mirror of
https://github.com/cookiengineer/audacity
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122 lines
2.6 KiB
C
122 lines
2.6 KiB
C
/* A program to test real forward and inverse fast fourier transform routines */
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#include <NR.H> /* uses realft from numerical recipes in C to verify riffts */
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/*change fmin in numerical recipes to fminnr to avoid conflict with fp.h */
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#include <stdio.h>
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#include <stdlib.h>
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#include <fp.h>
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#include <math.h>
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#include "fftlib.h"
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#include "fftext.h"
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#if macintosh
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#include <timer.h>
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#endif
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#define NSIZES 24 /* the number of different fft sizes to test */
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#define BIPRAND(a) (2.0/(RAND_MAX+1.0)*a-1.0)
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void main(){
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long fftSize[NSIZES] = /* size of FFTs, must be powers of 2 */
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{2, 4, 8, 16, 32, 64, 128, 256,
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512, 1024, 2048, 4096, 8192, 16384, 32768, 65536,
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131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216};
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float *a;
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const long N2 = 2; /* the number ffts to test at each size */
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long isize;
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long i1;
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long i2;
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long TheErr;
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long N;
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long M;
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float maxerrifft;
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float maxerrfft;
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unsigned int randseed = 777;
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int rannum;
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#if macintosh
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UnsignedWide TheTime1;
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Microseconds(&TheTime1);
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randseed = TheTime1.lo;
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#endif
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printf(" %6d Byte Floats \n", sizeof(a[0]));
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printf(" randseed = %10u\n", randseed);
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for (isize = 0; isize < NSIZES; isize++){
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srand(randseed);
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N = fftSize[isize];
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printf("rffts size = %8d, ", N);
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M = roundtol(LOG2(N));
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TheErr = 0;
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TheErr = fftInit(M);
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if(!TheErr){
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a = (float *) malloc(N2*N*sizeof(float) );
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if (a == 0) TheErr = 2;
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}
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if(!TheErr){
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/* set up a simple test case */
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for (i1=0; i1<N2*N; i1++){
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rannum = rand();
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a[i1] = BIPRAND(rannum);
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}
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/* first use realft from numerical recipes in C to verify riffts */
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/* unfortunately numerical recipes in C uses backwards time */
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/* forward fft, so our answer comes out time reversed */
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for (i2=0; i2<N2; i2++){
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realft((a+i2*N)-1, N, 1);
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}
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riffts(a, M, N2);
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srand(randseed);
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for (i2=0; i2<N2; i2++){
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rannum = rand();
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maxerrifft = fabs(BIPRAND(rannum)-a[i2*N]);
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for (i1=1; i1<N; i1++){
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rannum = rand();
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maxerrifft = fmax(maxerrifft, fabs(BIPRAND(rannum)-a[i2*N+N-i1]));
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}
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}
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printf("maxerrifft = %6.4e, ", maxerrifft);
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/* now use iffts to verify ffts */
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srand(randseed);
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for (i1=0; i1<N2*N; i1++){
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rannum = rand();
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a[i1] = BIPRAND(rannum);
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}
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riffts(a, M, N2);
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rffts(a, M, N2);
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maxerrfft = 0;
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srand(randseed);
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for (i1=0; i1<N2*N; i1++){
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rannum = rand();
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maxerrfft = fmax(maxerrfft, fabs(BIPRAND(rannum)-a[i1]));
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}
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printf("maxerrfft = %6.4e\n", maxerrfft);
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fftFree();
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free(a);
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a = 0;
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}
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else{
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if(TheErr==2) printf(" out of memory \n");
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else printf(" error \n");
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fftFree();
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}
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}
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printf(" Done. \n");
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return;
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}
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