numpy.fft.irfft

numpy.fft.irfft(a, n=None, axis=-1)

Compute the one-dimensional inverse fft for real input.

Parameters:

a : array

Input array with real data type.

n : int

Length of the fft.

axis : int

Axis over which to compute the fft.

See also

rfft

Notes

Return the real valued n point inverse discrete Fourier transform of a, where a contains the nonnegative frequency terms of a Hermite-symmetric sequence. n is the length of the result, not the input. If n is not supplied, the default is 2*(len(a)-1). If you want the length of the result to be odd, you have to say so.

If you specify an n such that a must be zero-padded or truncated, the extra/removed values will be added/removed at high frequencies. One can thus resample a series to m points via Fourier interpolation by: a_resamp = irfft(rfft(a), m).

Within numerical accuracy irfft is the inverse of rfft:

irfft(rfft(a), len(a)) == a