1  #include <stdio.h>
  2  #include <stdlib.h>
  3  
  4  void mxv( int m, int n, double * restrict a, double * restrict b, double * restrict c );
  5  
  6  int main( int argc, char *argv[] ) {
  7      double *a, *b, *c;
  8      int i, j, m, n, k, loopLimit;
  9      
 10      if (argc != 4) {
 11          fputs( "usage: test <loopLimit> <m> <n>", stderr );
 12          exit( EXIT_FAILURE );
 13      }
 14      
 15      loopLimit = (int)strtol( argv[1], NULL, 10 );
 16      m = (int)strtol( argv[2], NULL, 10 );
 17      n = (int)strtol( argv[3], NULL, 10 );
 18      
 19      if ( (a=(double *)malloc(m*sizeof(double))) == NULL )
 20          perror( "memory allocation for a" );
 21      if ( (b=(double *)malloc(m*n*sizeof(double))) == NULL )
 22          perror( "memory allocation for b" );
 23      if ( (c=(double *)malloc(n*sizeof(double))) == NULL )
 24          perror( "memory allocation for c" );
 25      
 26      for (j=0; j<n; j++)
 27          c[ j ] = 2.0;
 28      for (i=0; i<m; i++)
 29          for (j=0; j<n; j++)
 30              b[ i*n + j ] = i;
 31      
 32      for (k=0; k<loopLimit; k++)
 33          (void) mxv( m, n, a, b, c );
 34      
 35      free(a); free(b); free(c);
 36      return EXIT_SUCCESS;
 37  }
 38  
 39  void mxv( int m, int n, double * restrict a, double * restrict b, double * restrict c ) {
 40      int i, j;
 41  
 42  #pragma omp parallel for default(none) shared( m, n, a, b, c ) private( i, j )
 43          
 44      for (i=0; i<m; i++) {
 45          a[ i ] = 0.0;
 46          for (j=0; j<n; j++)
 47              a[ i ] += b[ i*n + j ] * c[ j ];
 48      }
 49      // end of omp parallel for
 50  }