dpnp.fft.rfft2

dpnp.fft.rfft2(a, s=None, axes=(-2, -1), norm=None, out=None)[source]

Compute the 2-dimensional FFT of a real array.

For full documentation refer to numpy.fft.rfft2.

Parameters:

  • a ({dpnp.ndarray, usm_ndarray}) -- Input array, taken to be real.

  • s ({None, sequence of ints}, optional) -- Shape (length of 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 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 it is -1, the whole input is used (no padding/trimming). If s is not given, the shape of the input along the axes specified by axes is used. If s is not None, axes must not be None either. Default: None.

  • axes ({None, 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. If s is specified, the corresponding axes to be transformed must be explicitly specified too. A one-element sequence means that a one-dimensional FFT is performed. An empty sequence means that no FFT is performed. Default: (-2, -1).

  • norm ({None, "backward", "ortho", "forward"}, optional) -- Normalization mode (see dpnp.fft). Indicates which direction of the forward/backward pair of transforms is scaled and with what normalization factor. None is an alias of the default option "backward". Default: "backward".

  • out ({None, dpnp.ndarray or usm_ndarray of complex dtype}, optional) -- If provided, the result will be placed in this array. It should be of the appropriate dtype and shape for the last transformation (consistent with the choice of s). Default: None.

Returns:

out -- The truncated or zero-padded input, transformed along the axes indicated by axes, or the last two axes if axes is not given.

Return type:

dpnp.ndarray of complex dtype

See also

dpnp.fft

Overall view of discrete Fourier transforms, with definitions and conventions used.

dpnp.fft.rfft

The one-dimensional FFT of real input.

dpnp.fft.rfftn

The n-dimensional FFT of real input.

dpnp.fft.irfft2

The inverse two-dimensional real FFT.

Notes

This is just dpnp.fft.rfftn with different default behavior. For more details see dpnp.fft.rfftn.

Examples

>>> import dpnp as np
>>> 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        ]])