scipy.fftpack.irfft(x, n=None, axis=-1, overwrite_x=0)

irfft(x, n=None, axis=-1, overwrite_x=0) -> y

Return inverse discrete Fourier transform of real sequence x. The contents of x is interpreted as the output of rfft(..) function.

The returned real array contains
where for n is even
y(j) = 1/n (sum[k=1..n/2-1] (x[2*k-1]+sqrt(-1)*x[2*k])
  • exp(sqrt(-1)*j*k* 2*pi/n)
  • c.c. + x[0] + (-1)**(j) x[n-1])
and for n is odd
y(j) = 1/n (sum[k=1..(n-1)/2] (x[2*k-1]+sqrt(-1)*x[2*k])
  • exp(sqrt(-1)*j*k* 2*pi/n)
  • c.c. + x[0])

c.c. denotes complex conjugate of preceeding expression.

Optional input: see rfft.__doc__

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