[Help-gsl] FFT phase issue

[fperr089]

Hello, I was trying out the FFT routines in GSL and I am having a problem.
 If I enter a cosine function and fourrier transform it I should obtain a
purely absorptive line in the real output and a purely dispersive line in
the imaginary output.  Although, when I try this with the raddix routine I
obtain a partially dispersive and absorptive line in the real and
immaginary output, of the same phase.  Their phases should be opposite.  I
don't know if this is an issue with the routine or if I am missing
something, please reply if you have suggestions.

Frédéric