2 ***********************************************************
3 $SNARK_Header: S N A R K 1 4 - A PICTURE RECONSTRUCTION PROGRAM $
4 $HeadURL: svn://dig.cs.gc.cuny.edu/snark/trunk/src/snark/foru_fft.cpp $
5 $LastChangedRevision: 85 $
6 $Date: 2014-07-02 16:07:08 -0400 (Wed, 02 Jul 2014) $
8 ***********************************************************
10 FFT: FAST FOURIER TRANSFORM
11 PURPOSE: PERFORM FOURIER TRANSFORM ON ARRAY X DIMENSIONED BY N
12 INVDIR = 1 : FORWARD TRANSFORM
26 void foru_class::fft(REAL* x, INTEGER* n, INTEGER invdir, REAL fact)
35 n2 = Fourie.nsize1 + 2;
39 kh = Fourie.nsize1 + 2;
40 for (k = 0; k < kh; k++)
43 if (fabs(x[k]) <= Consts.zero)
51 kh = Fourie.nsize2 * (Fourie.nsize2 + 2);
53 for (k = 0; k < kh; k++)