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/* A program to test real 2d forward and inverse fast fourier transform routines */
#include <stdio.h>
#include <stdlib.h>
#include <fp.h>
#include <math.h>
#include "fftlib.h"
#include "fftext.h"
#include "fft2d.h"
#if macintosh
#include <timer.h>
#endif
#define BIPRAND(a) (2.0/(RAND_MAX+1.0)*a-1.0)
void main(){
long N2 = 64; /* the number of rows in 2d ffts, must be power of 2 */
long N = 256; /* the number of cols in 2d ffts, must be power of 2 */
float *a;
float maxerrfft;
long i1;
long TheErr;
long M;
long M2;
FILE *fdataout; /* output file */
unsigned int randseed = 777;
int rannum;
#if macintosh
UnsignedWide TheTime1;
Microseconds(&TheTime1);
randseed = TheTime1.lo;
#endif
printf(" %6d Byte Floats \n", sizeof(a[0]));
printf(" randseed = %10u\n", randseed);
srand(randseed);
M = roundtol(LOG2(N));
N = POW2(M);
M2 = roundtol(LOG2(N2));
N2 = POW2(M2);
printf("fft size = %6d X%6d, ", N2, N);
TheErr = 0;
if(!TheErr){
TheErr = fft2dInit(M2, M);
}
a = (float *) malloc(N2*N*sizeof(float) );
if (a == 0) TheErr = 2;
if(!TheErr){
fdataout = fopen("fftdat.dr2", "wb");
if (fdataout == NULL) TheErr = -50;
}
if(!TheErr){
/* write sizes to fdataout */
fwrite(&N, sizeof(N), 1, fdataout);
fwrite(&N2, sizeof(N2), 1, fdataout);
/* set up a simple test case and write to fdataout */
for (i1=0; i1<N2*N; i1++){
rannum = rand();
a[i1] = BIPRAND(rannum);
}
fwrite(a, N2*N*sizeof(float), 1, fdataout);
/* real, 2d fast fourier transform */
rfft2d(a, M2, M);
/* write out answer */
fwrite(a, N2*N*sizeof(float), 1, fdataout);
fclose(fdataout);
/* compute and check inverse transform */
rifft2d(a, M2, M);
maxerrfft = 0;
srand(randseed);
for (i1=0; i1<N2*N; i1++){
rannum = rand();
maxerrfft = fmax(maxerrfft, fabs(BIPRAND(rannum)-a[i1]));
}
printf("maxerr rfft = %6.4e\n", maxerrfft);
free(a);
fft2dFree();
}
else{
if(TheErr==2) printf(" out of memory \n");
else printf(" error \n");
fft2dFree();
}
printf(" Done. \n");
return;
}
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