torch.fft.ifft(input, n=None, dim=-1, norm=None, *, out=None) Tensor

Computes the one dimensional inverse discrete Fourier transform of input.


Supports torch.half and torch.chalf on CUDA with GPU Architecture SM53 or greater. However it only supports powers of 2 signal length in every transformed dimension.

  • input (Tensor) – the input tensor

  • n (int, optional) – Signal length. If given, the input will either be zero-padded or trimmed to this length before computing the IFFT.

  • dim (int, optional) – The dimension along which to take the one dimensional IFFT.

  • norm (str, optional) –

    Normalization mode. For the backward transform (ifft()), these correspond to:

    • "forward" - no normalization

    • "backward" - normalize by 1/n

    • "ortho" - normalize by 1/sqrt(n) (making the IFFT orthonormal)

    Calling the forward transform (fft()) with the same normalization mode will apply an overall normalization of 1/n between the two transforms. This is required to make ifft() the exact inverse.

    Default is "backward" (normalize by 1/n).

Keyword Arguments

out (Tensor, optional) – the output tensor.


>>> t = torch.tensor([ 6.+0.j, -2.+2.j, -2.+0.j, -2.-2.j])
>>> torch.fft.ifft(t)
tensor([0.+0.j, 1.+0.j, 2.+0.j, 3.+0.j])


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