Révision 278
| ETSN/DFT.c (revision 278) | ||
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/* Simple Discrete Fourier Transform implemented in C and OpenMP/C */ |
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/* compilation with : gcc -fopenmp -O3 -o DFT DFT.c -lm -lgomp */ |
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#include <math.h> |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <sys/time.h> |
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#define PI 3.141592653589793 |
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#define MYFLOAT float |
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void MyDFT(MYFLOAT *A, MYFLOAT *B, MYFLOAT *a, MYFLOAT *b,int size) |
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{
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for (uint j=0;j<size;j++) |
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{
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MYFLOAT At=0.,Bt=0.; |
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for (uint i=0; i<size;i++) |
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{
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At+=a[i]*cos(2.*PI*(MYFLOAT)(j*i)/(MYFLOAT)size)-b[i]*sin(2.*PI*(MYFLOAT)(j*i)/(MYFLOAT)size); |
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Bt+=a[i]*sin(2.*PI*(MYFLOAT)(j*i)/(MYFLOAT)size)+b[i]*cos(2.*PI*(MYFLOAT)(j*i)/(MYFLOAT)size); |
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} |
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A[j]=At; |
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B[j]=Bt; |
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} |
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} |
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void MyDFTOMP(MYFLOAT *A, MYFLOAT *B, MYFLOAT *a, MYFLOAT *b,int size) |
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{
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#pragma omp parallel for |
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for (uint j=0;j<size;j++) |
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{
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MYFLOAT At=0.,Bt=0.; |
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for (uint i=0; i<size;i++) |
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{
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At+=a[i]*cos(2.*PI*(MYFLOAT)(j*i)/(MYFLOAT)size)-b[i]*sin(2.*PI*(MYFLOAT)(j*i)/(MYFLOAT)size); |
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Bt+=a[i]*sin(2.*PI*(MYFLOAT)(j*i)/(MYFLOAT)size)+b[i]*cos(2.*PI*(MYFLOAT)(j*i)/(MYFLOAT)size); |
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} |
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A[j]=At; |
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B[j]=Bt; |
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} |
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} |
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int main(int argc,char *argv[]) |
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{
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float *a,*b,*A,*B; |
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int size=1024; |
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struct timeval tv1,tv2; |
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if (argc > 1) {
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size=(int)atoll(argv[1]); |
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} |
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else {
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printf("\n\tPi : Estimate DFT\n\n\t\t#1 : size (default 1024)\n\n");
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} |
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a=(float*)malloc(size*sizeof(MYFLOAT)); |
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b=(float*)malloc(size*sizeof(MYFLOAT)); |
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A=(float*)malloc(size*sizeof(MYFLOAT)); |
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B=(float*)malloc(size*sizeof(MYFLOAT)); |
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for (int i=0;i<size;i++) |
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{
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a[i]=1.; |
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b[i]=1.; |
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A[i]=0.; |
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A[i]=0.; |
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} |
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gettimeofday(&tv1, NULL); |
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MyDFT(A,B,a,b,size); |
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gettimeofday(&tv2, NULL); |
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MYFLOAT elapsed=(MYFLOAT)((tv2.tv_sec-tv1.tv_sec) * 1000000L + |
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(tv2.tv_usec-tv1.tv_usec))/1000000; |
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gettimeofday(&tv1, NULL); |
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MyDFTOMP(A,B,a,b,size); |
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gettimeofday(&tv2, NULL); |
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MYFLOAT elapsedOMP=(MYFLOAT)((tv2.tv_sec-tv1.tv_sec) * 1000000L + |
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(tv2.tv_usec-tv1.tv_usec))/1000000; |
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/* printf("A=["); */
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/* for (int i=0;i<size;i++) */ |
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/* { */
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/* printf("%.2f ",A[i]); */
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/* } */ |
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/* printf(" ]\n\n"); */
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/* printf("B=["); */
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/* for (int i=0;i<size;i++) */ |
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/* { */
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/* printf("%.2f ",B[i]); */
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/* } */ |
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/* printf(" ]\n\n"); */
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printf("\nA[0]=%.3f A[%i]=%.3f\n",A[0],size,A[size-1]);
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printf("B[0]=%.3f B[%i]=%.3f\n\n",B[0],size,B[size-1]);
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printf("Elapsed Time: %.3f\n",elapsed);
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printf("OMP Elapsed Time: %.3f\n",elapsedOMP);
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printf("NaiveRate: %.i\n",(int)((float)size/elapsed));
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printf("OMPRate: %.i\n",(int)((float)size/elapsedOMP));
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free(a); |
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free(b); |
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free(A); |
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free(B); |
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} |
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