scipy.fftpack.shift

scipy.fftpack.shift(x, a, period=2*pi) → y

Shift periodic sequence x by a: y(u) = x(u+a).

If x_j and y_j are Fourier coefficients of periodic functions x and y, respectively, then

y_j = exp(j*a*2*pi/period*sqrt(-1)) * x_f

Optional input:

period

The period of the sequences x and y. Default period is 2*pi.