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diff --git a/.venv/lib/python3.12/site-packages/numpy/fft/__init__.py b/.venv/lib/python3.12/site-packages/numpy/fft/__init__.py new file mode 100644 index 00000000..fd5e4758 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/numpy/fft/__init__.py @@ -0,0 +1,212 @@ +""" +Discrete Fourier Transform (:mod:`numpy.fft`) +============================================= + +.. currentmodule:: numpy.fft + +The SciPy module `scipy.fft` is a more comprehensive superset +of ``numpy.fft``, which includes only a basic set of routines. + +Standard FFTs +------------- + +.. autosummary:: + :toctree: generated/ + + fft Discrete Fourier transform. + ifft Inverse discrete Fourier transform. + fft2 Discrete Fourier transform in two dimensions. + ifft2 Inverse discrete Fourier transform in two dimensions. + fftn Discrete Fourier transform in N-dimensions. + ifftn Inverse discrete Fourier transform in N dimensions. + +Real FFTs +--------- + +.. autosummary:: + :toctree: generated/ + + rfft Real discrete Fourier transform. + irfft Inverse real discrete Fourier transform. + rfft2 Real discrete Fourier transform in two dimensions. + irfft2 Inverse real discrete Fourier transform in two dimensions. + rfftn Real discrete Fourier transform in N dimensions. + irfftn Inverse real discrete Fourier transform in N dimensions. + +Hermitian FFTs +-------------- + +.. autosummary:: + :toctree: generated/ + + hfft Hermitian discrete Fourier transform. + ihfft Inverse Hermitian discrete Fourier transform. + +Helper routines +--------------- + +.. autosummary:: + :toctree: generated/ + + fftfreq Discrete Fourier Transform sample frequencies. + rfftfreq DFT sample frequencies (for usage with rfft, irfft). + fftshift Shift zero-frequency component to center of spectrum. + ifftshift Inverse of fftshift. + + +Background information +---------------------- + +Fourier analysis is fundamentally a method for expressing a function as a +sum of periodic components, and for recovering the function from those +components. When both the function and its Fourier transform are +replaced with discretized counterparts, it is called the discrete Fourier +transform (DFT). The DFT has become a mainstay of numerical computing in +part because of a very fast algorithm for computing it, called the Fast +Fourier Transform (FFT), which was known to Gauss (1805) and was brought +to light in its current form by Cooley and Tukey [CT]_. Press et al. [NR]_ +provide an accessible introduction to Fourier analysis and its +applications. + +Because the discrete Fourier transform separates its input into +components that contribute at discrete frequencies, it has a great number +of applications in digital signal processing, e.g., for filtering, and in +this context the discretized input to the transform is customarily +referred to as a *signal*, which exists in the *time domain*. The output +is called a *spectrum* or *transform* and exists in the *frequency +domain*. + +Implementation details +---------------------- + +There are many ways to define the DFT, varying in the sign of the +exponent, normalization, etc. In this implementation, the DFT is defined +as + +.. math:: + A_k = \\sum_{m=0}^{n-1} a_m \\exp\\left\\{-2\\pi i{mk \\over n}\\right\\} + \\qquad k = 0,\\ldots,n-1. + +The DFT is in general defined for complex inputs and outputs, and a +single-frequency component at linear frequency :math:`f` is +represented by a complex exponential +:math:`a_m = \\exp\\{2\\pi i\\,f m\\Delta t\\}`, where :math:`\\Delta t` +is the sampling interval. + +The values in the result follow so-called "standard" order: If ``A = +fft(a, n)``, then ``A[0]`` contains the zero-frequency term (the sum of +the signal), which is always purely real for real inputs. Then ``A[1:n/2]`` +contains the positive-frequency terms, and ``A[n/2+1:]`` contains the +negative-frequency terms, in order of decreasingly negative frequency. +For an even number of input points, ``A[n/2]`` represents both positive and +negative Nyquist frequency, and is also purely real for real input. For +an odd number of input points, ``A[(n-1)/2]`` contains the largest positive +frequency, while ``A[(n+1)/2]`` contains the largest negative frequency. +The routine ``np.fft.fftfreq(n)`` returns an array giving the frequencies +of corresponding elements in the output. The routine +``np.fft.fftshift(A)`` shifts transforms and their frequencies to put the +zero-frequency components in the middle, and ``np.fft.ifftshift(A)`` undoes +that shift. + +When the input `a` is a time-domain signal and ``A = fft(a)``, ``np.abs(A)`` +is its amplitude spectrum and ``np.abs(A)**2`` is its power spectrum. +The phase spectrum is obtained by ``np.angle(A)``. + +The inverse DFT is defined as + +.. math:: + a_m = \\frac{1}{n}\\sum_{k=0}^{n-1}A_k\\exp\\left\\{2\\pi i{mk\\over n}\\right\\} + \\qquad m = 0,\\ldots,n-1. + +It differs from the forward transform by the sign of the exponential +argument and the default normalization by :math:`1/n`. + +Type Promotion +-------------- + +`numpy.fft` promotes ``float32`` and ``complex64`` arrays to ``float64`` and +``complex128`` arrays respectively. For an FFT implementation that does not +promote input arrays, see `scipy.fftpack`. + +Normalization +------------- + +The argument ``norm`` indicates which direction of the pair of direct/inverse +transforms is scaled and with what normalization factor. +The default normalization (``"backward"``) has the direct (forward) transforms +unscaled and the inverse (backward) transforms scaled by :math:`1/n`. It is +possible to obtain unitary transforms by setting the keyword argument ``norm`` +to ``"ortho"`` so that both direct and inverse transforms are scaled by +:math:`1/\\sqrt{n}`. Finally, setting the keyword argument ``norm`` to +``"forward"`` has the direct transforms scaled by :math:`1/n` and the inverse +transforms unscaled (i.e. exactly opposite to the default ``"backward"``). +`None` is an alias of the default option ``"backward"`` for backward +compatibility. + +Real and Hermitian transforms +----------------------------- + +When the input is purely real, its transform is Hermitian, i.e., the +component at frequency :math:`f_k` is the complex conjugate of the +component at frequency :math:`-f_k`, which means that for real +inputs there is no information in the negative frequency components that +is not already available from the positive frequency components. +The family of `rfft` functions is +designed to operate on real inputs, and exploits this symmetry by +computing only the positive frequency components, up to and including the +Nyquist frequency. Thus, ``n`` input points produce ``n/2+1`` complex +output points. The inverses of this family assumes the same symmetry of +its input, and for an output of ``n`` points uses ``n/2+1`` input points. + +Correspondingly, when the spectrum is purely real, the signal is +Hermitian. The `hfft` family of functions exploits this symmetry by +using ``n/2+1`` complex points in the input (time) domain for ``n`` real +points in the frequency domain. + +In higher dimensions, FFTs are used, e.g., for image analysis and +filtering. The computational efficiency of the FFT means that it can +also be a faster way to compute large convolutions, using the property +that a convolution in the time domain is equivalent to a point-by-point +multiplication in the frequency domain. + +Higher dimensions +----------------- + +In two dimensions, the DFT is defined as + +.. math:: + A_{kl} = \\sum_{m=0}^{M-1} \\sum_{n=0}^{N-1} + a_{mn}\\exp\\left\\{-2\\pi i \\left({mk\\over M}+{nl\\over N}\\right)\\right\\} + \\qquad k = 0, \\ldots, M-1;\\quad l = 0, \\ldots, N-1, + +which extends in the obvious way to higher dimensions, and the inverses +in higher dimensions also extend in the same way. + +References +---------- + +.. [CT] Cooley, James W., and John W. Tukey, 1965, "An algorithm for the + machine calculation of complex Fourier series," *Math. Comput.* + 19: 297-301. + +.. [NR] Press, W., Teukolsky, S., Vetterline, W.T., and Flannery, B.P., + 2007, *Numerical Recipes: The Art of Scientific Computing*, ch. + 12-13. Cambridge Univ. Press, Cambridge, UK. + +Examples +-------- + +For examples, see the various functions. + +""" + +from . import _pocketfft, helper +from ._pocketfft import * +from .helper import * + +__all__ = _pocketfft.__all__.copy() +__all__ += helper.__all__ + +from numpy._pytesttester import PytestTester +test = PytestTester(__name__) +del PytestTester diff --git a/.venv/lib/python3.12/site-packages/numpy/fft/__init__.pyi b/.venv/lib/python3.12/site-packages/numpy/fft/__init__.pyi new file mode 100644 index 00000000..5518aac1 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/numpy/fft/__init__.pyi @@ -0,0 +1,29 @@ +from numpy._pytesttester import PytestTester + +from numpy.fft._pocketfft import ( + fft as fft, + ifft as ifft, + rfft as rfft, + irfft as irfft, + hfft as hfft, + ihfft as ihfft, + rfftn as rfftn, + irfftn as irfftn, + rfft2 as rfft2, + irfft2 as irfft2, + fft2 as fft2, + ifft2 as ifft2, + fftn as fftn, + ifftn as ifftn, +) + +from numpy.fft.helper import ( + fftshift as fftshift, + ifftshift as ifftshift, + fftfreq as fftfreq, + rfftfreq as rfftfreq, +) + +__all__: list[str] +__path__: list[str] +test: PytestTester diff --git a/.venv/lib/python3.12/site-packages/numpy/fft/_pocketfft.py b/.venv/lib/python3.12/site-packages/numpy/fft/_pocketfft.py new file mode 100644 index 00000000..ad69f7c8 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/numpy/fft/_pocketfft.py @@ -0,0 +1,1424 @@ +""" +Discrete Fourier Transforms + +Routines in this module: + +fft(a, n=None, axis=-1, norm="backward") +ifft(a, n=None, axis=-1, norm="backward") +rfft(a, n=None, axis=-1, norm="backward") +irfft(a, n=None, axis=-1, norm="backward") +hfft(a, n=None, axis=-1, norm="backward") +ihfft(a, n=None, axis=-1, norm="backward") +fftn(a, s=None, axes=None, norm="backward") +ifftn(a, s=None, axes=None, norm="backward") +rfftn(a, s=None, axes=None, norm="backward") +irfftn(a, s=None, axes=None, norm="backward") +fft2(a, s=None, axes=(-2,-1), norm="backward") +ifft2(a, s=None, axes=(-2, -1), norm="backward") +rfft2(a, s=None, axes=(-2,-1), norm="backward") +irfft2(a, s=None, axes=(-2, -1), norm="backward") + +i = inverse transform +r = transform of purely real data +h = Hermite transform +n = n-dimensional transform +2 = 2-dimensional transform +(Note: 2D routines are just nD routines with different default +behavior.) + +""" +__all__ = ['fft', 'ifft', 'rfft', 'irfft', 'hfft', 'ihfft', 'rfftn', + 'irfftn', 'rfft2', 'irfft2', 'fft2', 'ifft2', 'fftn', 'ifftn'] + +import functools + +from numpy.core import asarray, zeros, swapaxes, conjugate, take, sqrt +from . import _pocketfft_internal as pfi +from numpy.core.multiarray import normalize_axis_index +from numpy.core import overrides + + +array_function_dispatch = functools.partial( + overrides.array_function_dispatch, module='numpy.fft') + + +# `inv_norm` is a float by which the result of the transform needs to be +# divided. This replaces the original, more intuitive 'fct` parameter to avoid +# divisions by zero (or alternatively additional checks) in the case of +# zero-length axes during its computation. +def _raw_fft(a, n, axis, is_real, is_forward, inv_norm): + axis = normalize_axis_index(axis, a.ndim) + if n is None: + n = a.shape[axis] + + fct = 1/inv_norm + + if a.shape[axis] != n: + s = list(a.shape) + index = [slice(None)]*len(s) + if s[axis] > n: + index[axis] = slice(0, n) + a = a[tuple(index)] + else: + index[axis] = slice(0, s[axis]) + s[axis] = n + z = zeros(s, a.dtype.char) + z[tuple(index)] = a + a = z + + if axis == a.ndim-1: + r = pfi.execute(a, is_real, is_forward, fct) + else: + a = swapaxes(a, axis, -1) + r = pfi.execute(a, is_real, is_forward, fct) + r = swapaxes(r, axis, -1) + return r + + +def _get_forward_norm(n, norm): + if n < 1: + raise ValueError(f"Invalid number of FFT data points ({n}) specified.") + + if norm is None or norm == "backward": + return 1 + elif norm == "ortho": + return sqrt(n) + elif norm == "forward": + return n + raise ValueError(f'Invalid norm value {norm}; should be "backward",' + '"ortho" or "forward".') + + +def _get_backward_norm(n, norm): + if n < 1: + raise ValueError(f"Invalid number of FFT data points ({n}) specified.") + + if norm is None or norm == "backward": + return n + elif norm == "ortho": + return sqrt(n) + elif norm == "forward": + return 1 + raise ValueError(f'Invalid norm value {norm}; should be "backward", ' + '"ortho" or "forward".') + + +_SWAP_DIRECTION_MAP = {"backward": "forward", None: "forward", + "ortho": "ortho", "forward": "backward"} + + +def _swap_direction(norm): + try: + return _SWAP_DIRECTION_MAP[norm] + except KeyError: + raise ValueError(f'Invalid norm value {norm}; should be "backward", ' + '"ortho" or "forward".') from None + + +def _fft_dispatcher(a, n=None, axis=None, norm=None): + return (a,) + + +@array_function_dispatch(_fft_dispatcher) +def fft(a, n=None, axis=-1, norm=None): + """ + Compute the one-dimensional discrete Fourier Transform. + + This function computes the one-dimensional *n*-point discrete Fourier + Transform (DFT) with the efficient Fast Fourier Transform (FFT) + algorithm [CT]. + + Parameters + ---------- + a : array_like + Input array, can be complex. + n : int, optional + Length of the transformed axis of the output. + If `n` is smaller than the length of the input, the input is cropped. + If it is larger, the input is padded with zeros. If `n` is not given, + the length of the input along the axis specified by `axis` is used. + axis : int, optional + Axis over which to compute the FFT. If not given, the last axis is + used. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : complex ndarray + The truncated or zero-padded input, transformed along the axis + indicated by `axis`, or the last one if `axis` is not specified. + + Raises + ------ + IndexError + If `axis` is not a valid axis of `a`. + + See Also + -------- + numpy.fft : for definition of the DFT and conventions used. + ifft : The inverse of `fft`. + fft2 : The two-dimensional FFT. + fftn : The *n*-dimensional FFT. + rfftn : The *n*-dimensional FFT of real input. + fftfreq : Frequency bins for given FFT parameters. + + Notes + ----- + FFT (Fast Fourier Transform) refers to a way the discrete Fourier + Transform (DFT) can be calculated efficiently, by using symmetries in the + calculated terms. The symmetry is highest when `n` is a power of 2, and + the transform is therefore most efficient for these sizes. + + The DFT is defined, with the conventions used in this implementation, in + the documentation for the `numpy.fft` module. + + References + ---------- + .. [CT] Cooley, James W., and John W. Tukey, 1965, "An algorithm for the + machine calculation of complex Fourier series," *Math. Comput.* + 19: 297-301. + + Examples + -------- + >>> np.fft.fft(np.exp(2j * np.pi * np.arange(8) / 8)) + array([-2.33486982e-16+1.14423775e-17j, 8.00000000e+00-1.25557246e-15j, + 2.33486982e-16+2.33486982e-16j, 0.00000000e+00+1.22464680e-16j, + -1.14423775e-17+2.33486982e-16j, 0.00000000e+00+5.20784380e-16j, + 1.14423775e-17+1.14423775e-17j, 0.00000000e+00+1.22464680e-16j]) + + In this example, real input has an FFT which is Hermitian, i.e., symmetric + in the real part and anti-symmetric in the imaginary part, as described in + the `numpy.fft` documentation: + + >>> import matplotlib.pyplot as plt + >>> t = np.arange(256) + >>> sp = np.fft.fft(np.sin(t)) + >>> freq = np.fft.fftfreq(t.shape[-1]) + >>> plt.plot(freq, sp.real, freq, sp.imag) + [<matplotlib.lines.Line2D object at 0x...>, <matplotlib.lines.Line2D object at 0x...>] + >>> plt.show() + + """ + a = asarray(a) + if n is None: + n = a.shape[axis] + inv_norm = _get_forward_norm(n, norm) + output = _raw_fft(a, n, axis, False, True, inv_norm) + return output + + +@array_function_dispatch(_fft_dispatcher) +def ifft(a, n=None, axis=-1, norm=None): + """ + Compute the one-dimensional inverse discrete Fourier Transform. + + This function computes the inverse of the one-dimensional *n*-point + discrete Fourier transform computed by `fft`. In other words, + ``ifft(fft(a)) == a`` to within numerical accuracy. + For a general description of the algorithm and definitions, + see `numpy.fft`. + + The input should be ordered in the same way as is returned by `fft`, + i.e., + + * ``a[0]`` should contain the zero frequency term, + * ``a[1:n//2]`` should contain the positive-frequency terms, + * ``a[n//2 + 1:]`` should contain the negative-frequency terms, in + increasing order starting from the most negative frequency. + + For an even number of input points, ``A[n//2]`` represents the sum of + the values at the positive and negative Nyquist frequencies, as the two + are aliased together. See `numpy.fft` for details. + + Parameters + ---------- + a : array_like + Input array, can be complex. + n : int, optional + Length of the transformed axis of the output. + If `n` is smaller than the length of the input, the input is cropped. + If it is larger, the input is padded with zeros. If `n` is not given, + the length of the input along the axis specified by `axis` is used. + See notes about padding issues. + axis : int, optional + Axis over which to compute the inverse DFT. If not given, the last + axis is used. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : complex ndarray + The truncated or zero-padded input, transformed along the axis + indicated by `axis`, or the last one if `axis` is not specified. + + Raises + ------ + IndexError + If `axis` is not a valid axis of `a`. + + See Also + -------- + numpy.fft : An introduction, with definitions and general explanations. + fft : The one-dimensional (forward) FFT, of which `ifft` is the inverse + ifft2 : The two-dimensional inverse FFT. + ifftn : The n-dimensional inverse FFT. + + Notes + ----- + If the input parameter `n` is larger than the size of the input, the input + is padded by appending zeros at the end. Even though this is the common + approach, it might lead to surprising results. If a different padding is + desired, it must be performed before calling `ifft`. + + Examples + -------- + >>> np.fft.ifft([0, 4, 0, 0]) + array([ 1.+0.j, 0.+1.j, -1.+0.j, 0.-1.j]) # may vary + + Create and plot a band-limited signal with random phases: + + >>> import matplotlib.pyplot as plt + >>> t = np.arange(400) + >>> n = np.zeros((400,), dtype=complex) + >>> n[40:60] = np.exp(1j*np.random.uniform(0, 2*np.pi, (20,))) + >>> s = np.fft.ifft(n) + >>> plt.plot(t, s.real, label='real') + [<matplotlib.lines.Line2D object at ...>] + >>> plt.plot(t, s.imag, '--', label='imaginary') + [<matplotlib.lines.Line2D object at ...>] + >>> plt.legend() + <matplotlib.legend.Legend object at ...> + >>> plt.show() + + """ + a = asarray(a) + if n is None: + n = a.shape[axis] + inv_norm = _get_backward_norm(n, norm) + output = _raw_fft(a, n, axis, False, False, inv_norm) + return output + + +@array_function_dispatch(_fft_dispatcher) +def rfft(a, n=None, axis=-1, norm=None): + """ + Compute the one-dimensional discrete Fourier Transform for real input. + + This function computes the one-dimensional *n*-point discrete Fourier + Transform (DFT) of a real-valued array by means of an efficient algorithm + called the Fast Fourier Transform (FFT). + + Parameters + ---------- + a : array_like + Input array + n : int, optional + Number of points along transformation axis in the input to use. + If `n` is smaller than the length of the input, the input is cropped. + If it is larger, the input is padded with zeros. If `n` is not given, + the length of the input along the axis specified by `axis` is used. + axis : int, optional + Axis over which to compute the FFT. If not given, the last axis is + used. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : complex ndarray + The truncated or zero-padded input, transformed along the axis + indicated by `axis`, or the last one if `axis` is not specified. + If `n` is even, the length of the transformed axis is ``(n/2)+1``. + If `n` is odd, the length is ``(n+1)/2``. + + Raises + ------ + IndexError + If `axis` is not a valid axis of `a`. + + See Also + -------- + numpy.fft : For definition of the DFT and conventions used. + irfft : The inverse of `rfft`. + fft : The one-dimensional FFT of general (complex) input. + fftn : The *n*-dimensional FFT. + rfftn : The *n*-dimensional FFT of real input. + + Notes + ----- + When the DFT is computed for purely real input, the output is + Hermitian-symmetric, i.e. the negative frequency terms are just the complex + conjugates of the corresponding positive-frequency terms, and the + negative-frequency terms are therefore redundant. This function does not + compute the negative frequency terms, and the length of the transformed + axis of the output is therefore ``n//2 + 1``. + + When ``A = rfft(a)`` and fs is the sampling frequency, ``A[0]`` contains + the zero-frequency term 0*fs, which is real due to Hermitian symmetry. + + If `n` is even, ``A[-1]`` contains the term representing both positive + and negative Nyquist frequency (+fs/2 and -fs/2), and must also be purely + real. If `n` is odd, there is no term at fs/2; ``A[-1]`` contains + the largest positive frequency (fs/2*(n-1)/n), and is complex in the + general case. + + If the input `a` contains an imaginary part, it is silently discarded. + + Examples + -------- + >>> np.fft.fft([0, 1, 0, 0]) + array([ 1.+0.j, 0.-1.j, -1.+0.j, 0.+1.j]) # may vary + >>> np.fft.rfft([0, 1, 0, 0]) + array([ 1.+0.j, 0.-1.j, -1.+0.j]) # may vary + + Notice how the final element of the `fft` output is the complex conjugate + of the second element, for real input. For `rfft`, this symmetry is + exploited to compute only the non-negative frequency terms. + + """ + a = asarray(a) + if n is None: + n = a.shape[axis] + inv_norm = _get_forward_norm(n, norm) + output = _raw_fft(a, n, axis, True, True, inv_norm) + return output + + +@array_function_dispatch(_fft_dispatcher) +def irfft(a, n=None, axis=-1, norm=None): + """ + Computes the inverse of `rfft`. + + This function computes the inverse of the one-dimensional *n*-point + discrete Fourier Transform of real input computed by `rfft`. + In other words, ``irfft(rfft(a), len(a)) == a`` to within numerical + accuracy. (See Notes below for why ``len(a)`` is necessary here.) + + The input is expected to be in the form returned by `rfft`, i.e. the + real zero-frequency term followed by the complex positive frequency terms + in order of increasing frequency. Since the discrete Fourier Transform of + real input is Hermitian-symmetric, the negative frequency terms are taken + to be the complex conjugates of the corresponding positive frequency terms. + + Parameters + ---------- + a : array_like + The input array. + n : int, optional + Length of the transformed axis of the output. + For `n` output points, ``n//2+1`` input points are necessary. If the + input is longer than this, it is cropped. If it is shorter than this, + it is padded with zeros. If `n` is not given, it is taken to be + ``2*(m-1)`` where ``m`` is the length of the input along the axis + specified by `axis`. + axis : int, optional + Axis over which to compute the inverse FFT. If not given, the last + axis is used. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : ndarray + The truncated or zero-padded input, transformed along the axis + indicated by `axis`, or the last one if `axis` is not specified. + The length of the transformed axis is `n`, or, if `n` is not given, + ``2*(m-1)`` where ``m`` is the length of the transformed axis of the + input. To get an odd number of output points, `n` must be specified. + + Raises + ------ + IndexError + If `axis` is not a valid axis of `a`. + + See Also + -------- + numpy.fft : For definition of the DFT and conventions used. + rfft : The one-dimensional FFT of real input, of which `irfft` is inverse. + fft : The one-dimensional FFT. + irfft2 : The inverse of the two-dimensional FFT of real input. + irfftn : The inverse of the *n*-dimensional FFT of real input. + + Notes + ----- + Returns the real valued `n`-point inverse discrete Fourier transform + of `a`, where `a` contains the non-negative frequency terms of a + Hermitian-symmetric sequence. `n` is the length of the result, not the + input. + + If you specify an `n` such that `a` must be zero-padded or truncated, the + extra/removed values will be added/removed at high frequencies. One can + thus resample a series to `m` points via Fourier interpolation by: + ``a_resamp = irfft(rfft(a), m)``. + + The correct interpretation of the hermitian input depends on the length of + the original data, as given by `n`. This is because each input shape could + correspond to either an odd or even length signal. By default, `irfft` + assumes an even output length which puts the last entry at the Nyquist + frequency; aliasing with its symmetric counterpart. By Hermitian symmetry, + the value is thus treated as purely real. To avoid losing information, the + correct length of the real input **must** be given. + + Examples + -------- + >>> np.fft.ifft([1, -1j, -1, 1j]) + array([0.+0.j, 1.+0.j, 0.+0.j, 0.+0.j]) # may vary + >>> np.fft.irfft([1, -1j, -1]) + array([0., 1., 0., 0.]) + + Notice how the last term in the input to the ordinary `ifft` is the + complex conjugate of the second term, and the output has zero imaginary + part everywhere. When calling `irfft`, the negative frequencies are not + specified, and the output array is purely real. + + """ + a = asarray(a) + if n is None: + n = (a.shape[axis] - 1) * 2 + inv_norm = _get_backward_norm(n, norm) + output = _raw_fft(a, n, axis, True, False, inv_norm) + return output + + +@array_function_dispatch(_fft_dispatcher) +def hfft(a, n=None, axis=-1, norm=None): + """ + Compute the FFT of a signal that has Hermitian symmetry, i.e., a real + spectrum. + + Parameters + ---------- + a : array_like + The input array. + n : int, optional + Length of the transformed axis of the output. For `n` output + points, ``n//2 + 1`` input points are necessary. If the input is + longer than this, it is cropped. If it is shorter than this, it is + padded with zeros. If `n` is not given, it is taken to be ``2*(m-1)`` + where ``m`` is the length of the input along the axis specified by + `axis`. + axis : int, optional + Axis over which to compute the FFT. If not given, the last + axis is used. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : ndarray + The truncated or zero-padded input, transformed along the axis + indicated by `axis`, or the last one if `axis` is not specified. + The length of the transformed axis is `n`, or, if `n` is not given, + ``2*m - 2`` where ``m`` is the length of the transformed axis of + the input. To get an odd number of output points, `n` must be + specified, for instance as ``2*m - 1`` in the typical case, + + Raises + ------ + IndexError + If `axis` is not a valid axis of `a`. + + See also + -------- + rfft : Compute the one-dimensional FFT for real input. + ihfft : The inverse of `hfft`. + + Notes + ----- + `hfft`/`ihfft` are a pair analogous to `rfft`/`irfft`, but for the + opposite case: here the signal has Hermitian symmetry in the time + domain and is real in the frequency domain. So here it's `hfft` for + which you must supply the length of the result if it is to be odd. + + * even: ``ihfft(hfft(a, 2*len(a) - 2)) == a``, within roundoff error, + * odd: ``ihfft(hfft(a, 2*len(a) - 1)) == a``, within roundoff error. + + The correct interpretation of the hermitian input depends on the length of + the original data, as given by `n`. This is because each input shape could + correspond to either an odd or even length signal. By default, `hfft` + assumes an even output length which puts the last entry at the Nyquist + frequency; aliasing with its symmetric counterpart. By Hermitian symmetry, + the value is thus treated as purely real. To avoid losing information, the + shape of the full signal **must** be given. + + Examples + -------- + >>> signal = np.array([1, 2, 3, 4, 3, 2]) + >>> np.fft.fft(signal) + array([15.+0.j, -4.+0.j, 0.+0.j, -1.-0.j, 0.+0.j, -4.+0.j]) # may vary + >>> np.fft.hfft(signal[:4]) # Input first half of signal + array([15., -4., 0., -1., 0., -4.]) + >>> np.fft.hfft(signal, 6) # Input entire signal and truncate + array([15., -4., 0., -1., 0., -4.]) + + + >>> signal = np.array([[1, 1.j], [-1.j, 2]]) + >>> np.conj(signal.T) - signal # check Hermitian symmetry + array([[ 0.-0.j, -0.+0.j], # may vary + [ 0.+0.j, 0.-0.j]]) + >>> freq_spectrum = np.fft.hfft(signal) + >>> freq_spectrum + array([[ 1., 1.], + [ 2., -2.]]) + + """ + a = asarray(a) + if n is None: + n = (a.shape[axis] - 1) * 2 + new_norm = _swap_direction(norm) + output = irfft(conjugate(a), n, axis, norm=new_norm) + return output + + +@array_function_dispatch(_fft_dispatcher) +def ihfft(a, n=None, axis=-1, norm=None): + """ + Compute the inverse FFT of a signal that has Hermitian symmetry. + + Parameters + ---------- + a : array_like + Input array. + n : int, optional + Length of the inverse FFT, the number of points along + transformation axis in the input to use. If `n` is smaller than + the length of the input, the input is cropped. If it is larger, + the input is padded with zeros. If `n` is not given, the length of + the input along the axis specified by `axis` is used. + axis : int, optional + Axis over which to compute the inverse FFT. If not given, the last + axis is used. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : complex ndarray + The truncated or zero-padded input, transformed along the axis + indicated by `axis`, or the last one if `axis` is not specified. + The length of the transformed axis is ``n//2 + 1``. + + See also + -------- + hfft, irfft + + Notes + ----- + `hfft`/`ihfft` are a pair analogous to `rfft`/`irfft`, but for the + opposite case: here the signal has Hermitian symmetry in the time + domain and is real in the frequency domain. So here it's `hfft` for + which you must supply the length of the result if it is to be odd: + + * even: ``ihfft(hfft(a, 2*len(a) - 2)) == a``, within roundoff error, + * odd: ``ihfft(hfft(a, 2*len(a) - 1)) == a``, within roundoff error. + + Examples + -------- + >>> spectrum = np.array([ 15, -4, 0, -1, 0, -4]) + >>> np.fft.ifft(spectrum) + array([1.+0.j, 2.+0.j, 3.+0.j, 4.+0.j, 3.+0.j, 2.+0.j]) # may vary + >>> np.fft.ihfft(spectrum) + array([ 1.-0.j, 2.-0.j, 3.-0.j, 4.-0.j]) # may vary + + """ + a = asarray(a) + if n is None: + n = a.shape[axis] + new_norm = _swap_direction(norm) + output = conjugate(rfft(a, n, axis, norm=new_norm)) + return output + + +def _cook_nd_args(a, s=None, axes=None, invreal=0): + if s is None: + shapeless = 1 + if axes is None: + s = list(a.shape) + else: + s = take(a.shape, axes) + else: + shapeless = 0 + s = list(s) + if axes is None: + axes = list(range(-len(s), 0)) + if len(s) != len(axes): + raise ValueError("Shape and axes have different lengths.") + if invreal and shapeless: + s[-1] = (a.shape[axes[-1]] - 1) * 2 + return s, axes + + +def _raw_fftnd(a, s=None, axes=None, function=fft, norm=None): + a = asarray(a) + s, axes = _cook_nd_args(a, s, axes) + itl = list(range(len(axes))) + itl.reverse() + for ii in itl: + a = function(a, n=s[ii], axis=axes[ii], norm=norm) + return a + + +def _fftn_dispatcher(a, s=None, axes=None, norm=None): + return (a,) + + +@array_function_dispatch(_fftn_dispatcher) +def fftn(a, s=None, axes=None, norm=None): + """ + Compute the N-dimensional discrete Fourier Transform. + + This function computes the *N*-dimensional discrete Fourier Transform over + any number of axes in an *M*-dimensional array by means of the Fast Fourier + Transform (FFT). + + Parameters + ---------- + a : array_like + Input array, can be complex. + s : sequence of ints, optional + Shape (length of each transformed axis) of the output + (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.). + This corresponds to ``n`` for ``fft(x, n)``. + Along any axis, if the given shape is smaller than that of the input, + the input is cropped. If it is larger, the input is padded with zeros. + if `s` is not given, the shape of the input along the axes specified + by `axes` is used. + axes : sequence of ints, optional + Axes over which to compute the FFT. If not given, the last ``len(s)`` + axes are used, or all axes if `s` is also not specified. + Repeated indices in `axes` means that the transform over that axis is + performed multiple times. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : complex ndarray + The truncated or zero-padded input, transformed along the axes + indicated by `axes`, or by a combination of `s` and `a`, + as explained in the parameters section above. + + Raises + ------ + ValueError + If `s` and `axes` have different length. + IndexError + If an element of `axes` is larger than than the number of axes of `a`. + + See Also + -------- + numpy.fft : Overall view of discrete Fourier transforms, with definitions + and conventions used. + ifftn : The inverse of `fftn`, the inverse *n*-dimensional FFT. + fft : The one-dimensional FFT, with definitions and conventions used. + rfftn : The *n*-dimensional FFT of real input. + fft2 : The two-dimensional FFT. + fftshift : Shifts zero-frequency terms to centre of array + + Notes + ----- + The output, analogously to `fft`, contains the term for zero frequency in + the low-order corner of all axes, the positive frequency terms in the + first half of all axes, the term for the Nyquist frequency in the middle + of all axes and the negative frequency terms in the second half of all + axes, in order of decreasingly negative frequency. + + See `numpy.fft` for details, definitions and conventions used. + + Examples + -------- + >>> a = np.mgrid[:3, :3, :3][0] + >>> np.fft.fftn(a, axes=(1, 2)) + array([[[ 0.+0.j, 0.+0.j, 0.+0.j], # may vary + [ 0.+0.j, 0.+0.j, 0.+0.j], + [ 0.+0.j, 0.+0.j, 0.+0.j]], + [[ 9.+0.j, 0.+0.j, 0.+0.j], + [ 0.+0.j, 0.+0.j, 0.+0.j], + [ 0.+0.j, 0.+0.j, 0.+0.j]], + [[18.+0.j, 0.+0.j, 0.+0.j], + [ 0.+0.j, 0.+0.j, 0.+0.j], + [ 0.+0.j, 0.+0.j, 0.+0.j]]]) + >>> np.fft.fftn(a, (2, 2), axes=(0, 1)) + array([[[ 2.+0.j, 2.+0.j, 2.+0.j], # may vary + [ 0.+0.j, 0.+0.j, 0.+0.j]], + [[-2.+0.j, -2.+0.j, -2.+0.j], + [ 0.+0.j, 0.+0.j, 0.+0.j]]]) + + >>> import matplotlib.pyplot as plt + >>> [X, Y] = np.meshgrid(2 * np.pi * np.arange(200) / 12, + ... 2 * np.pi * np.arange(200) / 34) + >>> S = np.sin(X) + np.cos(Y) + np.random.uniform(0, 1, X.shape) + >>> FS = np.fft.fftn(S) + >>> plt.imshow(np.log(np.abs(np.fft.fftshift(FS))**2)) + <matplotlib.image.AxesImage object at 0x...> + >>> plt.show() + + """ + return _raw_fftnd(a, s, axes, fft, norm) + + +@array_function_dispatch(_fftn_dispatcher) +def ifftn(a, s=None, axes=None, norm=None): + """ + Compute the N-dimensional inverse discrete Fourier Transform. + + This function computes the inverse of the N-dimensional discrete + Fourier Transform over any number of axes in an M-dimensional array by + means of the Fast Fourier Transform (FFT). In other words, + ``ifftn(fftn(a)) == a`` to within numerical accuracy. + For a description of the definitions and conventions used, see `numpy.fft`. + + The input, analogously to `ifft`, should be ordered in the same way as is + returned by `fftn`, i.e. it should have the term for zero frequency + in all axes in the low-order corner, the positive frequency terms in the + first half of all axes, the term for the Nyquist frequency in the middle + of all axes and the negative frequency terms in the second half of all + axes, in order of decreasingly negative frequency. + + Parameters + ---------- + a : array_like + Input array, can be complex. + s : sequence of ints, optional + Shape (length of each transformed axis) of the output + (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.). + This corresponds to ``n`` for ``ifft(x, n)``. + Along any axis, if the given shape is smaller than that of the input, + the input is cropped. If it is larger, the input is padded with zeros. + if `s` is not given, the shape of the input along the axes specified + by `axes` is used. See notes for issue on `ifft` zero padding. + axes : sequence of ints, optional + Axes over which to compute the IFFT. If not given, the last ``len(s)`` + axes are used, or all axes if `s` is also not specified. + Repeated indices in `axes` means that the inverse transform over that + axis is performed multiple times. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : complex ndarray + The truncated or zero-padded input, transformed along the axes + indicated by `axes`, or by a combination of `s` or `a`, + as explained in the parameters section above. + + Raises + ------ + ValueError + If `s` and `axes` have different length. + IndexError + If an element of `axes` is larger than than the number of axes of `a`. + + See Also + -------- + numpy.fft : Overall view of discrete Fourier transforms, with definitions + and conventions used. + fftn : The forward *n*-dimensional FFT, of which `ifftn` is the inverse. + ifft : The one-dimensional inverse FFT. + ifft2 : The two-dimensional inverse FFT. + ifftshift : Undoes `fftshift`, shifts zero-frequency terms to beginning + of array. + + Notes + ----- + See `numpy.fft` for definitions and conventions used. + + Zero-padding, analogously with `ifft`, is performed by appending zeros to + the input along the specified dimension. Although this is the common + approach, it might lead to surprising results. If another form of zero + padding is desired, it must be performed before `ifftn` is called. + + Examples + -------- + >>> a = np.eye(4) + >>> np.fft.ifftn(np.fft.fftn(a, axes=(0,)), axes=(1,)) + array([[1.+0.j, 0.+0.j, 0.+0.j, 0.+0.j], # may vary + [0.+0.j, 1.+0.j, 0.+0.j, 0.+0.j], + [0.+0.j, 0.+0.j, 1.+0.j, 0.+0.j], + [0.+0.j, 0.+0.j, 0.+0.j, 1.+0.j]]) + + + Create and plot an image with band-limited frequency content: + + >>> import matplotlib.pyplot as plt + >>> n = np.zeros((200,200), dtype=complex) + >>> n[60:80, 20:40] = np.exp(1j*np.random.uniform(0, 2*np.pi, (20, 20))) + >>> im = np.fft.ifftn(n).real + >>> plt.imshow(im) + <matplotlib.image.AxesImage object at 0x...> + >>> plt.show() + + """ + return _raw_fftnd(a, s, axes, ifft, norm) + + +@array_function_dispatch(_fftn_dispatcher) +def fft2(a, s=None, axes=(-2, -1), norm=None): + """ + Compute the 2-dimensional discrete Fourier Transform. + + This function computes the *n*-dimensional discrete Fourier Transform + over any axes in an *M*-dimensional array by means of the + Fast Fourier Transform (FFT). By default, the transform is computed over + the last two axes of the input array, i.e., a 2-dimensional FFT. + + Parameters + ---------- + a : array_like + Input array, can be complex + s : sequence of ints, optional + Shape (length of each transformed axis) of the output + (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.). + This corresponds to ``n`` for ``fft(x, n)``. + Along each axis, if the given shape is smaller than that of the input, + the input is cropped. If it is larger, the input is padded with zeros. + if `s` is not given, the shape of the input along the axes specified + by `axes` is used. + axes : sequence of ints, optional + Axes over which to compute the FFT. If not given, the last two + axes are used. A repeated index in `axes` means the transform over + that axis is performed multiple times. A one-element sequence means + that a one-dimensional FFT is performed. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : complex ndarray + The truncated or zero-padded input, transformed along the axes + indicated by `axes`, or the last two axes if `axes` is not given. + + Raises + ------ + ValueError + If `s` and `axes` have different length, or `axes` not given and + ``len(s) != 2``. + IndexError + If an element of `axes` is larger than than the number of axes of `a`. + + See Also + -------- + numpy.fft : Overall view of discrete Fourier transforms, with definitions + and conventions used. + ifft2 : The inverse two-dimensional FFT. + fft : The one-dimensional FFT. + fftn : The *n*-dimensional FFT. + fftshift : Shifts zero-frequency terms to the center of the array. + For two-dimensional input, swaps first and third quadrants, and second + and fourth quadrants. + + Notes + ----- + `fft2` is just `fftn` with a different default for `axes`. + + The output, analogously to `fft`, contains the term for zero frequency in + the low-order corner of the transformed axes, the positive frequency terms + in the first half of these axes, the term for the Nyquist frequency in the + middle of the axes and the negative frequency terms in the second half of + the axes, in order of decreasingly negative frequency. + + See `fftn` for details and a plotting example, and `numpy.fft` for + definitions and conventions used. + + + Examples + -------- + >>> a = np.mgrid[:5, :5][0] + >>> np.fft.fft2(a) + array([[ 50. +0.j , 0. +0.j , 0. +0.j , # may vary + 0. +0.j , 0. +0.j ], + [-12.5+17.20477401j, 0. +0.j , 0. +0.j , + 0. +0.j , 0. +0.j ], + [-12.5 +4.0614962j , 0. +0.j , 0. +0.j , + 0. +0.j , 0. +0.j ], + [-12.5 -4.0614962j , 0. +0.j , 0. +0.j , + 0. +0.j , 0. +0.j ], + [-12.5-17.20477401j, 0. +0.j , 0. +0.j , + 0. +0.j , 0. +0.j ]]) + + """ + return _raw_fftnd(a, s, axes, fft, norm) + + +@array_function_dispatch(_fftn_dispatcher) +def ifft2(a, s=None, axes=(-2, -1), norm=None): + """ + Compute the 2-dimensional inverse discrete Fourier Transform. + + This function computes the inverse of the 2-dimensional discrete Fourier + Transform over any number of axes in an M-dimensional array by means of + the Fast Fourier Transform (FFT). In other words, ``ifft2(fft2(a)) == a`` + to within numerical accuracy. By default, the inverse transform is + computed over the last two axes of the input array. + + The input, analogously to `ifft`, should be ordered in the same way as is + returned by `fft2`, i.e. it should have the term for zero frequency + in the low-order corner of the two axes, the positive frequency terms in + the first half of these axes, the term for the Nyquist frequency in the + middle of the axes and the negative frequency terms in the second half of + both axes, in order of decreasingly negative frequency. + + Parameters + ---------- + a : array_like + Input array, can be complex. + s : sequence of ints, optional + Shape (length of each axis) of the output (``s[0]`` refers to axis 0, + ``s[1]`` to axis 1, etc.). This corresponds to `n` for ``ifft(x, n)``. + Along each axis, if the given shape is smaller than that of the input, + the input is cropped. If it is larger, the input is padded with zeros. + if `s` is not given, the shape of the input along the axes specified + by `axes` is used. See notes for issue on `ifft` zero padding. + axes : sequence of ints, optional + Axes over which to compute the FFT. If not given, the last two + axes are used. A repeated index in `axes` means the transform over + that axis is performed multiple times. A one-element sequence means + that a one-dimensional FFT is performed. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : complex ndarray + The truncated or zero-padded input, transformed along the axes + indicated by `axes`, or the last two axes if `axes` is not given. + + Raises + ------ + ValueError + If `s` and `axes` have different length, or `axes` not given and + ``len(s) != 2``. + IndexError + If an element of `axes` is larger than than the number of axes of `a`. + + See Also + -------- + numpy.fft : Overall view of discrete Fourier transforms, with definitions + and conventions used. + fft2 : The forward 2-dimensional FFT, of which `ifft2` is the inverse. + ifftn : The inverse of the *n*-dimensional FFT. + fft : The one-dimensional FFT. + ifft : The one-dimensional inverse FFT. + + Notes + ----- + `ifft2` is just `ifftn` with a different default for `axes`. + + See `ifftn` for details and a plotting example, and `numpy.fft` for + definition and conventions used. + + Zero-padding, analogously with `ifft`, is performed by appending zeros to + the input along the specified dimension. Although this is the common + approach, it might lead to surprising results. If another form of zero + padding is desired, it must be performed before `ifft2` is called. + + Examples + -------- + >>> a = 4 * np.eye(4) + >>> np.fft.ifft2(a) + array([[1.+0.j, 0.+0.j, 0.+0.j, 0.+0.j], # may vary + [0.+0.j, 0.+0.j, 0.+0.j, 1.+0.j], + [0.+0.j, 0.+0.j, 1.+0.j, 0.+0.j], + [0.+0.j, 1.+0.j, 0.+0.j, 0.+0.j]]) + + """ + return _raw_fftnd(a, s, axes, ifft, norm) + + +@array_function_dispatch(_fftn_dispatcher) +def rfftn(a, s=None, axes=None, norm=None): + """ + Compute the N-dimensional discrete Fourier Transform for real input. + + This function computes the N-dimensional discrete Fourier Transform over + any number of axes in an M-dimensional real array by means of the Fast + Fourier Transform (FFT). By default, all axes are transformed, with the + real transform performed over the last axis, while the remaining + transforms are complex. + + Parameters + ---------- + a : array_like + Input array, taken to be real. + s : sequence of ints, optional + Shape (length along each transformed axis) to use from the input. + (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.). + The final element of `s` corresponds to `n` for ``rfft(x, n)``, while + for the remaining axes, it corresponds to `n` for ``fft(x, n)``. + Along any axis, if the given shape is smaller than that of the input, + the input is cropped. If it is larger, the input is padded with zeros. + if `s` is not given, the shape of the input along the axes specified + by `axes` is used. + axes : sequence of ints, optional + Axes over which to compute the FFT. If not given, the last ``len(s)`` + axes are used, or all axes if `s` is also not specified. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : complex ndarray + The truncated or zero-padded input, transformed along the axes + indicated by `axes`, or by a combination of `s` and `a`, + as explained in the parameters section above. + The length of the last axis transformed will be ``s[-1]//2+1``, + while the remaining transformed axes will have lengths according to + `s`, or unchanged from the input. + + Raises + ------ + ValueError + If `s` and `axes` have different length. + IndexError + If an element of `axes` is larger than than the number of axes of `a`. + + See Also + -------- + irfftn : The inverse of `rfftn`, i.e. the inverse of the n-dimensional FFT + of real input. + fft : The one-dimensional FFT, with definitions and conventions used. + rfft : The one-dimensional FFT of real input. + fftn : The n-dimensional FFT. + rfft2 : The two-dimensional FFT of real input. + + Notes + ----- + The transform for real input is performed over the last transformation + axis, as by `rfft`, then the transform over the remaining axes is + performed as by `fftn`. The order of the output is as for `rfft` for the + final transformation axis, and as for `fftn` for the remaining + transformation axes. + + See `fft` for details, definitions and conventions used. + + Examples + -------- + >>> a = np.ones((2, 2, 2)) + >>> np.fft.rfftn(a) + array([[[8.+0.j, 0.+0.j], # may vary + [0.+0.j, 0.+0.j]], + [[0.+0.j, 0.+0.j], + [0.+0.j, 0.+0.j]]]) + + >>> np.fft.rfftn(a, axes=(2, 0)) + array([[[4.+0.j, 0.+0.j], # may vary + [4.+0.j, 0.+0.j]], + [[0.+0.j, 0.+0.j], + [0.+0.j, 0.+0.j]]]) + + """ + a = asarray(a) + s, axes = _cook_nd_args(a, s, axes) + a = rfft(a, s[-1], axes[-1], norm) + for ii in range(len(axes)-1): + a = fft(a, s[ii], axes[ii], norm) + return a + + +@array_function_dispatch(_fftn_dispatcher) +def rfft2(a, s=None, axes=(-2, -1), norm=None): + """ + Compute the 2-dimensional FFT of a real array. + + Parameters + ---------- + a : array + Input array, taken to be real. + s : sequence of ints, optional + Shape of the FFT. + axes : sequence of ints, optional + Axes over which to compute the FFT. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : ndarray + The result of the real 2-D FFT. + + See Also + -------- + rfftn : Compute the N-dimensional discrete Fourier Transform for real + input. + + Notes + ----- + This is really just `rfftn` with different default behavior. + For more details see `rfftn`. + + Examples + -------- + >>> a = np.mgrid[:5, :5][0] + >>> np.fft.rfft2(a) + array([[ 50. +0.j , 0. +0.j , 0. +0.j ], + [-12.5+17.20477401j, 0. +0.j , 0. +0.j ], + [-12.5 +4.0614962j , 0. +0.j , 0. +0.j ], + [-12.5 -4.0614962j , 0. +0.j , 0. +0.j ], + [-12.5-17.20477401j, 0. +0.j , 0. +0.j ]]) + """ + return rfftn(a, s, axes, norm) + + +@array_function_dispatch(_fftn_dispatcher) +def irfftn(a, s=None, axes=None, norm=None): + """ + Computes the inverse of `rfftn`. + + This function computes the inverse of the N-dimensional discrete + Fourier Transform for real input over any number of axes in an + M-dimensional array by means of the Fast Fourier Transform (FFT). In + other words, ``irfftn(rfftn(a), a.shape) == a`` to within numerical + accuracy. (The ``a.shape`` is necessary like ``len(a)`` is for `irfft`, + and for the same reason.) + + The input should be ordered in the same way as is returned by `rfftn`, + i.e. as for `irfft` for the final transformation axis, and as for `ifftn` + along all the other axes. + + Parameters + ---------- + a : array_like + Input array. + s : sequence of ints, optional + Shape (length of each transformed axis) of the output + (``s[0]`` refers to axis 0, ``s[1]`` to axis 1, etc.). `s` is also the + number of input points used along this axis, except for the last axis, + where ``s[-1]//2+1`` points of the input are used. + Along any axis, if the shape indicated by `s` is smaller than that of + the input, the input is cropped. If it is larger, the input is padded + with zeros. If `s` is not given, the shape of the input along the axes + specified by axes is used. Except for the last axis which is taken to + be ``2*(m-1)`` where ``m`` is the length of the input along that axis. + axes : sequence of ints, optional + Axes over which to compute the inverse FFT. If not given, the last + `len(s)` axes are used, or all axes if `s` is also not specified. + Repeated indices in `axes` means that the inverse transform over that + axis is performed multiple times. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : ndarray + The truncated or zero-padded input, transformed along the axes + indicated by `axes`, or by a combination of `s` or `a`, + as explained in the parameters section above. + The length of each transformed axis is as given by the corresponding + element of `s`, or the length of the input in every axis except for the + last one if `s` is not given. In the final transformed axis the length + of the output when `s` is not given is ``2*(m-1)`` where ``m`` is the + length of the final transformed axis of the input. To get an odd + number of output points in the final axis, `s` must be specified. + + Raises + ------ + ValueError + If `s` and `axes` have different length. + IndexError + If an element of `axes` is larger than than the number of axes of `a`. + + See Also + -------- + rfftn : The forward n-dimensional FFT of real input, + of which `ifftn` is the inverse. + fft : The one-dimensional FFT, with definitions and conventions used. + irfft : The inverse of the one-dimensional FFT of real input. + irfft2 : The inverse of the two-dimensional FFT of real input. + + Notes + ----- + See `fft` for definitions and conventions used. + + See `rfft` for definitions and conventions used for real input. + + The correct interpretation of the hermitian input depends on the shape of + the original data, as given by `s`. This is because each input shape could + correspond to either an odd or even length signal. By default, `irfftn` + assumes an even output length which puts the last entry at the Nyquist + frequency; aliasing with its symmetric counterpart. When performing the + final complex to real transform, the last value is thus treated as purely + real. To avoid losing information, the correct shape of the real input + **must** be given. + + Examples + -------- + >>> a = np.zeros((3, 2, 2)) + >>> a[0, 0, 0] = 3 * 2 * 2 + >>> np.fft.irfftn(a) + array([[[1., 1.], + [1., 1.]], + [[1., 1.], + [1., 1.]], + [[1., 1.], + [1., 1.]]]) + + """ + a = asarray(a) + s, axes = _cook_nd_args(a, s, axes, invreal=1) + for ii in range(len(axes)-1): + a = ifft(a, s[ii], axes[ii], norm) + a = irfft(a, s[-1], axes[-1], norm) + return a + + +@array_function_dispatch(_fftn_dispatcher) +def irfft2(a, s=None, axes=(-2, -1), norm=None): + """ + Computes the inverse of `rfft2`. + + Parameters + ---------- + a : array_like + The input array + s : sequence of ints, optional + Shape of the real output to the inverse FFT. + axes : sequence of ints, optional + The axes over which to compute the inverse fft. + Default is the last two axes. + norm : {"backward", "ortho", "forward"}, optional + .. versionadded:: 1.10.0 + + Normalization mode (see `numpy.fft`). Default is "backward". + Indicates which direction of the forward/backward pair of transforms + is scaled and with what normalization factor. + + .. versionadded:: 1.20.0 + + The "backward", "forward" values were added. + + Returns + ------- + out : ndarray + The result of the inverse real 2-D FFT. + + See Also + -------- + rfft2 : The forward two-dimensional FFT of real input, + of which `irfft2` is the inverse. + rfft : The one-dimensional FFT for real input. + irfft : The inverse of the one-dimensional FFT of real input. + irfftn : Compute the inverse of the N-dimensional FFT of real input. + + Notes + ----- + This is really `irfftn` with different defaults. + For more details see `irfftn`. + + Examples + -------- + >>> a = np.mgrid[:5, :5][0] + >>> A = np.fft.rfft2(a) + >>> np.fft.irfft2(A, s=a.shape) + 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.]]) + """ + return irfftn(a, s, axes, norm) diff --git a/.venv/lib/python3.12/site-packages/numpy/fft/_pocketfft.pyi b/.venv/lib/python3.12/site-packages/numpy/fft/_pocketfft.pyi new file mode 100644 index 00000000..2bd8b0ba --- /dev/null +++ b/.venv/lib/python3.12/site-packages/numpy/fft/_pocketfft.pyi @@ -0,0 +1,108 @@ +from collections.abc import Sequence +from typing import Literal as L + +from numpy import complex128, float64 +from numpy._typing import ArrayLike, NDArray, _ArrayLikeNumber_co + +_NormKind = L[None, "backward", "ortho", "forward"] + +__all__: list[str] + +def fft( + a: ArrayLike, + n: None | int = ..., + axis: int = ..., + norm: _NormKind = ..., +) -> NDArray[complex128]: ... + +def ifft( + a: ArrayLike, + n: None | int = ..., + axis: int = ..., + norm: _NormKind = ..., +) -> NDArray[complex128]: ... + +def rfft( + a: ArrayLike, + n: None | int = ..., + axis: int = ..., + norm: _NormKind = ..., +) -> NDArray[complex128]: ... + +def irfft( + a: ArrayLike, + n: None | int = ..., + axis: int = ..., + norm: _NormKind = ..., +) -> NDArray[float64]: ... + +# Input array must be compatible with `np.conjugate` +def hfft( + a: _ArrayLikeNumber_co, + n: None | int = ..., + axis: int = ..., + norm: _NormKind = ..., +) -> NDArray[float64]: ... + +def ihfft( + a: ArrayLike, + n: None | int = ..., + axis: int = ..., + norm: _NormKind = ..., +) -> NDArray[complex128]: ... + +def fftn( + a: ArrayLike, + s: None | Sequence[int] = ..., + axes: None | Sequence[int] = ..., + norm: _NormKind = ..., +) -> NDArray[complex128]: ... + +def ifftn( + a: ArrayLike, + s: None | Sequence[int] = ..., + axes: None | Sequence[int] = ..., + norm: _NormKind = ..., +) -> NDArray[complex128]: ... + +def rfftn( + a: ArrayLike, + s: None | Sequence[int] = ..., + axes: None | Sequence[int] = ..., + norm: _NormKind = ..., +) -> NDArray[complex128]: ... + +def irfftn( + a: ArrayLike, + s: None | Sequence[int] = ..., + axes: None | Sequence[int] = ..., + norm: _NormKind = ..., +) -> NDArray[float64]: ... + +def fft2( + a: ArrayLike, + s: None | Sequence[int] = ..., + axes: None | Sequence[int] = ..., + norm: _NormKind = ..., +) -> NDArray[complex128]: ... + +def ifft2( + a: ArrayLike, + s: None | Sequence[int] = ..., + axes: None | Sequence[int] = ..., + norm: _NormKind = ..., +) -> NDArray[complex128]: ... + +def rfft2( + a: ArrayLike, + s: None | Sequence[int] = ..., + axes: None | Sequence[int] = ..., + norm: _NormKind = ..., +) -> NDArray[complex128]: ... + +def irfft2( + a: ArrayLike, + s: None | Sequence[int] = ..., + axes: None | Sequence[int] = ..., + norm: _NormKind = ..., +) -> NDArray[float64]: ... diff --git a/.venv/lib/python3.12/site-packages/numpy/fft/_pocketfft_internal.cpython-312-x86_64-linux-gnu.so b/.venv/lib/python3.12/site-packages/numpy/fft/_pocketfft_internal.cpython-312-x86_64-linux-gnu.so Binary files differnew file mode 100755 index 00000000..87cc095a --- /dev/null +++ b/.venv/lib/python3.12/site-packages/numpy/fft/_pocketfft_internal.cpython-312-x86_64-linux-gnu.so diff --git a/.venv/lib/python3.12/site-packages/numpy/fft/helper.py b/.venv/lib/python3.12/site-packages/numpy/fft/helper.py new file mode 100644 index 00000000..927ee1af --- /dev/null +++ b/.venv/lib/python3.12/site-packages/numpy/fft/helper.py @@ -0,0 +1,221 @@ +""" +Discrete Fourier Transforms - helper.py + +""" +from numpy.core import integer, empty, arange, asarray, roll +from numpy.core.overrides import array_function_dispatch, set_module + +# Created by Pearu Peterson, September 2002 + +__all__ = ['fftshift', 'ifftshift', 'fftfreq', 'rfftfreq'] + +integer_types = (int, integer) + + +def _fftshift_dispatcher(x, axes=None): + return (x,) + + +@array_function_dispatch(_fftshift_dispatcher, module='numpy.fft') +def fftshift(x, axes=None): + """ + Shift the zero-frequency component to the center of the spectrum. + + This function swaps half-spaces for all axes listed (defaults to all). + Note that ``y[0]`` is the Nyquist component only if ``len(x)`` is even. + + Parameters + ---------- + x : array_like + Input array. + axes : int or shape tuple, optional + Axes over which to shift. Default is None, which shifts all axes. + + Returns + ------- + y : ndarray + The shifted array. + + See Also + -------- + ifftshift : The inverse of `fftshift`. + + Examples + -------- + >>> freqs = np.fft.fftfreq(10, 0.1) + >>> freqs + array([ 0., 1., 2., ..., -3., -2., -1.]) + >>> np.fft.fftshift(freqs) + array([-5., -4., -3., -2., -1., 0., 1., 2., 3., 4.]) + + Shift the zero-frequency component only along the second axis: + + >>> freqs = np.fft.fftfreq(9, d=1./9).reshape(3, 3) + >>> freqs + array([[ 0., 1., 2.], + [ 3., 4., -4.], + [-3., -2., -1.]]) + >>> np.fft.fftshift(freqs, axes=(1,)) + array([[ 2., 0., 1.], + [-4., 3., 4.], + [-1., -3., -2.]]) + + """ + x = asarray(x) + if axes is None: + axes = tuple(range(x.ndim)) + shift = [dim // 2 for dim in x.shape] + elif isinstance(axes, integer_types): + shift = x.shape[axes] // 2 + else: + shift = [x.shape[ax] // 2 for ax in axes] + + return roll(x, shift, axes) + + +@array_function_dispatch(_fftshift_dispatcher, module='numpy.fft') +def ifftshift(x, axes=None): + """ + The inverse of `fftshift`. Although identical for even-length `x`, the + functions differ by one sample for odd-length `x`. + + Parameters + ---------- + x : array_like + Input array. + axes : int or shape tuple, optional + Axes over which to calculate. Defaults to None, which shifts all axes. + + Returns + ------- + y : ndarray + The shifted array. + + See Also + -------- + fftshift : Shift zero-frequency component to the center of the spectrum. + + Examples + -------- + >>> freqs = np.fft.fftfreq(9, d=1./9).reshape(3, 3) + >>> freqs + array([[ 0., 1., 2.], + [ 3., 4., -4.], + [-3., -2., -1.]]) + >>> np.fft.ifftshift(np.fft.fftshift(freqs)) + array([[ 0., 1., 2.], + [ 3., 4., -4.], + [-3., -2., -1.]]) + + """ + x = asarray(x) + if axes is None: + axes = tuple(range(x.ndim)) + shift = [-(dim // 2) for dim in x.shape] + elif isinstance(axes, integer_types): + shift = -(x.shape[axes] // 2) + else: + shift = [-(x.shape[ax] // 2) for ax in axes] + + return roll(x, shift, axes) + + +@set_module('numpy.fft') +def fftfreq(n, d=1.0): + """ + Return the Discrete Fourier Transform sample frequencies. + + The returned float array `f` contains the frequency bin centers in cycles + per unit of the sample spacing (with zero at the start). For instance, if + the sample spacing is in seconds, then the frequency unit is cycles/second. + + Given a window length `n` and a sample spacing `d`:: + + f = [0, 1, ..., n/2-1, -n/2, ..., -1] / (d*n) if n is even + f = [0, 1, ..., (n-1)/2, -(n-1)/2, ..., -1] / (d*n) if n is odd + + Parameters + ---------- + n : int + Window length. + d : scalar, optional + Sample spacing (inverse of the sampling rate). Defaults to 1. + + Returns + ------- + f : ndarray + Array of length `n` containing the sample frequencies. + + Examples + -------- + >>> signal = np.array([-2, 8, 6, 4, 1, 0, 3, 5], dtype=float) + >>> fourier = np.fft.fft(signal) + >>> n = signal.size + >>> timestep = 0.1 + >>> freq = np.fft.fftfreq(n, d=timestep) + >>> freq + array([ 0. , 1.25, 2.5 , ..., -3.75, -2.5 , -1.25]) + + """ + if not isinstance(n, integer_types): + raise ValueError("n should be an integer") + val = 1.0 / (n * d) + results = empty(n, int) + N = (n-1)//2 + 1 + p1 = arange(0, N, dtype=int) + results[:N] = p1 + p2 = arange(-(n//2), 0, dtype=int) + results[N:] = p2 + return results * val + + +@set_module('numpy.fft') +def rfftfreq(n, d=1.0): + """ + Return the Discrete Fourier Transform sample frequencies + (for usage with rfft, irfft). + + The returned float array `f` contains the frequency bin centers in cycles + per unit of the sample spacing (with zero at the start). For instance, if + the sample spacing is in seconds, then the frequency unit is cycles/second. + + Given a window length `n` and a sample spacing `d`:: + + f = [0, 1, ..., n/2-1, n/2] / (d*n) if n is even + f = [0, 1, ..., (n-1)/2-1, (n-1)/2] / (d*n) if n is odd + + Unlike `fftfreq` (but like `scipy.fftpack.rfftfreq`) + the Nyquist frequency component is considered to be positive. + + Parameters + ---------- + n : int + Window length. + d : scalar, optional + Sample spacing (inverse of the sampling rate). Defaults to 1. + + Returns + ------- + f : ndarray + Array of length ``n//2 + 1`` containing the sample frequencies. + + Examples + -------- + >>> signal = np.array([-2, 8, 6, 4, 1, 0, 3, 5, -3, 4], dtype=float) + >>> fourier = np.fft.rfft(signal) + >>> n = signal.size + >>> sample_rate = 100 + >>> freq = np.fft.fftfreq(n, d=1./sample_rate) + >>> freq + array([ 0., 10., 20., ..., -30., -20., -10.]) + >>> freq = np.fft.rfftfreq(n, d=1./sample_rate) + >>> freq + array([ 0., 10., 20., 30., 40., 50.]) + + """ + if not isinstance(n, integer_types): + raise ValueError("n should be an integer") + val = 1.0/(n*d) + N = n//2 + 1 + results = arange(0, N, dtype=int) + return results * val diff --git a/.venv/lib/python3.12/site-packages/numpy/fft/helper.pyi b/.venv/lib/python3.12/site-packages/numpy/fft/helper.pyi new file mode 100644 index 00000000..9b652519 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/numpy/fft/helper.pyi @@ -0,0 +1,47 @@ +from typing import Any, TypeVar, overload + +from numpy import generic, integer, floating, complexfloating +from numpy._typing import ( + NDArray, + ArrayLike, + _ShapeLike, + _ArrayLike, + _ArrayLikeFloat_co, + _ArrayLikeComplex_co, +) + +_SCT = TypeVar("_SCT", bound=generic) + +__all__: list[str] + +@overload +def fftshift(x: _ArrayLike[_SCT], axes: None | _ShapeLike = ...) -> NDArray[_SCT]: ... +@overload +def fftshift(x: ArrayLike, axes: None | _ShapeLike = ...) -> NDArray[Any]: ... + +@overload +def ifftshift(x: _ArrayLike[_SCT], axes: None | _ShapeLike = ...) -> NDArray[_SCT]: ... +@overload +def ifftshift(x: ArrayLike, axes: None | _ShapeLike = ...) -> NDArray[Any]: ... + +@overload +def fftfreq( + n: int | integer[Any], + d: _ArrayLikeFloat_co = ..., +) -> NDArray[floating[Any]]: ... +@overload +def fftfreq( + n: int | integer[Any], + d: _ArrayLikeComplex_co = ..., +) -> NDArray[complexfloating[Any, Any]]: ... + +@overload +def rfftfreq( + n: int | integer[Any], + d: _ArrayLikeFloat_co = ..., +) -> NDArray[floating[Any]]: ... +@overload +def rfftfreq( + n: int | integer[Any], + d: _ArrayLikeComplex_co = ..., +) -> NDArray[complexfloating[Any, Any]]: ... diff --git a/.venv/lib/python3.12/site-packages/numpy/fft/tests/__init__.py b/.venv/lib/python3.12/site-packages/numpy/fft/tests/__init__.py new file mode 100644 index 00000000..e69de29b --- /dev/null +++ b/.venv/lib/python3.12/site-packages/numpy/fft/tests/__init__.py diff --git a/.venv/lib/python3.12/site-packages/numpy/fft/tests/test_helper.py b/.venv/lib/python3.12/site-packages/numpy/fft/tests/test_helper.py new file mode 100644 index 00000000..3fb700bb --- /dev/null +++ b/.venv/lib/python3.12/site-packages/numpy/fft/tests/test_helper.py @@ -0,0 +1,167 @@ +"""Test functions for fftpack.helper module + +Copied from fftpack.helper by Pearu Peterson, October 2005 + +""" +import numpy as np +from numpy.testing import assert_array_almost_equal +from numpy import fft, pi + + +class TestFFTShift: + + 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(fft.fftshift(x), y) + assert_array_almost_equal(fft.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(fft.fftshift(x), y) + assert_array_almost_equal(fft.ifftshift(y), x) + + def test_inverse(self): + for n in [1, 4, 9, 100, 211]: + x = np.random.random((n,)) + assert_array_almost_equal(fft.ifftshift(fft.fftshift(x)), x) + + def test_axes_keyword(self): + freqs = [[0, 1, 2], [3, 4, -4], [-3, -2, -1]] + shifted = [[-1, -3, -2], [2, 0, 1], [-4, 3, 4]] + assert_array_almost_equal(fft.fftshift(freqs, axes=(0, 1)), shifted) + assert_array_almost_equal(fft.fftshift(freqs, axes=0), + fft.fftshift(freqs, axes=(0,))) + assert_array_almost_equal(fft.ifftshift(shifted, axes=(0, 1)), freqs) + assert_array_almost_equal(fft.ifftshift(shifted, axes=0), + fft.ifftshift(shifted, axes=(0,))) + + assert_array_almost_equal(fft.fftshift(freqs), shifted) + assert_array_almost_equal(fft.ifftshift(shifted), freqs) + + def test_uneven_dims(self): + """ Test 2D input, which has uneven dimension sizes """ + freqs = [ + [0, 1], + [2, 3], + [4, 5] + ] + + # shift in dimension 0 + shift_dim0 = [ + [4, 5], + [0, 1], + [2, 3] + ] + assert_array_almost_equal(fft.fftshift(freqs, axes=0), shift_dim0) + assert_array_almost_equal(fft.ifftshift(shift_dim0, axes=0), freqs) + assert_array_almost_equal(fft.fftshift(freqs, axes=(0,)), shift_dim0) + assert_array_almost_equal(fft.ifftshift(shift_dim0, axes=[0]), freqs) + + # shift in dimension 1 + shift_dim1 = [ + [1, 0], + [3, 2], + [5, 4] + ] + assert_array_almost_equal(fft.fftshift(freqs, axes=1), shift_dim1) + assert_array_almost_equal(fft.ifftshift(shift_dim1, axes=1), freqs) + + # shift in both dimensions + shift_dim_both = [ + [5, 4], + [1, 0], + [3, 2] + ] + assert_array_almost_equal(fft.fftshift(freqs, axes=(0, 1)), shift_dim_both) + assert_array_almost_equal(fft.ifftshift(shift_dim_both, axes=(0, 1)), freqs) + assert_array_almost_equal(fft.fftshift(freqs, axes=[0, 1]), shift_dim_both) + assert_array_almost_equal(fft.ifftshift(shift_dim_both, axes=[0, 1]), freqs) + + # axes=None (default) shift in all dimensions + assert_array_almost_equal(fft.fftshift(freqs, axes=None), shift_dim_both) + assert_array_almost_equal(fft.ifftshift(shift_dim_both, axes=None), freqs) + assert_array_almost_equal(fft.fftshift(freqs), shift_dim_both) + assert_array_almost_equal(fft.ifftshift(shift_dim_both), freqs) + + def test_equal_to_original(self): + """ Test that the new (>=v1.15) implementation (see #10073) is equal to the original (<=v1.14) """ + from numpy.core import asarray, concatenate, arange, take + + def original_fftshift(x, axes=None): + """ How fftshift was implemented in v1.14""" + tmp = asarray(x) + ndim = tmp.ndim + if axes is None: + axes = list(range(ndim)) + elif isinstance(axes, int): + axes = (axes,) + y = tmp + for k in axes: + n = tmp.shape[k] + p2 = (n + 1) // 2 + mylist = concatenate((arange(p2, n), arange(p2))) + y = take(y, mylist, k) + return y + + def original_ifftshift(x, axes=None): + """ How ifftshift was implemented in v1.14 """ + tmp = asarray(x) + ndim = tmp.ndim + if axes is None: + axes = list(range(ndim)) + elif isinstance(axes, int): + axes = (axes,) + y = tmp + for k in axes: + n = tmp.shape[k] + p2 = n - (n + 1) // 2 + mylist = concatenate((arange(p2, n), arange(p2))) + y = take(y, mylist, k) + return y + + # create possible 2d array combinations and try all possible keywords + # compare output to original functions + for i in range(16): + for j in range(16): + for axes_keyword in [0, 1, None, (0,), (0, 1)]: + inp = np.random.rand(i, j) + + assert_array_almost_equal(fft.fftshift(inp, axes_keyword), + original_fftshift(inp, axes_keyword)) + + assert_array_almost_equal(fft.ifftshift(inp, axes_keyword), + original_ifftshift(inp, axes_keyword)) + + +class TestFFTFreq: + + def test_definition(self): + x = [0, 1, 2, 3, 4, -4, -3, -2, -1] + assert_array_almost_equal(9*fft.fftfreq(9), x) + assert_array_almost_equal(9*pi*fft.fftfreq(9, pi), x) + x = [0, 1, 2, 3, 4, -5, -4, -3, -2, -1] + assert_array_almost_equal(10*fft.fftfreq(10), x) + assert_array_almost_equal(10*pi*fft.fftfreq(10, pi), x) + + +class TestRFFTFreq: + + def test_definition(self): + x = [0, 1, 2, 3, 4] + assert_array_almost_equal(9*fft.rfftfreq(9), x) + assert_array_almost_equal(9*pi*fft.rfftfreq(9, pi), x) + x = [0, 1, 2, 3, 4, 5] + assert_array_almost_equal(10*fft.rfftfreq(10), x) + assert_array_almost_equal(10*pi*fft.rfftfreq(10, pi), x) + + +class TestIRFFTN: + + def test_not_last_axis_success(self): + ar, ai = np.random.random((2, 16, 8, 32)) + a = ar + 1j*ai + + axes = (-2,) + + # Should not raise error + fft.irfftn(a, axes=axes) diff --git a/.venv/lib/python3.12/site-packages/numpy/fft/tests/test_pocketfft.py b/.venv/lib/python3.12/site-packages/numpy/fft/tests/test_pocketfft.py new file mode 100644 index 00000000..122a9fac --- /dev/null +++ b/.venv/lib/python3.12/site-packages/numpy/fft/tests/test_pocketfft.py @@ -0,0 +1,308 @@ +import numpy as np +import pytest +from numpy.random import random +from numpy.testing import ( + assert_array_equal, assert_raises, assert_allclose, IS_WASM + ) +import threading +import queue + + +def fft1(x): + L = len(x) + phase = -2j * np.pi * (np.arange(L) / L) + phase = np.arange(L).reshape(-1, 1) * phase + return np.sum(x*np.exp(phase), axis=1) + + +class TestFFTShift: + + def test_fft_n(self): + assert_raises(ValueError, np.fft.fft, [1, 2, 3], 0) + + +class TestFFT1D: + + def test_identity(self): + maxlen = 512 + x = random(maxlen) + 1j*random(maxlen) + xr = random(maxlen) + for i in range(1, maxlen): + assert_allclose(np.fft.ifft(np.fft.fft(x[0:i])), x[0:i], + atol=1e-12) + assert_allclose(np.fft.irfft(np.fft.rfft(xr[0:i]), i), + xr[0:i], atol=1e-12) + + def test_fft(self): + x = random(30) + 1j*random(30) + assert_allclose(fft1(x), np.fft.fft(x), atol=1e-6) + assert_allclose(fft1(x), np.fft.fft(x, norm="backward"), atol=1e-6) + assert_allclose(fft1(x) / np.sqrt(30), + np.fft.fft(x, norm="ortho"), atol=1e-6) + assert_allclose(fft1(x) / 30., + np.fft.fft(x, norm="forward"), atol=1e-6) + + @pytest.mark.parametrize('norm', (None, 'backward', 'ortho', 'forward')) + def test_ifft(self, norm): + x = random(30) + 1j*random(30) + assert_allclose( + x, np.fft.ifft(np.fft.fft(x, norm=norm), norm=norm), + atol=1e-6) + # Ensure we get the correct error message + with pytest.raises(ValueError, + match='Invalid number of FFT data points'): + np.fft.ifft([], norm=norm) + + def test_fft2(self): + x = random((30, 20)) + 1j*random((30, 20)) + assert_allclose(np.fft.fft(np.fft.fft(x, axis=1), axis=0), + np.fft.fft2(x), atol=1e-6) + assert_allclose(np.fft.fft2(x), + np.fft.fft2(x, norm="backward"), atol=1e-6) + assert_allclose(np.fft.fft2(x) / np.sqrt(30 * 20), + np.fft.fft2(x, norm="ortho"), atol=1e-6) + assert_allclose(np.fft.fft2(x) / (30. * 20.), + np.fft.fft2(x, norm="forward"), atol=1e-6) + + def test_ifft2(self): + x = random((30, 20)) + 1j*random((30, 20)) + assert_allclose(np.fft.ifft(np.fft.ifft(x, axis=1), axis=0), + np.fft.ifft2(x), atol=1e-6) + assert_allclose(np.fft.ifft2(x), + np.fft.ifft2(x, norm="backward"), atol=1e-6) + assert_allclose(np.fft.ifft2(x) * np.sqrt(30 * 20), + np.fft.ifft2(x, norm="ortho"), atol=1e-6) + assert_allclose(np.fft.ifft2(x) * (30. * 20.), + np.fft.ifft2(x, norm="forward"), atol=1e-6) + + def test_fftn(self): + x = random((30, 20, 10)) + 1j*random((30, 20, 10)) + assert_allclose( + np.fft.fft(np.fft.fft(np.fft.fft(x, axis=2), axis=1), axis=0), + np.fft.fftn(x), atol=1e-6) + assert_allclose(np.fft.fftn(x), + np.fft.fftn(x, norm="backward"), atol=1e-6) + assert_allclose(np.fft.fftn(x) / np.sqrt(30 * 20 * 10), + np.fft.fftn(x, norm="ortho"), atol=1e-6) + assert_allclose(np.fft.fftn(x) / (30. * 20. * 10.), + np.fft.fftn(x, norm="forward"), atol=1e-6) + + def test_ifftn(self): + x = random((30, 20, 10)) + 1j*random((30, 20, 10)) + assert_allclose( + np.fft.ifft(np.fft.ifft(np.fft.ifft(x, axis=2), axis=1), axis=0), + np.fft.ifftn(x), atol=1e-6) + assert_allclose(np.fft.ifftn(x), + np.fft.ifftn(x, norm="backward"), atol=1e-6) + assert_allclose(np.fft.ifftn(x) * np.sqrt(30 * 20 * 10), + np.fft.ifftn(x, norm="ortho"), atol=1e-6) + assert_allclose(np.fft.ifftn(x) * (30. * 20. * 10.), + np.fft.ifftn(x, norm="forward"), atol=1e-6) + + def test_rfft(self): + x = random(30) + for n in [x.size, 2*x.size]: + for norm in [None, 'backward', 'ortho', 'forward']: + assert_allclose( + np.fft.fft(x, n=n, norm=norm)[:(n//2 + 1)], + np.fft.rfft(x, n=n, norm=norm), atol=1e-6) + assert_allclose( + np.fft.rfft(x, n=n), + np.fft.rfft(x, n=n, norm="backward"), atol=1e-6) + assert_allclose( + np.fft.rfft(x, n=n) / np.sqrt(n), + np.fft.rfft(x, n=n, norm="ortho"), atol=1e-6) + assert_allclose( + np.fft.rfft(x, n=n) / n, + np.fft.rfft(x, n=n, norm="forward"), atol=1e-6) + + def test_irfft(self): + x = random(30) + assert_allclose(x, np.fft.irfft(np.fft.rfft(x)), atol=1e-6) + assert_allclose(x, np.fft.irfft(np.fft.rfft(x, norm="backward"), + norm="backward"), atol=1e-6) + assert_allclose(x, np.fft.irfft(np.fft.rfft(x, norm="ortho"), + norm="ortho"), atol=1e-6) + assert_allclose(x, np.fft.irfft(np.fft.rfft(x, norm="forward"), + norm="forward"), atol=1e-6) + + def test_rfft2(self): + x = random((30, 20)) + assert_allclose(np.fft.fft2(x)[:, :11], np.fft.rfft2(x), atol=1e-6) + assert_allclose(np.fft.rfft2(x), + np.fft.rfft2(x, norm="backward"), atol=1e-6) + assert_allclose(np.fft.rfft2(x) / np.sqrt(30 * 20), + np.fft.rfft2(x, norm="ortho"), atol=1e-6) + assert_allclose(np.fft.rfft2(x) / (30. * 20.), + np.fft.rfft2(x, norm="forward"), atol=1e-6) + + def test_irfft2(self): + x = random((30, 20)) + assert_allclose(x, np.fft.irfft2(np.fft.rfft2(x)), atol=1e-6) + assert_allclose(x, np.fft.irfft2(np.fft.rfft2(x, norm="backward"), + norm="backward"), atol=1e-6) + assert_allclose(x, np.fft.irfft2(np.fft.rfft2(x, norm="ortho"), + norm="ortho"), atol=1e-6) + assert_allclose(x, np.fft.irfft2(np.fft.rfft2(x, norm="forward"), + norm="forward"), atol=1e-6) + + def test_rfftn(self): + x = random((30, 20, 10)) + assert_allclose(np.fft.fftn(x)[:, :, :6], np.fft.rfftn(x), atol=1e-6) + assert_allclose(np.fft.rfftn(x), + np.fft.rfftn(x, norm="backward"), atol=1e-6) + assert_allclose(np.fft.rfftn(x) / np.sqrt(30 * 20 * 10), + np.fft.rfftn(x, norm="ortho"), atol=1e-6) + assert_allclose(np.fft.rfftn(x) / (30. * 20. * 10.), + np.fft.rfftn(x, norm="forward"), atol=1e-6) + + def test_irfftn(self): + x = random((30, 20, 10)) + assert_allclose(x, np.fft.irfftn(np.fft.rfftn(x)), atol=1e-6) + assert_allclose(x, np.fft.irfftn(np.fft.rfftn(x, norm="backward"), + norm="backward"), atol=1e-6) + assert_allclose(x, np.fft.irfftn(np.fft.rfftn(x, norm="ortho"), + norm="ortho"), atol=1e-6) + assert_allclose(x, np.fft.irfftn(np.fft.rfftn(x, norm="forward"), + norm="forward"), atol=1e-6) + + def test_hfft(self): + x = random(14) + 1j*random(14) + x_herm = np.concatenate((random(1), x, random(1))) + x = np.concatenate((x_herm, x[::-1].conj())) + assert_allclose(np.fft.fft(x), np.fft.hfft(x_herm), atol=1e-6) + assert_allclose(np.fft.hfft(x_herm), + np.fft.hfft(x_herm, norm="backward"), atol=1e-6) + assert_allclose(np.fft.hfft(x_herm) / np.sqrt(30), + np.fft.hfft(x_herm, norm="ortho"), atol=1e-6) + assert_allclose(np.fft.hfft(x_herm) / 30., + np.fft.hfft(x_herm, norm="forward"), atol=1e-6) + + def test_ihfft(self): + x = random(14) + 1j*random(14) + x_herm = np.concatenate((random(1), x, random(1))) + x = np.concatenate((x_herm, x[::-1].conj())) + assert_allclose(x_herm, np.fft.ihfft(np.fft.hfft(x_herm)), atol=1e-6) + assert_allclose(x_herm, np.fft.ihfft(np.fft.hfft(x_herm, + norm="backward"), norm="backward"), atol=1e-6) + assert_allclose(x_herm, np.fft.ihfft(np.fft.hfft(x_herm, + norm="ortho"), norm="ortho"), atol=1e-6) + assert_allclose(x_herm, np.fft.ihfft(np.fft.hfft(x_herm, + norm="forward"), norm="forward"), atol=1e-6) + + @pytest.mark.parametrize("op", [np.fft.fftn, np.fft.ifftn, + np.fft.rfftn, np.fft.irfftn]) + def test_axes(self, op): + x = random((30, 20, 10)) + axes = [(0, 1, 2), (0, 2, 1), (1, 0, 2), (1, 2, 0), (2, 0, 1), (2, 1, 0)] + for a in axes: + op_tr = op(np.transpose(x, a)) + tr_op = np.transpose(op(x, axes=a), a) + assert_allclose(op_tr, tr_op, atol=1e-6) + + def test_all_1d_norm_preserving(self): + # verify that round-trip transforms are norm-preserving + x = random(30) + x_norm = np.linalg.norm(x) + n = x.size * 2 + func_pairs = [(np.fft.fft, np.fft.ifft), + (np.fft.rfft, np.fft.irfft), + # hfft: order so the first function takes x.size samples + # (necessary for comparison to x_norm above) + (np.fft.ihfft, np.fft.hfft), + ] + for forw, back in func_pairs: + for n in [x.size, 2*x.size]: + for norm in [None, 'backward', 'ortho', 'forward']: + tmp = forw(x, n=n, norm=norm) + tmp = back(tmp, n=n, norm=norm) + assert_allclose(x_norm, + np.linalg.norm(tmp), atol=1e-6) + + @pytest.mark.parametrize("dtype", [np.half, np.single, np.double, + np.longdouble]) + def test_dtypes(self, dtype): + # make sure that all input precisions are accepted and internally + # converted to 64bit + x = random(30).astype(dtype) + assert_allclose(np.fft.ifft(np.fft.fft(x)), x, atol=1e-6) + assert_allclose(np.fft.irfft(np.fft.rfft(x)), x, atol=1e-6) + + +@pytest.mark.parametrize( + "dtype", + [np.float32, np.float64, np.complex64, np.complex128]) +@pytest.mark.parametrize("order", ["F", 'non-contiguous']) +@pytest.mark.parametrize( + "fft", + [np.fft.fft, np.fft.fft2, np.fft.fftn, + np.fft.ifft, np.fft.ifft2, np.fft.ifftn]) +def test_fft_with_order(dtype, order, fft): + # Check that FFT/IFFT produces identical results for C, Fortran and + # non contiguous arrays + rng = np.random.RandomState(42) + X = rng.rand(8, 7, 13).astype(dtype, copy=False) + # See discussion in pull/14178 + _tol = 8.0 * np.sqrt(np.log2(X.size)) * np.finfo(X.dtype).eps + if order == 'F': + Y = np.asfortranarray(X) + else: + # Make a non contiguous array + Y = X[::-1] + X = np.ascontiguousarray(X[::-1]) + + if fft.__name__.endswith('fft'): + for axis in range(3): + X_res = fft(X, axis=axis) + Y_res = fft(Y, axis=axis) + assert_allclose(X_res, Y_res, atol=_tol, rtol=_tol) + elif fft.__name__.endswith(('fft2', 'fftn')): + axes = [(0, 1), (1, 2), (0, 2)] + if fft.__name__.endswith('fftn'): + axes.extend([(0,), (1,), (2,), None]) + for ax in axes: + X_res = fft(X, axes=ax) + Y_res = fft(Y, axes=ax) + assert_allclose(X_res, Y_res, atol=_tol, rtol=_tol) + else: + raise ValueError() + + +@pytest.mark.skipif(IS_WASM, reason="Cannot start thread") +class TestFFTThreadSafe: + threads = 16 + input_shape = (800, 200) + + def _test_mtsame(self, func, *args): + def worker(args, q): + q.put(func(*args)) + + q = queue.Queue() + expected = func(*args) + + # Spin off a bunch of threads to call the same function simultaneously + t = [threading.Thread(target=worker, args=(args, q)) + for i in range(self.threads)] + [x.start() for x in t] + + [x.join() for x in t] + # Make sure all threads returned the correct value + for i in range(self.threads): + assert_array_equal(q.get(timeout=5), expected, + 'Function returned wrong value in multithreaded context') + + def test_fft(self): + a = np.ones(self.input_shape) * 1+0j + self._test_mtsame(np.fft.fft, a) + + def test_ifft(self): + a = np.ones(self.input_shape) * 1+0j + self._test_mtsame(np.fft.ifft, a) + + def test_rfft(self): + a = np.ones(self.input_shape) + self._test_mtsame(np.fft.rfft, a) + + def test_irfft(self): + a = np.ones(self.input_shape) * 1+0j + self._test_mtsame(np.fft.irfft, a) |