1 /*--------------------------------*-C-*---------------------------------*
4 * ---------------------------------------------------------------------*
5 * Re[]: real value array
6 * Im[]: imaginary value array
7 * nTotal: total number of complex values
8 * nPass: number of elements involved in this pass of transform
9 * nSpan: nspan/nPass = number of bytes to increment pointer
11 * isign: exponent: +1 = forward -1 = reverse
12 * scaling: normalizing constant by which the final result is *divided*
13 * scaling == -1, normalize by total dimension of the transform
14 * scaling < -1, normalize by the square-root of the total dimension
16 * ----------------------------------------------------------------------
17 * See the comments in the code for correct usage!
24 extern void fft_free (void);
26 /* double precision routine */
27 extern int fftn (int ndim, const int dims[], double Re[], double Im[],
28 int isign, double scaling);
30 /* float precision routine */
31 extern int fftnf (int ndim, const int dims[], float Re[], float Im[],
32 int isign, double scaling);