C06FCF is the NAG routine for finding the FFT of a one-dimensional sequence of complex data values. The routine performs a forward transform. To do an inverse transform the complex conjugate of the input data is taken before calling C06FCF (using C06GCF), and the complex conjugate of the output data is taken on return from C06FCF.
The steps involved in replacing C06FCF calls with equivalent FFTPACK calls are listed separately for forward and inverse transforms.
PDA [1ex