
Length of the transform. If ``n < x.shape[axis]``, `x` is
truncated. If ``n > x.shape[axis]``, `x` is zero-padded. The
default results in ``n = x.shape[axis]``.
axis : int, optional
Axis along which the idst is computed; the default is over the
last axis (i.e., ``axis=-1``).
norm : {None, 'ortho'}, optional
Normalization mode (see Notes). Default is None.
overwrite_x : bool, optional
If True, the contents of `x` can be destroyed; the default is False.
Returns
-------
idst : ndarray of real
The transformed input array.
See Also
--------
dst : Forward DST
Notes
-----
'The' IDST is the IDST of type 2, which is the same as DST of type 3.
IDST of type 1 is the DST of type 1, IDST of type 2 is the DST of type
3, and IDST of type 3 is the DST of type 2. For the definition of these
types, see `dst`.
.. versionadded:: 0.11.0
"""
type = _inverse_typemap[type]
return _pocketfft.dst(x, type, n, axis, norm, overwrite_x)

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# Created by Pearu Peterson, August 2002
def configuration(parent_package='',top_path=None):
from numpy.distutils.misc_util import Configuration
config = Configuration('fftpack',parent_package, top_path)
config.add_data_dir('tests')
config.add_extension('convolve', sources=['convolve.c'])
return config
if __name__ == '__main__':
from numpy.distutils.core import setup
setup(**configuration(top_path='').todict())

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CC = gcc
LD = gcc
fftw_single: fftw_dct.c
$(CC) -W -Wall -DDCT_TEST_USE_SINGLE $< -o $@ -lfftw3f
fftw_double: fftw_dct.c
$(CC) -W -Wall $< -o $@ -lfftw3
clean:
rm -f fftw_single
rm -f fftw_double
rm -f *.o

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#include <stdlib.h>
#include <stdio.h>
#include <fftw3.h>
#if DCT_TEST_PRECISION == 1
typedef float float_prec;
#define PF "%.7f"
#define FFTW_PLAN fftwf_plan
#define FFTW_MALLOC fftwf_malloc
#define FFTW_FREE fftwf_free
#define FFTW_PLAN_CREATE fftwf_plan_r2r_1d
#define FFTW_EXECUTE fftwf_execute
#define FFTW_DESTROY_PLAN fftwf_destroy_plan
#define FFTW_CLEANUP fftwf_cleanup
#elif DCT_TEST_PRECISION == 2
typedef double float_prec;
#define PF "%.18f"
#define FFTW_PLAN fftw_plan
#define FFTW_MALLOC fftw_malloc
#define FFTW_FREE fftw_free
#define FFTW_PLAN_CREATE fftw_plan_r2r_1d
#define FFTW_EXECUTE fftw_execute
#define FFTW_DESTROY_PLAN fftw_destroy_plan
#define FFTW_CLEANUP fftw_cleanup
#elif DCT_TEST_PRECISION == 3
typedef long double float_prec;
#define PF "%.18Lf"
#define FFTW_PLAN fftwl_plan
#define FFTW_MALLOC fftwl_malloc
#define FFTW_FREE fftwl_free
#define FFTW_PLAN_CREATE fftwl_plan_r2r_1d
#define FFTW_EXECUTE fftwl_execute
#define FFTW_DESTROY_PLAN fftwl_destroy_plan
#define FFTW_CLEANUP fftwl_cleanup
#else
#error DCT_TEST_PRECISION must be a number 1-3
#endif
enum type {
DCT_I = 1,
DCT_II = 2,
DCT_III = 3,
DCT_IV = 4,
DST_I = 5,
DST_II = 6,
DST_III = 7,
DST_IV = 8,
};
int gen(int type, int sz)
{
float_prec *a, *b;
FFTW_PLAN p;
int i, tp;
a = FFTW_MALLOC(sizeof(*a) * sz);
if (a == NULL) {
fprintf(stderr, "failure\n");
exit(EXIT_FAILURE);
}
b = FFTW_MALLOC(sizeof(*b) * sz);
if (b == NULL) {
fprintf(stderr, "failure\n");
exit(EXIT_FAILURE);
}
switch(type) {
case DCT_I:
tp = FFTW_REDFT00;
break;
case DCT_II:
tp = FFTW_REDFT10;
break;
case DCT_III:
tp = FFTW_REDFT01;
break;
case DCT_IV:
tp = FFTW_REDFT11;
break;
case DST_I:
tp = FFTW_RODFT00;
break;
case DST_II:
tp = FFTW_RODFT10;
break;
case DST_III:
tp = FFTW_RODFT01;
break;
case DST_IV:
tp = FFTW_RODFT11;
break;
default:
fprintf(stderr, "unknown type\n");
exit(EXIT_FAILURE);
}
switch(type) {
case DCT_I:
case DCT_II:
case DCT_III:
case DCT_IV:
for(i=0; i < sz; ++i) {
a[i] = i;
}
break;
case DST_I:
case DST_II:
case DST_III:
case DST_IV:
/* TODO: what should we do for dst's?*/
for(i=0; i < sz; ++i) {
a[i] = i;
}
break;
default:
fprintf(stderr, "unknown type\n");
exit(EXIT_FAILURE);
}
p = FFTW_PLAN_CREATE(sz, a, b, tp, FFTW_ESTIMATE);
FFTW_EXECUTE(p);
FFTW_DESTROY_PLAN(p);
for(i=0; i < sz; ++i) {
printf(PF"\n", b[i]);
}
FFTW_FREE(b);
FFTW_FREE(a);
return 0;
}
int main(int argc, char* argv[])
{
int n, tp;
if (argc < 3) {
fprintf(stderr, "missing argument: program type n\n");
exit(EXIT_FAILURE);
}
tp = atoi(argv[1]);
n = atoi(argv[2]);
gen(tp, n);
FFTW_CLEANUP();
return 0;
}

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from subprocess import Popen, PIPE, STDOUT
import numpy as np
SZ = [2, 3, 4, 8, 12, 15, 16, 17, 32, 64, 128, 256, 512, 1024]
def gen_data(dt):
arrays = {}
if dt == np.float128:
pg = './fftw_longdouble'
elif dt == np.double:
pg = './fftw_double'
elif dt == np.float32:
pg = './fftw_single'
else:
raise ValueError("unknown: %s" % dt)
# Generate test data using FFTW for reference
for type in [1, 2, 3, 4, 5, 6, 7, 8]:
arrays[type] = {}
for sz in SZ:
a = Popen([pg, str(type), str(sz)], stdout=PIPE, stderr=STDOUT)
st = [i.decode('ascii').strip() for i in a.stdout.readlines()]
arrays[type][sz] = np.fromstring(",".join(st), sep=',', dtype=dt)
return arrays
# generate single precision data
data = gen_data(np.float32)
filename = 'fftw_single_ref'
# Save ref data into npz format
d = {'sizes': SZ}
for type in [1, 2, 3, 4]:
for sz in SZ:
d['dct_%d_%d' % (type, sz)] = data[type][sz]
d['sizes'] = SZ
for type in [5, 6, 7, 8]:
for sz in SZ:
d['dst_%d_%d' % (type-4, sz)] = data[type][sz]
np.savez(filename, **d)
# generate double precision data
data = gen_data(np.float64)
filename = 'fftw_double_ref'
# Save ref data into npz format
d = {'sizes': SZ}
for type in [1, 2, 3, 4]:
for sz in SZ:
d['dct_%d_%d' % (type, sz)] = data[type][sz]
d['sizes'] = SZ
for type in [5, 6, 7, 8]:
for sz in SZ:
d['dst_%d_%d' % (type-4, sz)] = data[type][sz]
np.savez(filename, **d)
# generate long double precision data
data = gen_data(np.float128)
filename = 'fftw_longdouble_ref'
# Save ref data into npz format
d = {'sizes': SZ}
for type in [1, 2, 3, 4]:
for sz in SZ:
d['dct_%d_%d' % (type, sz)] = data[type][sz]
d['sizes'] = SZ
for type in [5, 6, 7, 8]:
for sz in SZ:
d['dst_%d_%d' % (type-4, sz)] = data[type][sz]
np.savez(filename, **d)

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x0 = linspace(0, 10, 11);
x1 = linspace(0, 10, 15);
x2 = linspace(0, 10, 16);
x3 = linspace(0, 10, 17);
x4 = randn(32, 1);
x5 = randn(64, 1);
x6 = randn(128, 1);
x7 = randn(256, 1);
y0 = dct(x0);
y1 = dct(x1);
y2 = dct(x2);
y3 = dct(x3);
y4 = dct(x4);
y5 = dct(x5);
y6 = dct(x6);
y7 = dct(x7);
save('test.mat', 'x0', 'x1', 'x2', 'x3', 'x4', 'x5', 'x6', 'x7', ...
'y0', 'y1', 'y2', 'y3', 'y4', 'y5', 'y6', 'y7');

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import numpy as np
from scipy.io import loadmat
m = loadmat('test.mat', squeeze_me=True, struct_as_record=True,
mat_dtype=True)
np.savez('test.npz', **m)

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# Created by Pearu Peterson, September 2002
from numpy.testing import (assert_, assert_equal, assert_array_almost_equal,
assert_array_almost_equal_nulp, assert_array_less)
import pytest
from pytest import raises as assert_raises
from scipy.fftpack import ifft, fft, fftn, ifftn, rfft, irfft, fft2
from numpy import (arange, add, array, asarray, zeros, dot, exp, pi,
swapaxes, double, cdouble)
import numpy as np
import numpy.fft
from numpy.random import rand
# "large" composite numbers supported by FFTPACK
LARGE_COMPOSITE_SIZES = [
2**13,
2**5 * 3**5,
2**3 * 3**3 * 5**2,
]
SMALL_COMPOSITE_SIZES = [
2,
2*3*5,
2*2*3*3,
]
# prime
LARGE_PRIME_SIZES = [
2011
]
SMALL_PRIME_SIZES = [
29
]
def _assert_close_in_norm(x, y, rtol, size, rdt):
# helper function for testing
err_msg = "size: %s rdt: %s" % (size, rdt)
assert_array_less(np.linalg.norm(x - y), rtol*np.linalg.norm(x), err_msg)
def random(size):
return rand(*size)
def get_mat(n):
data = arange(n)
data = add.outer(data, data)
return data
def direct_dft(x):
x = asarray(x)
n = len(x)
y = zeros(n, dtype=cdouble)
w = -arange(n)*(2j*pi/n)
for i in range(n):
y[i] = dot(exp(i*w), x)
return y
def direct_idft(x):
x = asarray(x)
n = len(x)
y = zeros(n, dtype=cdouble)
w = arange(n)*(2j*pi/n)
for i in range(n):
y[i] = dot(exp(i*w), x)/n
return y
def direct_dftn(x):
x = asarray(x)
for axis in range(len(x.shape)):
x = fft(x, axis=axis)
return x
def direct_idftn(x):
x = asarray(x)
for axis in range(len(x.shape)):
x = ifft(x, axis=axis)
return x
def direct_rdft(x):
x = asarray(x)
n = len(x)
w = -arange(n)*(2j*pi/n)
r = zeros(n, dtype=double)
for i in range(n//2+1):
y = dot(exp(i*w), x)
if i:
r[2*i-1] = y.real
if 2*i < n:
r[2*i] = y.imag
else:
r[0] = y.real
return r
def direct_irdft(x):
x = asarray(x)
n = len(x)
x1 = zeros(n, dtype=cdouble)
for i in range(n//2+1):
if i:
if 2*i < n:
x1[i] = x[2*i-1] + 1j*x[2*i]
x1[n-i] = x[2*i-1] - 1j*x[2*i]
else:
x1[i] = x[2*i-1]
else:
x1[0] = x[0]
return direct_idft(x1).real
class _TestFFTBase(object):
def setup_method(self):
self.cdt = None
self.rdt = None
np.random.seed(1234)
def test_definition(self):
x = np.array([1,2,3,4+1j,1,2,3,4+2j], dtype=self.cdt)
y = fft(x)
assert_equal(y.dtype, self.cdt)
y1 = direct_dft(x)
assert_array_almost_equal(y,y1)
x = np.array([1,2,3,4+0j,5], dtype=self.cdt)
assert_array_almost_equal(fft(x),direct_dft(x))
def test_n_argument_real(self):
x1 = np.array([1,2,3,4], dtype=self.rdt)
x2 = np.array([1,2,3,4], dtype=self.rdt)
y = fft([x1,x2],n=4)
assert_equal(y.dtype, self.cdt)
assert_equal(y.shape,(2,4))
assert_array_almost_equal(y[0],direct_dft(x1))
assert_array_almost_equal(y[1],direct_dft(x2))
def _test_n_argument_complex(self):
x1 = np.array([1,2,3,4+1j], dtype=self.cdt)
x2 = np.array([1,2,3,4+1j], dtype=self.cdt)
y = fft([x1,x2],n=4)
assert_equal(y.dtype, self.cdt)
assert_equal(y.shape,(2,4))
assert_array_almost_equal(y[0],direct_dft(x1))
assert_array_almost_equal(y[1],direct_dft(x2))
def test_invalid_sizes(self):
assert_raises(ValueError, fft, [])
assert_raises(ValueError, fft, [[1,1],[2,2]], -5)
class TestDoubleFFT(_TestFFTBase):
def setup_method(self):
self.cdt = np.cdouble
self.rdt = np.double
class TestSingleFFT(_TestFFTBase):
def setup_method(self):
self.cdt = np.complex64
self.rdt = np.float32
@pytest.mark.xfail(run=False, reason="single-precision FFT implementation is partially disabled, until accuracy issues with large prime powers are resolved")
def test_notice(self):
pass
class TestFloat16FFT(object):
def test_1_argument_real(self):
x1 = np.array([1, 2, 3, 4], dtype=np.float16)
y = fft(x1, n=4)
assert_equal(y.dtype, np.complex64)
assert_equal(y.shape, (4, ))
assert_array_almost_equal(y, direct_dft(x1.astype(np.float32)))
def test_n_argument_real(self):
x1 = np.array([1, 2, 3, 4], dtype=np.float16)
x2 = np.array([1, 2, 3, 4], dtype=np.float16)
y = fft([x1, x2], n=4)
assert_equal(y.dtype, np.complex64)
assert_equal(y.shape, (2, 4))
assert_array_almost_equal(y[0], direct_dft(x1.astype(np.float32)))
assert_array_almost_equal(y[1], direct_dft(x2.astype(np.float32)))
class _TestIFFTBase(object):
def setup_method(self):
np.random.seed(1234)
def test_definition(self):
x = np.array([1,2,3,4+1j,1,2,3,4+2j], self.cdt)
y = ifft(x)
y1 = direct_idft(x)
assert_equal(y.dtype, self.cdt)
assert_array_almost_equal(y,y1)
x = np.array([1,2,3,4+0j,5], self.cdt)
assert_array_almost_equal(ifft(x),direct_idft(x))
def test_definition_real(self):
x = np.array([1,2,3,4,1,2,3,4], self.rdt)
y = ifft(x)
assert_equal(y.dtype, self.cdt)
y1 = direct_idft(x)
assert_array_almost_equal(y,y1)
x = np.array([1,2,3,4,5], dtype=self.rdt)
assert_equal(y.dtype, self.cdt)
assert_array_almost_equal(ifft(x),direct_idft(x))
def test_random_complex(self):
for size in [1,51,111,100,200,64,128,256,1024]:
x = random([size]).astype(self.cdt)
x = random([size]).astype(self.cdt) + 1j*x
y1 = ifft(fft(x))
y2 = fft(ifft(x))
assert_equal(y1.dtype, self.cdt)
assert_equal(y2.dtype, self.cdt)
assert_array_almost_equal(y1, x)
assert_array_almost_equal(y2, x)
def test_random_real(self):
for size in [1,51,111,100,200,64,128,256,1024]:
x = random([size]).astype(self.rdt)
y1 = ifft(fft(x))
y2 = fft(ifft(x))
assert_equal(y1.dtype, self.cdt)
assert_equal(y2.dtype, self.cdt)
assert_array_almost_equal(y1, x)
assert_array_almost_equal(y2, x)
def test_size_accuracy(self):
# Sanity check for the accuracy for prime and non-prime sized inputs
if self.rdt == np.float32:
rtol = 1e-5
elif self.rdt == np.float64:
rtol = 1e-10
for size in LARGE_COMPOSITE_SIZES + LARGE_PRIME_SIZES:
np.random.seed(1234)
x = np.random.rand(size).astype(self.rdt)
y = ifft(fft(x))
_assert_close_in_norm(x, y, rtol, size, self.rdt)
y = fft(ifft(x))
_assert_close_in_norm(x, y, rtol, size, self.rdt)
x = (x + 1j*np.random.rand(size)).astype(self.cdt)
y = ifft(fft(x))
_assert_close_in_norm(x, y, rtol, size, self.rdt)
y = fft(ifft(x))
_assert_close_in_norm(x, y, rtol, size, self.rdt)
def test_invalid_sizes(self):
assert_raises(ValueError, ifft, [])
assert_raises(ValueError, ifft, [[1,1],[2,2]], -5)
class TestDoubleIFFT(_TestIFFTBase):
def setup_method(self):
self.cdt = np.cdouble
self.rdt = np.double
class TestSingleIFFT(_TestIFFTBase):
def setup_method(self):
self.cdt = np.complex64
self.rdt = np.float32
class _TestRFFTBase(object):
def setup_method(self):
np.random.seed(1234)
def test_definition(self):
for t in [[1, 2, 3, 4, 1, 2, 3, 4], [1, 2, 3, 4, 1, 2, 3, 4, 5]]:
x = np.array(t, dtype=self.rdt)
y = rfft(x)
y1 = direct_rdft(x)
assert_array_almost_equal(y,y1)
assert_equal(y.dtype, self.rdt)
def test_invalid_sizes(self):
assert_raises(ValueError, rfft, [])
assert_raises(ValueError, rfft, [[1,1],[2,2]], -5)
# See gh-5790
class MockSeries(object):
def __init__(self, data):
self.data = np.asarray(data)
def __getattr__(self, item):
try:
return getattr(self.data, item)
except AttributeError:
raise AttributeError(("'MockSeries' object "
"has no attribute '{attr}'".
format(attr=item)))
def test_non_ndarray_with_dtype(self):
x = np.array([1., 2., 3., 4., 5.])
xs = _TestRFFTBase.MockSeries(x)
expected = [1, 2, 3, 4, 5]
rfft(xs)
# Data should not have been overwritten
assert_equal(x, expected)
assert_equal(xs.data, expected)
def test_complex_input(self):
assert_raises(TypeError, rfft, np.arange(4, dtype=np.complex64))
class TestRFFTDouble(_TestRFFTBase):
def setup_method(self):
self.cdt = np.cdouble
self.rdt = np.double
class TestRFFTSingle(_TestRFFTBase):
def setup_method(self):
self.cdt = np.complex64
self.rdt = np.float32
class _TestIRFFTBase(object):
def setup_method(self):
np.random.seed(1234)
def test_definition(self):
x1 = [1,2,3,4,1,2,3,4]
x1_1 = [1,2+3j,4+1j,2+3j,4,2-3j,4-1j,2-3j]
x2 = [1,2,3,4,1,2,3,4,5]
x2_1 = [1,2+3j,4+1j,2+3j,4+5j,4-5j,2-3j,4-1j,2-3j]
def _test(x, xr):
y = irfft(np.array(x, dtype=self.rdt))
y1 = direct_irdft(x)
assert_equal(y.dtype, self.rdt)
assert_array_almost_equal(y,y1, decimal=self.ndec)
assert_array_almost_equal(y,ifft(xr), decimal=self.ndec)
_test(x1, x1_1)
_test(x2, x2_1)
def test_random_real(self):
for size in [1,51,111,100,200,64,128,256,1024]:
x = random([size]).astype(self.rdt)
y1 = irfft(rfft(x))
y2 = rfft(irfft(x))
assert_equal(y1.dtype, self.rdt)
assert_equal(y2.dtype, self.rdt)
assert_array_almost_equal(y1, x, decimal=self.ndec,
err_msg="size=%d" % size)
assert_array_almost_equal(y2, x, decimal=self.ndec,
err_msg="size=%d" % size)
def test_size_accuracy(self):
# Sanity check for the accuracy for prime and non-prime sized inputs
if self.rdt == np.float32:
rtol = 1e-5
elif self.rdt == np.float64:
rtol = 1e-10
for size in LARGE_COMPOSITE_SIZES + LARGE_PRIME_SIZES:
np.random.seed(1234)
x = np.random.rand(size).astype(self.rdt)
y = irfft(rfft(x))
_assert_close_in_norm(x, y, rtol, size, self.rdt)
y = rfft(irfft(x))
_assert_close_in_norm(x, y, rtol, size, self.rdt)
def test_invalid_sizes(self):
assert_raises(ValueError, irfft, [])
assert_raises(ValueError, irfft, [[1,1],[2,2]], -5)
def test_complex_input(self):
assert_raises(TypeError, irfft, np.arange(4, dtype=np.complex64))
# self.ndec is bogus; we should have a assert_array_approx_equal for number of
# significant digits
class TestIRFFTDouble(_TestIRFFTBase):
def setup_method(self):
self.cdt = np.cdouble
self.rdt = np.double
self.ndec = 14
class TestIRFFTSingle(_TestIRFFTBase):
def setup_method(self):
self.cdt = np.complex64
self.rdt = np.float32
self.ndec = 5
class Testfft2(object):
def setup_method(self):
np.random.seed(1234)
def test_regression_244(self):
"""FFT returns wrong result with axes parameter."""
# fftn (and hence fft2) used to break when both axes and shape were
# used
x = numpy.ones((4, 4, 2))
y = fft2(x, shape=(8, 8), axes=(-3, -2))
y_r = numpy.fft.fftn(x, s=(8, 8), axes=(-3, -2))
assert_array_almost_equal(y, y_r)
def test_invalid_sizes(self):
assert_raises(ValueError, fft2, [[]])
assert_raises(ValueError, fft2, [[1, 1], [2, 2]], (4, -3))
class TestFftnSingle(object):
def setup_method(self):
np.random.seed(1234)
def test_definition(self):
x = [[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]
y = fftn(np.array(x, np.float32))
assert_(y.dtype == np.complex64,
msg="double precision output with single precision")
y_r = np.array(fftn(x), np.complex64)
assert_array_almost_equal_nulp(y, y_r)
@pytest.mark.parametrize('size', SMALL_COMPOSITE_SIZES + SMALL_PRIME_SIZES)
def test_size_accuracy_small(self, size):
x = np.random.rand(size, size) + 1j*np.random.rand(size, size)
y1 = fftn(x.real.astype(np.float32))
y2 = fftn(x.real.astype(np.float64)).astype(np.complex64)
assert_equal(y1.dtype, np.complex64)
assert_array_almost_equal_nulp(y1, y2, 2000)
@pytest.mark.parametrize('size', LARGE_COMPOSITE_SIZES + LARGE_PRIME_SIZES)
def test_size_accuracy_large(self, size):
x = np.random.rand(size, 3) + 1j*np.random.rand(size, 3)
y1 = fftn(x.real.astype(np.float32))
y2 = fftn(x.real.astype(np.float64)).astype(np.complex64)
assert_equal(y1.dtype, np.complex64)
assert_array_almost_equal_nulp(y1, y2, 2000)
def test_definition_float16(self):
x = [[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]
y = fftn(np.array(x, np.float16))
assert_equal(y.dtype, np.complex64)
y_r = np.array(fftn(x), np.complex64)
assert_array_almost_equal_nulp(y, y_r)
@pytest.mark.parametrize('size', SMALL_COMPOSITE_SIZES + SMALL_PRIME_SIZES)
def test_float16_input_small(self, size):
x = np.random.rand(size, size) + 1j*np.random.rand(size, size)
y1 = fftn(x.real.astype(np.float16))
y2 = fftn(x.real.astype(np.float64)).astype(np.complex64)
assert_equal(y1.dtype, np.complex64)
assert_array_almost_equal_nulp(y1, y2, 5e5)
@pytest.mark.parametrize('size', LARGE_COMPOSITE_SIZES + LARGE_PRIME_SIZES)
def test_float16_input_large(self, size):
x = np.random.rand(size, 3) + 1j*np.random.rand(size, 3)
y1 = fftn(x.real.astype(np.float16))
y2 = fftn(x.real.astype(np.float64)).astype(np.complex64)
assert_equal(y1.dtype, np.complex64)
assert_array_almost_equal_nulp(y1, y2, 2e6)
class TestFftn(object):
def setup_method(self):
np.random.seed(1234)
def test_definition(self):
x = [[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]
y = fftn(x)
assert_array_almost_equal(y, direct_dftn(x))
x = random((20, 26))
assert_array_almost_equal(fftn(x), direct_dftn(x))
x = random((5, 4, 3, 20))
assert_array_almost_equal(fftn(x), direct_dftn(x))
def test_axes_argument(self):
# plane == ji_plane, x== kji_space
plane1 = [[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]
plane2 = [[10, 11, 12],
[13, 14, 15],
[16, 17, 18]]
plane3 = [[19, 20, 21],
[22, 23, 24],
[25, 26, 27]]
ki_plane1 = [[1, 2, 3],
[10, 11, 12],
[19, 20, 21]]
ki_plane2 = [[4, 5, 6],
[13, 14, 15],
[22, 23, 24]]
ki_plane3 = [[7, 8, 9],
[16, 17, 18],
[25, 26, 27]]
jk_plane1 = [[1, 10, 19],
[4, 13, 22],
[7, 16, 25]]
jk_plane2 = [[2, 11, 20],
[5, 14, 23],
[8, 17, 26]]
jk_plane3 = [[3, 12, 21],
[6, 15, 24],
[9, 18, 27]]
kj_plane1 = [[1, 4, 7],
[10, 13, 16], [19, 22, 25]]
kj_plane2 = [[2, 5, 8],
[11, 14, 17], [20, 23, 26]]
kj_plane3 = [[3, 6, 9],
[12, 15, 18], [21, 24, 27]]
ij_plane1 = [[1, 4, 7],
[2, 5, 8],
[3, 6, 9]]
ij_plane2 = [[10, 13, 16],
[11, 14, 17],
[12, 15, 18]]
ij_plane3 = [[19, 22, 25],
[20, 23, 26],
[21, 24, 27]]
ik_plane1 = [[1, 10, 19],
[2, 11, 20],
[3, 12, 21]]
ik_plane2 = [[4, 13, 22],
[5, 14, 23],
[6, 15, 24]]
ik_plane3 = [[7, 16, 25],
[8, 17, 26],
[9, 18, 27]]
ijk_space = [jk_plane1, jk_plane2, jk_plane3]
ikj_space = [kj_plane1, kj_plane2, kj_plane3]
jik_space = [ik_plane1, ik_plane2, ik_plane3]
jki_space = [ki_plane1, ki_plane2, ki_plane3]
kij_space = [ij_plane1, ij_plane2, ij_plane3]
x = array([plane1, plane2, plane3])
assert_array_almost_equal(fftn(x),
fftn(x, axes=(-3, -2, -1))) # kji_space
assert_array_almost_equal(fftn(x), fftn(x, axes=(0, 1, 2)))
assert_array_almost_equal(fftn(x, axes=(0, 2)), fftn(x, axes=(0, -1)))
y = fftn(x, axes=(2, 1, 0)) # ijk_space
assert_array_almost_equal(swapaxes(y, -1, -3), fftn(ijk_space))
y = fftn(x, axes=(2, 0, 1)) # ikj_space
assert_array_almost_equal(swapaxes(swapaxes(y, -1, -3), -1, -2),
fftn(ikj_space))
y = fftn(x, axes=(1, 2, 0)) # jik_space
assert_array_almost_equal(swapaxes(swapaxes(y, -1, -3), -3, -2),
fftn(jik_space))
y = fftn(x, axes=(1, 0, 2)) # jki_space
assert_array_almost_equal(swapaxes(y, -2, -3), fftn(jki_space))
y = fftn(x, axes=(0, 2, 1)) # kij_space
assert_array_almost_equal(swapaxes(y, -2, -1), fftn(kij_space))
y = fftn(x, axes=(-2, -1)) # ji_plane
assert_array_almost_equal(fftn(plane1), y[0])
assert_array_almost_equal(fftn(plane2), y[1])
assert_array_almost_equal(fftn(plane3), y[2])
y = fftn(x, axes=(1, 2)) # ji_plane
assert_array_almost_equal(fftn(plane1), y[0])
assert_array_almost_equal(fftn(plane2), y[1])
assert_array_almost_equal(fftn(plane3), y[2])
y = fftn(x, axes=(-3, -2)) # kj_plane
assert_array_almost_equal(fftn(x[:, :, 0]), y[:, :, 0])
assert_array_almost_equal(fftn(x[:, :, 1]), y[:, :, 1])
assert_array_almost_equal(fftn(x[:, :, 2]), y[:, :, 2])
y = fftn(x, axes=(-3, -1)) # ki_plane
assert_array_almost_equal(fftn(x[:, 0, :]), y[:, 0, :])
assert_array_almost_equal(fftn(x[:, 1, :]), y[:, 1, :])
assert_array_almost_equal(fftn(x[:, 2, :]), y[:, 2, :])
y = fftn(x, axes=(-1, -2)) # ij_plane
assert_array_almost_equal(fftn(ij_plane1), swapaxes(y[0], -2, -1))
assert_array_almost_equal(fftn(ij_plane2), swapaxes(y[1], -2, -1))
assert_array_almost_equal(fftn(ij_plane3), swapaxes(y[2], -2, -1))
y = fftn(x, axes=(-1, -3)) # ik_plane
assert_array_almost_equal(fftn(ik_plane1),
swapaxes(y[:, 0, :], -1, -2))
assert_array_almost_equal(fftn(ik_plane2),
swapaxes(y[:, 1, :], -1, -2))
assert_array_almost_equal(fftn(ik_plane3),
swapaxes(y[:, 2, :], -1, -2))
y = fftn(x, axes=(-2, -3)) # jk_plane
assert_array_almost_equal(fftn(jk_plane1),
swapaxes(y[:, :, 0], -1, -2))
assert_array_almost_equal(fftn(jk_plane2),
swapaxes(y[:, :, 1], -1, -2))
assert_array_almost_equal(fftn(jk_plane3),
swapaxes(y[:, :, 2], -1, -2))
y = fftn(x, axes=(-1,)) # i_line
for i in range(3):
for j in range(3):
assert_array_almost_equal(fft(x[i, j, :]), y[i, j, :])
y = fftn(x, axes=(-2,)) # j_line
for i in range(3):
for j in range(3):
assert_array_almost_equal(fft(x[i, :, j]), y[i, :, j])
y = fftn(x, axes=(0,)) # k_line
for i in range(3):
for j in range(3):
assert_array_almost_equal(fft(x[:, i, j]), y[:, i, j])
y = fftn(x, axes=()) # point
assert_array_almost_equal(y, x)
def test_shape_argument(self):
small_x = [[1, 2, 3],
[4, 5, 6]]
large_x1 = [[1, 2, 3, 0],
[4, 5, 6, 0],
[0, 0, 0, 0],
[0, 0, 0, 0]]
y = fftn(small_x, shape=(4, 4))
assert_array_almost_equal(y, fftn(large_x1))
y = fftn(small_x, shape=(3, 4))
assert_array_almost_equal(y, fftn(large_x1[:-1]))
def test_shape_axes_argument(self):
small_x = [[1, 2, 3],
[4, 5, 6],
[7, 8, 9]]
large_x1 = array([[1, 2, 3, 0],
[4, 5, 6, 0],
[7, 8, 9, 0],
[0, 0, 0, 0]])
y = fftn(small_x, shape=(4, 4), axes=(-2, -1))
assert_array_almost_equal(y, fftn(large_x1))
y = fftn(small_x, shape=(4, 4), axes=(-1, -2))
assert_array_almost_equal(y, swapaxes(
fftn(swapaxes(large_x1, -1, -2)), -1, -2))
def test_shape_axes_argument2(self):
# Change shape of the last axis
x = numpy.random.random((10, 5, 3, 7))
y = fftn(x, axes=(-1,), shape=(8,))
assert_array_almost_equal(y, fft(x, axis=-1, n=8))
# Change shape of an arbitrary axis which is not the last one
x = numpy.random.random((10, 5, 3, 7))
y = fftn(x, axes=(-2,), shape=(8,))
assert_array_almost_equal(y, fft(x, axis=-2, n=8))
# Change shape of axes: cf #244, where shape and axes were mixed up
x = numpy.random.random((4, 4, 2))
y = fftn(x, axes=(-3, -2), shape=(8, 8))
assert_array_almost_equal(y,
numpy.fft.fftn(x, axes=(-3, -2), s=(8, 8)))
def test_shape_argument_more(self):
x = zeros((4, 4, 2))
with assert_raises(ValueError,
match="when given, axes and shape arguments"
" have to be of the same length"):
fftn(x, shape=(8, 8, 2, 1))
def test_invalid_sizes(self):
with assert_raises(ValueError,
match="invalid number of data points"
r" \(\[1, 0\]\) specified"):
fftn([[]])
with assert_raises(ValueError,
match="invalid number of data points"
r" \(\[4, -3\]\) specified"):
fftn([[1, 1], [2, 2]], (4, -3))
class TestIfftn(object):
dtype = None
cdtype = None
def setup_method(self):
np.random.seed(1234)
@pytest.mark.parametrize('dtype,cdtype,maxnlp',
[(np.float64, np.complex128, 2000),
(np.float32, np.complex64, 3500)])
def test_definition(self, dtype, cdtype, maxnlp):
x = np.array([[1, 2, 3],
[4, 5, 6],
[7, 8, 9]], dtype=dtype)
y = ifftn(x)
assert_equal(y.dtype, cdtype)
assert_array_almost_equal_nulp(y, direct_idftn(x), maxnlp)
x = random((20, 26))
assert_array_almost_equal_nulp(ifftn(x), direct_idftn(x), maxnlp)
x = random((5, 4, 3, 20))
assert_array_almost_equal_nulp(ifftn(x), direct_idftn(x), maxnlp)
@pytest.mark.parametrize('maxnlp', [2000, 3500])
@pytest.mark.parametrize('size', [1, 2, 51, 32, 64, 92])
def test_random_complex(self, maxnlp, size):
x = random([size, size]) + 1j*random([size, size])
assert_array_almost_equal_nulp(ifftn(fftn(x)), x, maxnlp)
assert_array_almost_equal_nulp(fftn(ifftn(x)), x, maxnlp)
def test_invalid_sizes(self):
with assert_raises(ValueError,
match="invalid number of data points"
r" \(\[1, 0\]\) specified"):
ifftn([[]])
with assert_raises(ValueError,
match="invalid number of data points"
r" \(\[4, -3\]\) specified"):
ifftn([[1, 1], [2, 2]], (4, -3))
class FakeArray(object):
def __init__(self, data):
self._data = data
self.__array_interface__ = data.__array_interface__
class FakeArray2(object):
def __init__(self, data):
self._data = data
def __array__(self):
return self._data
class TestOverwrite(object):
"""Check input overwrite behavior of the FFT functions."""
real_dtypes = (np.float32, np.float64)
dtypes = real_dtypes + (np.complex64, np.complex128)
fftsizes = [8, 16, 32]
def _check(self, x, routine, fftsize, axis, overwrite_x):
x2 = x.copy()
for fake in [lambda x: x, FakeArray, FakeArray2]:
routine(fake(x2), fftsize, axis, overwrite_x=overwrite_x)
sig = "%s(%s%r, %r, axis=%r, overwrite_x=%r)" % (
routine.__name__, x.dtype, x.shape, fftsize, axis, overwrite_x)
if not overwrite_x:
assert_equal(x2, x, err_msg="spurious overwrite in %s" % sig)
def _check_1d(self, routine, dtype, shape, axis, overwritable_dtypes,
fftsize, overwrite_x):
np.random.seed(1234)
if np.issubdtype(dtype, np.complexfloating):
data = np.random.randn(*shape) + 1j*np.random.randn(*shape)
else:
data = np.random.randn(*shape)
data = data.astype(dtype)
self._check(data, routine, fftsize, axis,
overwrite_x=overwrite_x)
@pytest.mark.parametrize('dtype', dtypes)
@pytest.mark.parametrize('fftsize', fftsizes)
@pytest.mark.parametrize('overwrite_x', [True, False])
@pytest.mark.parametrize('shape,axes', [((16,), -1),
((16, 2), 0),
((2, 16), 1)])
def test_fft_ifft(self, dtype, fftsize, overwrite_x, shape, axes):
overwritable = (np.complex128, np.complex64)
self._check_1d(fft, dtype, shape, axes, overwritable,
fftsize, overwrite_x)
self._check_1d(ifft, dtype, shape, axes, overwritable,
fftsize, overwrite_x)
@pytest.mark.parametrize('dtype', real_dtypes)
@pytest.mark.parametrize('fftsize', fftsizes)
@pytest.mark.parametrize('overwrite_x', [True, False])
@pytest.mark.parametrize('shape,axes', [((16,), -1),
((16, 2), 0),
((2, 16), 1)])
def test_rfft_irfft(self, dtype, fftsize, overwrite_x, shape, axes):
overwritable = self.real_dtypes
self._check_1d(irfft, dtype, shape, axes, overwritable,
fftsize, overwrite_x)
self._check_1d(rfft, dtype, shape, axes, overwritable,
fftsize, overwrite_x)
def _check_nd_one(self, routine, dtype, shape, axes, overwritable_dtypes,
overwrite_x):
np.random.seed(1234)
if np.issubdtype(dtype, np.complexfloating):
data = np.random.randn(*shape) + 1j*np.random.randn(*shape)
else:
data = np.random.randn(*shape)
data = data.astype(dtype)
def fftshape_iter(shp):
if len(shp) <= 0:
yield ()
else:
for j in (shp[0]//2, shp[0], shp[0]*2):
for rest in fftshape_iter(shp[1:]):
yield (j,) + rest
if axes is None:
part_shape = shape
else:
part_shape = tuple(np.take(shape, axes))
for fftshape in fftshape_iter(part_shape):
self._check(data, routine, fftshape, axes,
overwrite_x=overwrite_x)
if data.ndim > 1:
self._check(data.T, routine, fftshape, axes,
overwrite_x=overwrite_x)
@pytest.mark.parametrize('dtype', dtypes)
@pytest.mark.parametrize('overwrite_x', [True, False])
@pytest.mark.parametrize('shape,axes', [((16,), None),
((16,), (0,)),
((16, 2), (0,)),
((2, 16), (1,)),
((8, 16), None),
((8, 16), (0, 1)),
((8, 16, 2), (0, 1)),
((8, 16, 2), (1, 2)),
((8, 16, 2), (0,)),
((8, 16, 2), (1,)),
((8, 16, 2), (2,)),
((8, 16, 2), None),
((8, 16, 2), (0, 1, 2))])
def test_fftn_ifftn(self, dtype, overwrite_x, shape, axes):
overwritable = (np.complex128, np.complex64)
self._check_nd_one(fftn, dtype, shape, axes, overwritable,
overwrite_x)
self._check_nd_one(ifftn, dtype, shape, axes, overwritable,
overwrite_x)

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@ -0,0 +1,54 @@
# Created by Pearu Peterson, September 2002
__usage__ = """
Build fftpack:
python setup_fftpack.py build
Run tests if scipy is installed:
python -c 'import scipy;scipy.fftpack.test(<level>)'
Run tests if fftpack is not installed:
python tests/test_helper.py [<level>]
"""
from numpy.testing import assert_array_almost_equal
from scipy.fftpack import fftshift, ifftshift, fftfreq, rfftfreq
from numpy import pi, random
class TestFFTShift(object):
def test_definition(self):
x = [0,1,2,3,4,-4,-3,-2,-1]
y = [-4,-3,-2,-1,0,1,2,3,4]
assert_array_almost_equal(fftshift(x),y)
assert_array_almost_equal(ifftshift(y),x)
x = [0,1,2,3,4,-5,-4,-3,-2,-1]
y = [-5,-4,-3,-2,-1,0,1,2,3,4]
assert_array_almost_equal(fftshift(x),y)
assert_array_almost_equal(ifftshift(y),x)
def test_inverse(self):
for n in [1,4,9,100,211]:
x = random.random((n,))
assert_array_almost_equal(ifftshift(fftshift(x)),x)
class TestFFTFreq(object):
def test_definition(self):
x = [0,1,2,3,4,-4,-3,-2,-1]
assert_array_almost_equal(9*fftfreq(9),x)
assert_array_almost_equal(9*pi*fftfreq(9,pi),x)
x = [0,1,2,3,4,-5,-4,-3,-2,-1]
assert_array_almost_equal(10*fftfreq(10),x)
assert_array_almost_equal(10*pi*fftfreq(10,pi),x)
class TestRFFTFreq(object):
def test_definition(self):
x = [0,1,1,2,2,3,3,4,4]
assert_array_almost_equal(9*rfftfreq(9),x)
assert_array_almost_equal(9*pi*rfftfreq(9,pi),x)
x = [0,1,1,2,2,3,3,4,4,5]
assert_array_almost_equal(10*rfftfreq(10),x)
assert_array_almost_equal(10*pi*rfftfreq(10,pi),x)

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"""Test possibility of patching fftpack with pyfftw.
No module source outside of scipy.fftpack should contain an import of
the form `from scipy.fftpack import ...`, so that a simple replacement
of scipy.fftpack by the corresponding fftw interface completely swaps
the two FFT implementations.
Because this simply inspects source files, we only need to run the test
on one version of Python.
"""
from pathlib import Path
import re
import tokenize
from numpy.testing import assert_
import scipy
class TestFFTPackImport(object):
def test_fftpack_import(self):
base = Path(scipy.__file__).parent
regexp = r"\s*from.+\.fftpack import .*\n"
for path in base.rglob("*.py"):
if base / "fftpack" in path.parents:
continue
# use tokenize to auto-detect encoding on systems where no
# default encoding is defined (e.g., LANG='C')
with tokenize.open(str(path)) as file:
assert_(all(not re.fullmatch(regexp, line)
for line in file),
"{0} contains an import from fftpack".format(path))

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# Created by Pearu Peterson, September 2002
__usage__ = """
Build fftpack:
python setup_fftpack.py build
Run tests if scipy is installed:
python -c 'import scipy;scipy.fftpack.test(<level>)'
Run tests if fftpack is not installed:
python tests/test_pseudo_diffs.py [<level>]
"""
from numpy.testing import (assert_equal, assert_almost_equal,
assert_array_almost_equal)
from scipy.fftpack import (diff, fft, ifft, tilbert, itilbert, hilbert,
ihilbert, shift, fftfreq, cs_diff, sc_diff,
ss_diff, cc_diff)
import numpy as np
from numpy import arange, sin, cos, pi, exp, tanh, sum, sign
from numpy.random import random
def direct_diff(x,k=1,period=None):
fx = fft(x)
n = len(fx)
if period is None:
period = 2*pi
w = fftfreq(n)*2j*pi/period*n
if k < 0:
w = 1 / w**k
w[0] = 0.0
else:
w = w**k
if n > 2000:
w[250:n-250] = 0.0
return ifft(w*fx).real
def direct_tilbert(x,h=1,period=None):
fx = fft(x)
n = len(fx)
if period is None:
period = 2*pi
w = fftfreq(n)*h*2*pi/period*n
w[0] = 1
w = 1j/tanh(w)
w[0] = 0j
return ifft(w*fx)
def direct_itilbert(x,h=1,period=None):
fx = fft(x)
n = len(fx)
if period is None:
period = 2*pi
w = fftfreq(n)*h*2*pi/period*n
w = -1j*tanh(w)
return ifft(w*fx)
def direct_hilbert(x):
fx = fft(x)
n = len(fx)
w = fftfreq(n)*n
w = 1j*sign(w)
return ifft(w*fx)
def direct_ihilbert(x):
return -direct_hilbert(x)
def direct_shift(x,a,period=None):
n = len(x)
if period is None:
k = fftfreq(n)*1j*n
else:
k = fftfreq(n)*2j*pi/period*n
return ifft(fft(x)*exp(k*a)).real
class TestDiff(object):
def test_definition(self):
for n in [16,17,64,127,32]:
x = arange(n)*2*pi/n
assert_array_almost_equal(diff(sin(x)),direct_diff(sin(x)))
assert_array_almost_equal(diff(sin(x),2),direct_diff(sin(x),2))
assert_array_almost_equal(diff(sin(x),3),direct_diff(sin(x),3))
assert_array_almost_equal(diff(sin(x),4),direct_diff(sin(x),4))
assert_array_almost_equal(diff(sin(x),5),direct_diff(sin(x),5))
assert_array_almost_equal(diff(sin(2*x),3),direct_diff(sin(2*x),3))
assert_array_almost_equal(diff(sin(2*x),4),direct_diff(sin(2*x),4))
assert_array_almost_equal(diff(cos(x)),direct_diff(cos(x)))
assert_array_almost_equal(diff(cos(x),2),direct_diff(cos(x),2))
assert_array_almost_equal(diff(cos(x),3),direct_diff(cos(x),3))
assert_array_almost_equal(diff(cos(x),4),direct_diff(cos(x),4))
assert_array_almost_equal(diff(cos(2*x)),direct_diff(cos(2*x)))
assert_array_almost_equal(diff(sin(x*n/8)),direct_diff(sin(x*n/8)))
assert_array_almost_equal(diff(cos(x*n/8)),direct_diff(cos(x*n/8)))
for k in range(5):
assert_array_almost_equal(diff(sin(4*x),k),direct_diff(sin(4*x),k))
assert_array_almost_equal(diff(cos(4*x),k),direct_diff(cos(4*x),k))
def test_period(self):
for n in [17,64]:
x = arange(n)/float(n)
assert_array_almost_equal(diff(sin(2*pi*x),period=1),
2*pi*cos(2*pi*x))
assert_array_almost_equal(diff(sin(2*pi*x),3,period=1),
-(2*pi)**3*cos(2*pi*x))
def test_sin(self):
for n in [32,64,77]:
x = arange(n)*2*pi/n
assert_array_almost_equal(diff(sin(x)),cos(x))
assert_array_almost_equal(diff(cos(x)),-sin(x))
assert_array_almost_equal(diff(sin(x),2),-sin(x))
assert_array_almost_equal(diff(sin(x),4),sin(x))
assert_array_almost_equal(diff(sin(4*x)),4*cos(4*x))
assert_array_almost_equal(diff(sin(sin(x))),cos(x)*cos(sin(x)))
def test_expr(self):
for n in [64,77,100,128,256,512,1024,2048,4096,8192][:5]:
x = arange(n)*2*pi/n
f = sin(x)*cos(4*x)+exp(sin(3*x))
df = cos(x)*cos(4*x)-4*sin(x)*sin(4*x)+3*cos(3*x)*exp(sin(3*x))
ddf = -17*sin(x)*cos(4*x)-8*cos(x)*sin(4*x)\
- 9*sin(3*x)*exp(sin(3*x))+9*cos(3*x)**2*exp(sin(3*x))
d1 = diff(f)
assert_array_almost_equal(d1,df)
assert_array_almost_equal(diff(df),ddf)
assert_array_almost_equal(diff(f,2),ddf)
assert_array_almost_equal(diff(ddf,-1),df)
def test_expr_large(self):
for n in [2048,4096]:
x = arange(n)*2*pi/n
f = sin(x)*cos(4*x)+exp(sin(3*x))
df = cos(x)*cos(4*x)-4*sin(x)*sin(4*x)+3*cos(3*x)*exp(sin(3*x))
ddf = -17*sin(x)*cos(4*x)-8*cos(x)*sin(4*x)\
- 9*sin(3*x)*exp(sin(3*x))+9*cos(3*x)**2*exp(sin(3*x))
assert_array_almost_equal(diff(f),df)
assert_array_almost_equal(diff(df),ddf)
assert_array_almost_equal(diff(ddf,-1),df)
assert_array_almost_equal(diff(f,2),ddf)
def test_int(self):
n = 64
x = arange(n)*2*pi/n
assert_array_almost_equal(diff(sin(x),-1),-cos(x))
assert_array_almost_equal(diff(sin(x),-2),-sin(x))
assert_array_almost_equal(diff(sin(x),-4),sin(x))
assert_array_almost_equal(diff(2*cos(2*x),-1),sin(2*x))
def test_random_even(self):
for k in [0,2,4,6]:
for n in [60,32,64,56,55]:
f = random((n,))
af = sum(f,axis=0)/n
f = f-af
# zeroing Nyquist mode:
f = diff(diff(f,1),-1)
assert_almost_equal(sum(f,axis=0),0.0)
assert_array_almost_equal(diff(diff(f,k),-k),f)
assert_array_almost_equal(diff(diff(f,-k),k),f)
def test_random_odd(self):
for k in [0,1,2,3,4,5,6]:
for n in [33,65,55]:
f = random((n,))
af = sum(f,axis=0)/n
f = f-af
assert_almost_equal(sum(f,axis=0),0.0)
assert_array_almost_equal(diff(diff(f,k),-k),f)
assert_array_almost_equal(diff(diff(f,-k),k),f)
def test_zero_nyquist(self):
for k in [0,1,2,3,4,5,6]:
for n in [32,33,64,56,55]:
f = random((n,))
af = sum(f,axis=0)/n
f = f-af
# zeroing Nyquist mode:
f = diff(diff(f,1),-1)
assert_almost_equal(sum(f,axis=0),0.0)
assert_array_almost_equal(diff(diff(f,k),-k),f)
assert_array_almost_equal(diff(diff(f,-k),k),f)
class TestTilbert(object):
def test_definition(self):
for h in [0.1,0.5,1,5.5,10]:
for n in [16,17,64,127]:
x = arange(n)*2*pi/n
y = tilbert(sin(x),h)
y1 = direct_tilbert(sin(x),h)
assert_array_almost_equal(y,y1)
assert_array_almost_equal(tilbert(sin(x),h),
direct_tilbert(sin(x),h))
assert_array_almost_equal(tilbert(sin(2*x),h),
direct_tilbert(sin(2*x),h))
def test_random_even(self):
for h in [0.1,0.5,1,5.5,10]:
for n in [32,64,56]:
f = random((n,))
af = sum(f,axis=0)/n
f = f-af
assert_almost_equal(sum(f,axis=0),0.0)
assert_array_almost_equal(direct_tilbert(direct_itilbert(f,h),h),f)
def test_random_odd(self):
for h in [0.1,0.5,1,5.5,10]:
for n in [33,65,55]:
f = random((n,))
af = sum(f,axis=0)/n
f = f-af
assert_almost_equal(sum(f,axis=0),0.0)
assert_array_almost_equal(itilbert(tilbert(f,h),h),f)
assert_array_almost_equal(tilbert(itilbert(f,h),h),f)
class TestITilbert(object):
def test_definition(self):
for h in [0.1,0.5,1,5.5,10]:
for n in [16,17,64,127]:
x = arange(n)*2*pi/n
y = itilbert(sin(x),h)
y1 = direct_itilbert(sin(x),h)
assert_array_almost_equal(y,y1)
assert_array_almost_equal(itilbert(sin(x),h),
direct_itilbert(sin(x),h))
assert_array_almost_equal(itilbert(sin(2*x),h),
direct_itilbert(sin(2*x),h))
class TestHilbert(object):
def test_definition(self):
for n in [16,17,64,127]:
x = arange(n)*2*pi/n
y = hilbert(sin(x))
y1 = direct_hilbert(sin(x))
assert_array_almost_equal(y,y1)
assert_array_almost_equal(hilbert(sin(2*x)),
direct_hilbert(sin(2*x)))
def test_tilbert_relation(self):
for n in [16,17,64,127]:
x = arange(n)*2*pi/n
f = sin(x)+cos(2*x)*sin(x)
y = hilbert(f)
y1 = direct_hilbert(f)
assert_array_almost_equal(y,y1)
y2 = tilbert(f,h=10)
assert_array_almost_equal(y,y2)
def test_random_odd(self):
for n in [33,65,55]:
f = random((n,))
af = sum(f,axis=0)/n
f = f-af
assert_almost_equal(sum(f,axis=0),0.0)
assert_array_almost_equal(ihilbert(hilbert(f)),f)
assert_array_almost_equal(hilbert(ihilbert(f)),f)
def test_random_even(self):
for n in [32,64,56]:
f = random((n,))
af = sum(f,axis=0)/n
f = f-af
# zeroing Nyquist mode:
f = diff(diff(f,1),-1)
assert_almost_equal(sum(f,axis=0),0.0)
assert_array_almost_equal(direct_hilbert(direct_ihilbert(f)),f)
assert_array_almost_equal(hilbert(ihilbert(f)),f)
class TestIHilbert(object):
def test_definition(self):
for n in [16,17,64,127]:
x = arange(n)*2*pi/n
y = ihilbert(sin(x))
y1 = direct_ihilbert(sin(x))
assert_array_almost_equal(y,y1)
assert_array_almost_equal(ihilbert(sin(2*x)),
direct_ihilbert(sin(2*x)))
def test_itilbert_relation(self):
for n in [16,17,64,127]:
x = arange(n)*2*pi/n
f = sin(x)+cos(2*x)*sin(x)
y = ihilbert(f)
y1 = direct_ihilbert(f)
assert_array_almost_equal(y,y1)
y2 = itilbert(f,h=10)
assert_array_almost_equal(y,y2)
class TestShift(object):
def test_definition(self):
for n in [18,17,64,127,32,2048,256]:
x = arange(n)*2*pi/n
for a in [0.1,3]:
assert_array_almost_equal(shift(sin(x),a),direct_shift(sin(x),a))
assert_array_almost_equal(shift(sin(x),a),sin(x+a))
assert_array_almost_equal(shift(cos(x),a),cos(x+a))
assert_array_almost_equal(shift(cos(2*x)+sin(x),a),
cos(2*(x+a))+sin(x+a))
assert_array_almost_equal(shift(exp(sin(x)),a),exp(sin(x+a)))
assert_array_almost_equal(shift(sin(x),2*pi),sin(x))
assert_array_almost_equal(shift(sin(x),pi),-sin(x))
assert_array_almost_equal(shift(sin(x),pi/2),cos(x))
class TestOverwrite(object):
"""Check input overwrite behavior """
real_dtypes = (np.float32, np.float64)
dtypes = real_dtypes + (np.complex64, np.complex128)
def _check(self, x, routine, *args, **kwargs):
x2 = x.copy()
routine(x2, *args, **kwargs)
sig = routine.__name__
if args:
sig += repr(args)
if kwargs:
sig += repr(kwargs)
assert_equal(x2, x, err_msg="spurious overwrite in %s" % sig)
def _check_1d(self, routine, dtype, shape, *args, **kwargs):
np.random.seed(1234)
if np.issubdtype(dtype, np.complexfloating):
data = np.random.randn(*shape) + 1j*np.random.randn(*shape)
else:
data = np.random.randn(*shape)
data = data.astype(dtype)
self._check(data, routine, *args, **kwargs)
def test_diff(self):
for dtype in self.dtypes:
self._check_1d(diff, dtype, (16,))
def test_tilbert(self):
for dtype in self.dtypes:
self._check_1d(tilbert, dtype, (16,), 1.6)
def test_itilbert(self):
for dtype in self.dtypes:
self._check_1d(itilbert, dtype, (16,), 1.6)
def test_hilbert(self):
for dtype in self.dtypes:
self._check_1d(hilbert, dtype, (16,))
def test_cs_diff(self):
for dtype in self.dtypes:
self._check_1d(cs_diff, dtype, (16,), 1.0, 4.0)
def test_sc_diff(self):
for dtype in self.dtypes:
self._check_1d(sc_diff, dtype, (16,), 1.0, 4.0)
def test_ss_diff(self):
for dtype in self.dtypes:
self._check_1d(ss_diff, dtype, (16,), 1.0, 4.0)
def test_cc_diff(self):
for dtype in self.dtypes:
self._check_1d(cc_diff, dtype, (16,), 1.0, 4.0)
def test_shift(self):
for dtype in self.dtypes:
self._check_1d(shift, dtype, (16,), 1.0)

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from os.path import join, dirname
import numpy as np
from numpy.testing import assert_array_almost_equal, assert_equal
import pytest
from pytest import raises as assert_raises
from scipy.fftpack.realtransforms import (
dct, idct, dst, idst, dctn, idctn, dstn, idstn)
# Matlab reference data
MDATA = np.load(join(dirname(__file__), 'test.npz'))
X = [MDATA['x%d' % i] for i in range(8)]
Y = [MDATA['y%d' % i] for i in range(8)]
# FFTW reference data: the data are organized as follows:
# * SIZES is an array containing all available sizes
# * for every type (1, 2, 3, 4) and every size, the array dct_type_size
# contains the output of the DCT applied to the input np.linspace(0, size-1,
# size)
FFTWDATA_DOUBLE = np.load(join(dirname(__file__), 'fftw_double_ref.npz'))
FFTWDATA_SINGLE = np.load(join(dirname(__file__), 'fftw_single_ref.npz'))
FFTWDATA_SIZES = FFTWDATA_DOUBLE['sizes']
def fftw_dct_ref(type, size, dt):
x = np.linspace(0, size-1, size).astype(dt)
dt = np.result_type(np.float32, dt)
if dt == np.double:
data = FFTWDATA_DOUBLE
elif dt == np.float32:
data = FFTWDATA_SINGLE
else:
raise ValueError()
y = (data['dct_%d_%d' % (type, size)]).astype(dt)
return x, y, dt
def fftw_dst_ref(type, size, dt):
x = np.linspace(0, size-1, size).astype(dt)
dt = np.result_type(np.float32, dt)
if dt == np.double:
data = FFTWDATA_DOUBLE
elif dt == np.float32:
data = FFTWDATA_SINGLE
else:
raise ValueError()
y = (data['dst_%d_%d' % (type, size)]).astype(dt)
return x, y, dt
def dct_2d_ref(x, **kwargs):
"""Calculate reference values for testing dct2."""
x = np.array(x, copy=True)
for row in range(x.shape[0]):
x[row, :] = dct(x[row, :], **kwargs)
for col in range(x.shape[1]):
x[:, col] = dct(x[:, col], **kwargs)
return x
def idct_2d_ref(x, **kwargs):
"""Calculate reference values for testing idct2."""
x = np.array(x, copy=True)
for row in range(x.shape[0]):
x[row, :] = idct(x[row, :], **kwargs)
for col in range(x.shape[1]):
x[:, col] = idct(x[:, col], **kwargs)
return x
def dst_2d_ref(x, **kwargs):
"""Calculate reference values for testing dst2."""
x = np.array(x, copy=True)
for row in range(x.shape[0]):
x[row, :] = dst(x[row, :], **kwargs)
for col in range(x.shape[1]):
x[:, col] = dst(x[:, col], **kwargs)
return x
def idst_2d_ref(x, **kwargs):
"""Calculate reference values for testing idst2."""
x = np.array(x, copy=True)
for row in range(x.shape[0]):
x[row, :] = idst(x[row, :], **kwargs)
for col in range(x.shape[1]):
x[:, col] = idst(x[:, col], **kwargs)
return x
def naive_dct1(x, norm=None):
"""Calculate textbook definition version of DCT-I."""
x = np.array(x, copy=True)
N = len(x)
M = N-1
y = np.zeros(N)
m0, m = 1, 2
if norm == 'ortho':
m0 = np.sqrt(1.0/M)
m = np.sqrt(2.0/M)
for k in range(N):
for n in range(1, N-1):
y[k] += m*x[n]*np.cos(np.pi*n*k/M)
y[k] += m0 * x[0]
y[k] += m0 * x[N-1] * (1 if k % 2 == 0 else -1)
if norm == 'ortho':
y[0] *= 1/np.sqrt(2)
y[N-1] *= 1/np.sqrt(2)
return y
def naive_dst1(x, norm=None):
"""Calculate textbook definition version of DST-I."""
x = np.array(x, copy=True)
N = len(x)
M = N+1
y = np.zeros(N)
for k in range(N):
for n in range(N):
y[k] += 2*x[n]*np.sin(np.pi*(n+1.0)*(k+1.0)/M)
if norm == 'ortho':
y *= np.sqrt(0.5/M)
return y
def naive_dct4(x, norm=None):
"""Calculate textbook definition version of DCT-IV."""
x = np.array(x, copy=True)
N = len(x)
y = np.zeros(N)
for k in range(N):
for n in range(N):
y[k] += x[n]*np.cos(np.pi*(n+0.5)*(k+0.5)/(N))
if norm == 'ortho':
y *= np.sqrt(2.0/N)
else:
y *= 2
return y
def naive_dst4(x, norm=None):
"""Calculate textbook definition version of DST-IV."""
x = np.array(x, copy=True)
N = len(x)
y = np.zeros(N)
for k in range(N):
for n in range(N):
y[k] += x[n]*np.sin(np.pi*(n+0.5)*(k+0.5)/(N))
if norm == 'ortho':
y *= np.sqrt(2.0/N)
else:
y *= 2
return y
class TestComplex(object):
def test_dct_complex64(self):
y = dct(1j*np.arange(5, dtype=np.complex64))
x = 1j*dct(np.arange(5))
assert_array_almost_equal(x, y)
def test_dct_complex(self):
y = dct(np.arange(5)*1j)
x = 1j*dct(np.arange(5))
assert_array_almost_equal(x, y)
def test_idct_complex(self):
y = idct(np.arange(5)*1j)
x = 1j*idct(np.arange(5))
assert_array_almost_equal(x, y)
def test_dst_complex64(self):
y = dst(np.arange(5, dtype=np.complex64)*1j)
x = 1j*dst(np.arange(5))
assert_array_almost_equal(x, y)
def test_dst_complex(self):
y = dst(np.arange(5)*1j)
x = 1j*dst(np.arange(5))
assert_array_almost_equal(x, y)
def test_idst_complex(self):
y = idst(np.arange(5)*1j)
x = 1j*idst(np.arange(5))
assert_array_almost_equal(x, y)
class _TestDCTBase(object):
def setup_method(self):
self.rdt = None
self.dec = 14
self.type = None
def test_definition(self):
for i in FFTWDATA_SIZES:
x, yr, dt = fftw_dct_ref(self.type, i, self.rdt)
y = dct(x, type=self.type)
assert_equal(y.dtype, dt)
# XXX: we divide by np.max(y) because the tests fail otherwise. We
# should really use something like assert_array_approx_equal. The
# difference is due to fftw using a better algorithm w.r.t error
# propagation compared to the ones from fftpack.
assert_array_almost_equal(y / np.max(y), yr / np.max(y), decimal=self.dec,
err_msg="Size %d failed" % i)
def test_axis(self):
nt = 2
for i in [7, 8, 9, 16, 32, 64]:
x = np.random.randn(nt, i)
y = dct(x, type=self.type)
for j in range(nt):
assert_array_almost_equal(y[j], dct(x[j], type=self.type),
decimal=self.dec)
x = x.T
y = dct(x, axis=0, type=self.type)
for j in range(nt):
assert_array_almost_equal(y[:,j], dct(x[:,j], type=self.type),
decimal=self.dec)
class _TestDCTIBase(_TestDCTBase):
def test_definition_ortho(self):
# Test orthornomal mode.
for i in range(len(X)):
x = np.array(X[i], dtype=self.rdt)
dt = np.result_type(np.float32, self.rdt)
y = dct(x, norm='ortho', type=1)
y2 = naive_dct1(x, norm='ortho')
assert_equal(y.dtype, dt)
assert_array_almost_equal(y / np.max(y), y2 / np.max(y), decimal=self.dec)
class _TestDCTIIBase(_TestDCTBase):
def test_definition_matlab(self):
# Test correspondence with MATLAB (orthornomal mode).
for i in range(len(X)):
dt = np.result_type(np.float32, self.rdt)
x = np.array(X[i], dtype=dt)
yr = Y[i]
y = dct(x, norm="ortho", type=2)
assert_equal(y.dtype, dt)
assert_array_almost_equal(y, yr, decimal=self.dec)
class _TestDCTIIIBase(_TestDCTBase):
def test_definition_ortho(self):
# Test orthornomal mode.
for i in range(len(X)):
x = np.array(X[i], dtype=self.rdt)
dt = np.result_type(np.float32, self.rdt)
y = dct(x, norm='ortho', type=2)
xi = dct(y, norm="ortho", type=3)
assert_equal(xi.dtype, dt)
assert_array_almost_equal(xi, x, decimal=self.dec)
class _TestDCTIVBase(_TestDCTBase):
def test_definition_ortho(self):
# Test orthornomal mode.
for i in range(len(X)):
x = np.array(X[i], dtype=self.rdt)
dt = np.result_type(np.float32, self.rdt)
y = dct(x, norm='ortho', type=4)
y2 = naive_dct4(x, norm='ortho')
assert_equal(y.dtype, dt)
assert_array_almost_equal(y / np.max(y), y2 / np.max(y), decimal=self.dec)
class TestDCTIDouble(_TestDCTIBase):
def setup_method(self):
self.rdt = np.double
self.dec = 10
self.type = 1
class TestDCTIFloat(_TestDCTIBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 4
self.type = 1
class TestDCTIInt(_TestDCTIBase):
def setup_method(self):
self.rdt = int
self.dec = 5
self.type = 1
class TestDCTIIDouble(_TestDCTIIBase):
def setup_method(self):
self.rdt = np.double
self.dec = 10
self.type = 2
class TestDCTIIFloat(_TestDCTIIBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 5
self.type = 2
class TestDCTIIInt(_TestDCTIIBase):
def setup_method(self):
self.rdt = int
self.dec = 5
self.type = 2
class TestDCTIIIDouble(_TestDCTIIIBase):
def setup_method(self):
self.rdt = np.double
self.dec = 14
self.type = 3
class TestDCTIIIFloat(_TestDCTIIIBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 5
self.type = 3
class TestDCTIIIInt(_TestDCTIIIBase):
def setup_method(self):
self.rdt = int
self.dec = 5
self.type = 3
class TestDCTIVDouble(_TestDCTIVBase):
def setup_method(self):
self.rdt = np.double
self.dec = 12
self.type = 3
class TestDCTIVFloat(_TestDCTIVBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 5
self.type = 3
class TestDCTIVInt(_TestDCTIVBase):
def setup_method(self):
self.rdt = int
self.dec = 5
self.type = 3
class _TestIDCTBase(object):
def setup_method(self):
self.rdt = None
self.dec = 14
self.type = None
def test_definition(self):
for i in FFTWDATA_SIZES:
xr, yr, dt = fftw_dct_ref(self.type, i, self.rdt)
x = idct(yr, type=self.type)
if self.type == 1:
x /= 2 * (i-1)
else:
x /= 2 * i
assert_equal(x.dtype, dt)
# XXX: we divide by np.max(y) because the tests fail otherwise. We
# should really use something like assert_array_approx_equal. The
# difference is due to fftw using a better algorithm w.r.t error
# propagation compared to the ones from fftpack.
assert_array_almost_equal(x / np.max(x), xr / np.max(x), decimal=self.dec,
err_msg="Size %d failed" % i)
class TestIDCTIDouble(_TestIDCTBase):
def setup_method(self):
self.rdt = np.double
self.dec = 10
self.type = 1
class TestIDCTIFloat(_TestIDCTBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 4
self.type = 1
class TestIDCTIInt(_TestIDCTBase):
def setup_method(self):
self.rdt = int
self.dec = 4
self.type = 1
class TestIDCTIIDouble(_TestIDCTBase):
def setup_method(self):
self.rdt = np.double
self.dec = 10
self.type = 2
class TestIDCTIIFloat(_TestIDCTBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 5
self.type = 2
class TestIDCTIIInt(_TestIDCTBase):
def setup_method(self):
self.rdt = int
self.dec = 5
self.type = 2
class TestIDCTIIIDouble(_TestIDCTBase):
def setup_method(self):
self.rdt = np.double
self.dec = 14
self.type = 3
class TestIDCTIIIFloat(_TestIDCTBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 5
self.type = 3
class TestIDCTIIIInt(_TestIDCTBase):
def setup_method(self):
self.rdt = int
self.dec = 5
self.type = 3
class TestIDCTIVDouble(_TestIDCTBase):
def setup_method(self):
self.rdt = np.double
self.dec = 12
self.type = 4
class TestIDCTIVFloat(_TestIDCTBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 5
self.type = 4
class TestIDCTIVInt(_TestIDCTBase):
def setup_method(self):
self.rdt = int
self.dec = 5
self.type = 4
class _TestDSTBase(object):
def setup_method(self):
self.rdt = None # dtype
self.dec = None # number of decimals to match
self.type = None # dst type
def test_definition(self):
for i in FFTWDATA_SIZES:
xr, yr, dt = fftw_dst_ref(self.type, i, self.rdt)
y = dst(xr, type=self.type)
assert_equal(y.dtype, dt)
# XXX: we divide by np.max(y) because the tests fail otherwise. We
# should really use something like assert_array_approx_equal. The
# difference is due to fftw using a better algorithm w.r.t error
# propagation compared to the ones from fftpack.
assert_array_almost_equal(y / np.max(y), yr / np.max(y), decimal=self.dec,
err_msg="Size %d failed" % i)
class _TestDSTIBase(_TestDSTBase):
def test_definition_ortho(self):
# Test orthornomal mode.
for i in range(len(X)):
x = np.array(X[i], dtype=self.rdt)
dt = np.result_type(np.float32, self.rdt)
y = dst(x, norm='ortho', type=1)
y2 = naive_dst1(x, norm='ortho')
assert_equal(y.dtype, dt)
assert_array_almost_equal(y / np.max(y), y2 / np.max(y), decimal=self.dec)
class _TestDSTIVBase(_TestDSTBase):
def test_definition_ortho(self):
# Test orthornomal mode.
for i in range(len(X)):
x = np.array(X[i], dtype=self.rdt)
dt = np.result_type(np.float32, self.rdt)
y = dst(x, norm='ortho', type=4)
y2 = naive_dst4(x, norm='ortho')
assert_equal(y.dtype, dt)
assert_array_almost_equal(y, y2, decimal=self.dec)
class TestDSTIDouble(_TestDSTIBase):
def setup_method(self):
self.rdt = np.double
self.dec = 12
self.type = 1
class TestDSTIFloat(_TestDSTIBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 4
self.type = 1
class TestDSTIInt(_TestDSTIBase):
def setup_method(self):
self.rdt = int
self.dec = 5
self.type = 1
class TestDSTIIDouble(_TestDSTBase):
def setup_method(self):
self.rdt = np.double
self.dec = 14
self.type = 2
class TestDSTIIFloat(_TestDSTBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 6
self.type = 2
class TestDSTIIInt(_TestDSTBase):
def setup_method(self):
self.rdt = int
self.dec = 6
self.type = 2
class TestDSTIIIDouble(_TestDSTBase):
def setup_method(self):
self.rdt = np.double
self.dec = 14
self.type = 3
class TestDSTIIIFloat(_TestDSTBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 7
self.type = 3
class TestDSTIIIInt(_TestDSTBase):
def setup_method(self):
self.rdt = int
self.dec = 7
self.type = 3
class TestDSTIVDouble(_TestDSTIVBase):
def setup_method(self):
self.rdt = np.double
self.dec = 12
self.type = 4
class TestDSTIVFloat(_TestDSTIVBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 4
self.type = 4
class TestDSTIVInt(_TestDSTIVBase):
def setup_method(self):
self.rdt = int
self.dec = 5
self.type = 4
class _TestIDSTBase(object):
def setup_method(self):
self.rdt = None
self.dec = None
self.type = None
def test_definition(self):
for i in FFTWDATA_SIZES:
xr, yr, dt = fftw_dst_ref(self.type, i, self.rdt)
x = idst(yr, type=self.type)
if self.type == 1:
x /= 2 * (i+1)
else:
x /= 2 * i
assert_equal(x.dtype, dt)
# XXX: we divide by np.max(x) because the tests fail otherwise. We
# should really use something like assert_array_approx_equal. The
# difference is due to fftw using a better algorithm w.r.t error
# propagation compared to the ones from fftpack.
assert_array_almost_equal(x / np.max(x), xr / np.max(x), decimal=self.dec,
err_msg="Size %d failed" % i)
class TestIDSTIDouble(_TestIDSTBase):
def setup_method(self):
self.rdt = np.double
self.dec = 12
self.type = 1
class TestIDSTIFloat(_TestIDSTBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 4
self.type = 1
class TestIDSTIInt(_TestIDSTBase):
def setup_method(self):
self.rdt = int
self.dec = 4
self.type = 1
class TestIDSTIIDouble(_TestIDSTBase):
def setup_method(self):
self.rdt = np.double
self.dec = 14
self.type = 2
class TestIDSTIIFloat(_TestIDSTBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 6
self.type = 2
class TestIDSTIIInt(_TestIDSTBase):
def setup_method(self):
self.rdt = int
self.dec = 6
self.type = 2
class TestIDSTIIIDouble(_TestIDSTBase):
def setup_method(self):
self.rdt = np.double
self.dec = 14
self.type = 3
class TestIDSTIIIFloat(_TestIDSTBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 6
self.type = 3
class TestIDSTIIIInt(_TestIDSTBase):
def setup_method(self):
self.rdt = int
self.dec = 6
self.type = 3
class TestIDSTIVDouble(_TestIDSTBase):
def setup_method(self):
self.rdt = np.double
self.dec = 12
self.type = 4
class TestIDSTIVFloat(_TestIDSTBase):
def setup_method(self):
self.rdt = np.float32
self.dec = 6
self.type = 4
class TestIDSTIVnt(_TestIDSTBase):
def setup_method(self):
self.rdt = int
self.dec = 6
self.type = 4
class TestOverwrite(object):
"""Check input overwrite behavior."""
real_dtypes = [np.float32, np.float64]
def _check(self, x, routine, type, fftsize, axis, norm, overwrite_x, **kw):
x2 = x.copy()
routine(x2, type, fftsize, axis, norm, overwrite_x=overwrite_x)
sig = "%s(%s%r, %r, axis=%r, overwrite_x=%r)" % (
routine.__name__, x.dtype, x.shape, fftsize, axis, overwrite_x)
if not overwrite_x:
assert_equal(x2, x, err_msg="spurious overwrite in %s" % sig)
def _check_1d(self, routine, dtype, shape, axis):
np.random.seed(1234)
if np.issubdtype(dtype, np.complexfloating):
data = np.random.randn(*shape) + 1j*np.random.randn(*shape)
else:
data = np.random.randn(*shape)
data = data.astype(dtype)
for type in [1, 2, 3, 4]:
for overwrite_x in [True, False]:
for norm in [None, 'ortho']:
self._check(data, routine, type, None, axis, norm,
overwrite_x)
def test_dct(self):
for dtype in self.real_dtypes:
self._check_1d(dct, dtype, (16,), -1)
self._check_1d(dct, dtype, (16, 2), 0)
self._check_1d(dct, dtype, (2, 16), 1)
def test_idct(self):
for dtype in self.real_dtypes:
self._check_1d(idct, dtype, (16,), -1)
self._check_1d(idct, dtype, (16, 2), 0)
self._check_1d(idct, dtype, (2, 16), 1)
def test_dst(self):
for dtype in self.real_dtypes:
self._check_1d(dst, dtype, (16,), -1)
self._check_1d(dst, dtype, (16, 2), 0)
self._check_1d(dst, dtype, (2, 16), 1)
def test_idst(self):
for dtype in self.real_dtypes:
self._check_1d(idst, dtype, (16,), -1)
self._check_1d(idst, dtype, (16, 2), 0)
self._check_1d(idst, dtype, (2, 16), 1)
class Test_DCTN_IDCTN(object):
dec = 14
dct_type = [1, 2, 3, 4]
norms = [None, 'ortho']
rstate = np.random.RandomState(1234)
shape = (32, 16)
data = rstate.randn(*shape)
@pytest.mark.parametrize('fforward,finverse', [(dctn, idctn),
(dstn, idstn)])
@pytest.mark.parametrize('axes', [None,
1, (1,), [1],
0, (0,), [0],
(0, 1), [0, 1],
(-2, -1), [-2, -1]])
@pytest.mark.parametrize('dct_type', dct_type)
@pytest.mark.parametrize('norm', ['ortho'])
def test_axes_round_trip(self, fforward, finverse, axes, dct_type, norm):
tmp = fforward(self.data, type=dct_type, axes=axes, norm=norm)
tmp = finverse(tmp, type=dct_type, axes=axes, norm=norm)
assert_array_almost_equal(self.data, tmp, decimal=12)
@pytest.mark.parametrize('fforward,fforward_ref', [(dctn, dct_2d_ref),
(dstn, dst_2d_ref)])
@pytest.mark.parametrize('dct_type', dct_type)
@pytest.mark.parametrize('norm', norms)
def test_dctn_vs_2d_reference(self, fforward, fforward_ref,
dct_type, norm):
y1 = fforward(self.data, type=dct_type, axes=None, norm=norm)
y2 = fforward_ref(self.data, type=dct_type, norm=norm)
assert_array_almost_equal(y1, y2, decimal=11)
@pytest.mark.parametrize('finverse,finverse_ref', [(idctn, idct_2d_ref),
(idstn, idst_2d_ref)])
@pytest.mark.parametrize('dct_type', dct_type)
@pytest.mark.parametrize('norm', [None, 'ortho'])
def test_idctn_vs_2d_reference(self, finverse, finverse_ref,
dct_type, norm):
fdata = dctn(self.data, type=dct_type, norm=norm)
y1 = finverse(fdata, type=dct_type, norm=norm)
y2 = finverse_ref(fdata, type=dct_type, norm=norm)
assert_array_almost_equal(y1, y2, decimal=11)
@pytest.mark.parametrize('fforward,finverse', [(dctn, idctn),
(dstn, idstn)])
def test_axes_and_shape(self, fforward, finverse):
with assert_raises(ValueError,
match="when given, axes and shape arguments"
" have to be of the same length"):
fforward(self.data, shape=self.data.shape[0], axes=(0, 1))
with assert_raises(ValueError,
match="when given, axes and shape arguments"
" have to be of the same length"):
fforward(self.data, shape=self.data.shape[0], axes=None)
with assert_raises(ValueError,
match="when given, axes and shape arguments"
" have to be of the same length"):
fforward(self.data, shape=self.data.shape, axes=0)
@pytest.mark.parametrize('fforward', [dctn, dstn])
def test_shape(self, fforward):
tmp = fforward(self.data, shape=(128, 128), axes=None)
assert_equal(tmp.shape, (128, 128))
@pytest.mark.parametrize('fforward,finverse', [(dctn, idctn),
(dstn, idstn)])
@pytest.mark.parametrize('axes', [1, (1,), [1],
0, (0,), [0]])
def test_shape_is_none_with_axes(self, fforward, finverse, axes):
tmp = fforward(self.data, shape=None, axes=axes, norm='ortho')
tmp = finverse(tmp, shape=None, axes=axes, norm='ortho')
assert_array_almost_equal(self.data, tmp, decimal=self.dec)