triad

OpenMP/Code/triad.c

+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <omp.h>
+
+void triad(const float* a,const float* b,const float* c,float* d, const size_t n,const size_t m)
+{
+    for(size_t i=0;i<n;i++){
+        #pragma omp parallel for
+        for(size_t j=0;j<m;j++){
+            d[j]=c[j]+a[j]*b[j];
+        }
+    }
+}
+
+int main(int argc,char** argv)
+{
+    size_t m;//aka long unsigned int
+
+    if(argc==2){
+        m = atoi(argv[1]);
+    }else{
+        printf("need an argument (vector length)!\n");
+    }
+
+    unsigned long long int n=(1ULL<<32);
+    n /= m;
+
+    float *a,*b,*c,*d;
+    a=(float*)malloc(m*sizeof(float));
+    b=(float*)malloc(m*sizeof(float));
+    c=(float*)malloc(m*sizeof(float));
+    d=(float*)malloc(m*sizeof(float));
+
+    for(int i=0;i<m;i++){
+        a[i]=i+1;
+        b[i]=i+2;
+        c[i]=i+3;
+    }
+
+    struct timespec tstart,tstop;
+    clock_gettime(CLOCK_MONOTONIC,&tstart);
+    triad(a,b,c,d,n,m);
+    clock_gettime(CLOCK_MONOTONIC,&tstop);
+
+    double elapsed=(tstop.tv_sec-tstart.tv_sec)+(tstop.tv_nsec-tstart.tv_nsec)/1e9;
+    printf("m=%lu %llu \t elapsed time: %f \t Mflops: %f\n",m,n,elapsed,(2.0*n*m/elapsed)/(1024.0*1024.0));
+
+    free(a);
+    free(b);
+    free(c);
+    free(d);
+}