def fftn(a, s=None, axes=None, norm=None):
"""Compute the N-dimensional FFT.
Args:
a (cupy.ndarray): Array to be transform.
s (None or tuple of ints): Shape of the transformed axes of the
output. If ``s`` is not given, the lengths of the input along the
axes specified by ``axes`` are used.
axes (tuple of ints): Axes over which to compute the FFT.
norm (None or ``"ortho"``): Keyword to specify the normalization mode.
Returns:
cupy.ndarray:
The transformed array which shape is specified by ``s`` and type
will convert to complex if the input is other.
.. seealso:: :func:`numpy.fft.fftn`
"""
return cufft.fft(a, s, axes, norm, cupy.cuda.cufft.CUFFT_FORWARD)
def fft(a, n=None, axis=-1, norm=None):
"""Compute the one-dimensional FFT.
Args:
a (cupy.ndarray): Array to be transform.
n (None or int): Length of the transformed axis of the output. If ``n``
is not given, the length of the input along the axis specified by
``axis`` is used.
axis (int): Axis over which to compute the FFT.
norm (None or ``"ortho"``): Keyword to specify the normalization mode.
Returns:
cupy.ndarray:
The transformed array which shape is specified by ``n`` and type
will convert to complex if the input is other.
.. seealso:: :func:`numpy.fft.fft`
"""
return cufft.fft(a, (n, ), (axis, ), norm, cupy.cuda.cufft.CUFFT_FORWARD)
def rfft2(a, s=None, axes=(-2, -1), norm=None):
"""Compute the two-dimensional FFT for real input.
Args:
a (cupy.ndarray): Array to be transform.
s (None or tuple of ints): Shape to use from the input. If ``s`` is not
given, the lengths of the input along the axes specified by
``axes`` are used.
axes (tuple of ints): Axes over which to compute the FFT.
norm (None or ``"ortho"``): Keyword to specify the normalization mode.
Returns:
cupy.ndarray:
The transformed array which shape is specified by ``s`` and type
will convert to complex if the input is other. The length of the
last axis transformed will be ``s[-1]//2+1``.
.. seealso:: :func:`numpy.fft.rfft2`
"""
return cufft.fft(a, s, axes, norm, cupy.cuda.cufft.CUFFT_FORWARD, 'R2C')
def irfftn(a, s=None, axes=None, norm=None):
"""Compute the N-dimensional inverse FFT for real input.
Args:
a (cupy.ndarray): Array to be transform.
s (None or tuple of ints): Shape of the output. If ``s`` is not given,
they are determined from the lengths of the input along the axes
specified by ``axes``.
axes (tuple of ints): Axes over which to compute the FFT.
norm (None or ``"ortho"``): Keyword to specify the normalization mode.
Returns:
cupy.ndarray:
The transformed array which shape is specified by ``s`` and type
will convert to complex if the input is other. If ``s`` is not
given, the length of final transformed axis of output will be
``2*(m-1)`` where `m` is the length of the final transformed axis
of the input.
.. seealso:: :func:`numpy.fft.irfftn`
"""
return cufft.fft(a, s, axes, norm, cupy.cuda.cufft.CUFFT_INVERSE, 'C2R')
def irfft(a, n=None, axis=-1, norm=None):
"""Compute the one-dimensional inverse FFT for real input.
Args:
a (cupy.ndarray): Array to be transform.
n (None or int): Length of the transformed axis of the output. For
``n`` output points, ``n//2+1`` input points are necessary. If
``n`` is not given, it is determined from the length of the input
along the axis specified by ``axis``.
axis (int): Axis over which to compute the FFT.
norm (None or ``"ortho"``): Keyword to specify the normalization mode.
Returns:
cupy.ndarray:
The transformed array which shape is specified by ``n`` and type
will convert to complex if the input is other. If ``n`` is not
given, the length of the transformed axis is`2*(m-1)` where `m`
is the length of the transformed axis of the input.
.. seealso:: :func:`numpy.fft.irfft`
"""
return cufft.fft(a, (n, ), (axis, ), norm, cupy.cuda.cufft.CUFFT_INVERSE,
'C2R')