xrscipy.fftpack.ifft

xrscipy.fftpack.ifft(x, coord, n=None)

Return discrete inverse Fourier transform of real or complex sequence.

The returned complex array contains y(0), y(1),..., y(n-1), where

y(j) = (x * exp(2*pi*sqrt(-1)*j*np.arange(n)/n)).mean().

Parameters:

  • obj (xarray object) – Transformed data to invert.

  • coord (string) – Coordinate along which the ifft’s are computed. The coordinate must be evenly spaced.

  • n (int, optional) – Length of the inverse Fourier transform. If n < x.shape[axis], x is truncated. If n > x.shape[axis], x is zero-padded. The default results in n = x.shape[axis].

Returns:

ifft – The inverse discrete Fourier transform.

Return type:

ndarray of floats

See also

fft

Forward FFT

numpy.fftpack.ifft

scipy.fft.ifft : Original scipy implementation

Notes

Both single and double precision routines are implemented. Half precision inputs will be converted to single precision. Non-floating-point inputs will be converted to double precision. Long-double precision inputs are not supported.

This function is most efficient when n is a power of two, and least efficient when n is prime.

If the data type of x is real, a “real IFFT” algorithm is automatically used, which roughly halves the computation time.

Examples

>>> from scipy.fftpack import fft, ifft
>>> import numpy as np
>>> x = np.arange(5)
>>> np.allclose(ifft(fft(x)), x, atol=1e-15)  # within numerical accuracy.
True