scipy.fftpack.irfft

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

[y(0),y(1),...,y(n-1)]

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__