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/* A program to test real forward and inverse fast fourier transform routines */
#include <NR.H> /* uses realft from numerical recipes in C to verify riffts */
/*change fmin in numerical recipes to fminnr to avoid conflict with fp.h */
#include <stdio.h>
#include <stdlib.h>
#include <fp.h>
#include <math.h>
#include "fftlib.h"
#include "fftext.h"
#if macintosh
#include <timer.h>
#endif
#define NSIZES 24 /* the number of different fft sizes to test */
#define BIPRAND(a) (2.0/(RAND_MAX+1.0)*a-1.0)
void main(){
long fftSize[NSIZES] = /* size of FFTs, must be powers of 2 */
{2, 4, 8, 16, 32, 64, 128, 256,
512, 1024, 2048, 4096, 8192, 16384, 32768, 65536,
131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216};
float *a;
const long N2 = 2; /* the number ffts to test at each size */
long isize;
long i1;
long i2;
long TheErr;
long N;
long M;
float maxerrifft;
float maxerrfft;
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);
for (isize = 0; isize < NSIZES; isize++){
srand(randseed);
N = fftSize[isize];
printf("rffts size = %8d, ", N);
M = roundtol(LOG2(N));
TheErr = 0;
TheErr = fftInit(M);
if(!TheErr){
a = (float *) malloc(N2*N*sizeof(float) );
if (a == 0) TheErr = 2;
}
if(!TheErr){
/* set up a simple test case */
for (i1=0; i1<N2*N; i1++){
rannum = rand();
a[i1] = BIPRAND(rannum);
}
/* first use realft from numerical recipes in C to verify riffts */
/* unfortunately numerical recipes in C uses backwards time */
/* forward fft, so our answer comes out time reversed */
for (i2=0; i2<N2; i2++){
realft((a+i2*N)-1, N, 1);
}
riffts(a, M, N2);
srand(randseed);
for (i2=0; i2<N2; i2++){
rannum = rand();
maxerrifft = fabs(BIPRAND(rannum)-a[i2*N]);
for (i1=1; i1<N; i1++){
rannum = rand();
maxerrifft = fmax(maxerrifft, fabs(BIPRAND(rannum)-a[i2*N+N-i1]));
}
}
printf("maxerrifft = %6.4e, ", maxerrifft);
/* now use iffts to verify ffts */
srand(randseed);
for (i1=0; i1<N2*N; i1++){
rannum = rand();
a[i1] = BIPRAND(rannum);
}
riffts(a, M, N2);
rffts(a, M, N2);
maxerrfft = 0;
srand(randseed);
for (i1=0; i1<N2*N; i1++){
rannum = rand();
maxerrfft = fmax(maxerrfft, fabs(BIPRAND(rannum)-a[i1]));
}
printf("maxerrfft = %6.4e\n", maxerrfft);
fftFree();
free(a);
a = 0;
}
else{
if(TheErr==2) printf(" out of memory \n");
else printf(" error \n");
fftFree();
}
}
printf(" Done. \n");
return;
}
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