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ifft#

ivy.ifft(x, dim, *, norm='backward', n=None, out=None)[source]#

Compute the one dimensional discrete Fourier transform given input at least 1-D input x.

Parameters:

  • x (Union[Array, NativeArray]) – Input volume […,d_in,…], where d_in indicates the dimension that needs IFFT.

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

  • norm (str, default: 'backward') – Optional argument, “backward”, “ortho” or “forward”. Defaults to be “backward”. “backward” indicates no normalization. “ortho” indicates normalization by $frac{1}{sqrt{n}}$. “forward” indicates normalization by $frac{1}{n}$.

  • n (Optional[Union[int, Tuple[int]]], default: None) – Optional argument indicating the sequence length, if given, the input would be padded with zero or truncated to length n before performing IFFT. Should be a integer greater than 1.

  • out (Optional[Array], default: None) – Optional output array, for writing the result to. It must have a shape that the inputs broadcast to.

Return type:

Array

Returns:

ret – The result of the IFFT operation.

Examples

>>> ivy.ifft(np.exp(2j * np.pi * np.arange(8) / 8), 0)
ivy.array([-4.30636606e-17+1.43029718e-18j,  0.00000000e+00+1.53080850e-17j,
            1.43029718e-18+1.53080850e-17j,  0.00000000e+00+9.58689626e-18j,
            1.24474906e-17+2.91858728e-17j,  0.00000000e+00+1.53080850e-17j,
            2.91858728e-17+1.53080850e-17j,  1.00000000e+00-1.01435406e-16j])
>>> ivy.ifft(np.exp(2j * np.pi * np.arange(8) / 8), 0, n=16)
ivy.array([-2.15318303e-17+7.15148591e-19j,  6.25000000e-02+9.35378602e-02j,
            0.00000000e+00+7.65404249e-18j,  6.25000000e-02+4.17611649e-02j,
            7.15148591e-19+7.65404249e-18j,  6.25000000e-02+1.24320230e-02j,
            0.00000000e+00+4.79344813e-18j,  6.25000000e-02-1.24320230e-02j,
            6.22374531e-18+1.45929364e-17j,  6.25000000e-02-4.17611649e-02j,
            0.00000000e+00+7.65404249e-18j,  6.25000000e-02-9.35378602e-02j,
            1.45929364e-17+7.65404249e-18j,  6.25000000e-02-3.14208718e-01j,
            5.00000000e-01-5.07177031e-17j,  6.25000000e-02+3.14208718e-01j])
>>> ivy.ifft(np.exp(2j * np.pi * np.arange(8) / 8), 0, norm="ortho")
ivy.array([-1.21802426e-16+4.04549134e-18j,  0.00000000e+00+4.32978028e-17j,
            4.04549134e-18+4.32978028e-17j,  0.00000000e+00+2.71158374e-17j,
            3.52068201e-17+8.25501143e-17j,  0.00000000e+00+4.32978028e-17j,
            8.25501143e-17+4.32978028e-17j,  2.82842712e+00-2.86902654e-16j])
Array.ifft(self, dim, *, norm='backward', n=None, out=None)[source]#

ivy.Array instance method variant of ivy.ifft. This method simply wraps the function, and so the docstring for ivy.ifft also applies to this method with minimal changes.

Parameters:

  • self (Array) – Input volume […,d_in,…], where d_in indicates the dimension that needs IFFT.

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

  • norm (str, default: 'backward') – Optional argument, “backward”, “ortho” or “forward”. Defaults to be “backward”. “backward” indicates no normalization. “ortho” indicates normalization by 1/sqrt(n). “forward” indicates normalization by 1/n.

  • n (Optional[Union[int, Tuple[int]]], default: None) – Optional argument indicating the sequence length, if given, the input would be padded with zero or truncated to length n before performing IFFT. Should be a integer greater than 1.

  • out (Optional[Array], default: None) – Optional output array, for writing the result to. It must have a shape that the inputs broadcast to.

Return type:

Array

Returns:

ret – Array containing the transformed input.

Examples

>>> a = ivy.array((np.exp(2j * np.pi * np.arange(8) / 8)))
>>> a.ifft(0)
ivy.array([-4.30636606e-17+1.43029718e-18j,  0.00000000e+00+1.53080850e-17j,
            1.43029718e-18+1.53080850e-17j,  0.00000000e+00+9.58689626e-18j,
            1.24474906e-17+2.91858728e-17j,  0.00000000e+00+1.53080850e-17j,
            2.91858728e-17+1.53080850e-17j,  1.00000000e+00-1.01435406e-16j])
Container.ifft(self, dim, *, norm='backward', n=None, out=None)[source]#

ivy.Container instance method variant of ivy.ifft. This method simply wraps the function, and so the docstring for ivy.ifft also applies to this method with minimal changes.

Parameters:

  • self (Container) – Container containing input volumes […,d_in,…], where d_in indicates the dimension that needs IFFT.

  • dim (Union[int, Container]) – The dimension along which to take the one dimensional IFFT.

  • norm (Union[str, Container], default: 'backward') – Optional argument, “backward”, “ortho” or “forward”. Defaults to be “backward”. “backward” indicates no normalization. “ortho” indicates normalization by 1/sqrt(n). “forward” indicates normalization by 1/n.

  • n (Optional[Union[int, Tuple[int], Container]], default: None) – Optional argument indicating the sequence length, if given, the input would be padded with zero or truncated to length n before performing IFFT. Should be a integer greater than 1.

  • out (Optional[Union[Array, Container]], default: None) – Optional output array, for writing the result to. It must have a shape that the inputs broadcast to.

Returns:

ret – Container containing the transformed inputs.

Examples

>>> a = ivy.array(np.array([ 6.+0.j, -2.+2.j, -2.+0.j, -2.-2.j]))
>>> b = ivy.array(np.exp(2j * np.pi * np.arange(8) / 8))
>>> c = ivy.Container(a=a, b=b)
>>> dims = ivy.Container(a=0, b=0)
>>> c.ifft(dims)
{
a: ivy.array([0.+0.j, 1.+0.j, 2.+0.j, 3.+0.j]),
b: ivy.array([-4.30636606e-17+1.43029718e-18j, 0.00000000e+00+1.53080850e-17j,
               1.43029718e-18+1.53080850e-17j, 0.00000000e+00+9.58689626e-18j,
               1.24474906e-17+2.91858728e-17j, 0.00000000e+00+1.53080850e-17j,
               2.91858728e-17+1.53080850e-17j, 1.00000000e+00-1.01435406e-16j])
}
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