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Diffstat (limited to 'libgomp/testsuite/libgomp.c/omp_matvec.c')
-rw-r--r-- | libgomp/testsuite/libgomp.c/omp_matvec.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/libgomp/testsuite/libgomp.c/omp_matvec.c b/libgomp/testsuite/libgomp.c/omp_matvec.c new file mode 100644 index 000000000..12b8c6896 --- /dev/null +++ b/libgomp/testsuite/libgomp.c/omp_matvec.c @@ -0,0 +1,72 @@ +/****************************************************************************** +* OpenMP Example - Matrix-vector multiplication - C/C++ Version +* FILE: omp_matvec.c +* DESCRIPTION: +* This example multiplies all row i elements of matrix A with vector +* element b(i) and stores the summed products in vector c(i). A total is +* maintained for the entire matrix. Performed by using the OpenMP loop +* work-sharing construct. The update of the shared global total is +* serialized by using the OpenMP critical directive. +* SOURCE: Blaise Barney 5/99 +* LAST REVISED: +******************************************************************************/ + +#include <omp.h> +#include <stdio.h> +#define SIZE 10 + + +main () +{ + +float A[SIZE][SIZE], b[SIZE], c[SIZE], total; +int i, j, tid; + +/* Initializations */ +total = 0.0; +for (i=0; i < SIZE; i++) + { + for (j=0; j < SIZE; j++) + A[i][j] = (j+1) * 1.0; + b[i] = 1.0 * (i+1); + c[i] = 0.0; + } +printf("\nStarting values of matrix A and vector b:\n"); +for (i=0; i < SIZE; i++) + { + printf(" A[%d]= ",i); + for (j=0; j < SIZE; j++) + printf("%.1f ",A[i][j]); + printf(" b[%d]= %.1f\n",i,b[i]); + } +printf("\nResults by thread/row:\n"); + +/* Create a team of threads and scope variables */ +#pragma omp parallel shared(A,b,c,total) private(tid,i) + { + tid = omp_get_thread_num(); + +/* Loop work-sharing construct - distribute rows of matrix */ +#pragma omp for private(j) + for (i=0; i < SIZE; i++) + { + for (j=0; j < SIZE; j++) + c[i] += (A[i][j] * b[i]); + + /* Update and display of running total must be serialized */ + #pragma omp critical + { + total = total + c[i]; + printf(" thread %d did row %d\t c[%d]=%.2f\t",tid,i,i,c[i]); + printf("Running total= %.2f\n",total); + } + + } /* end of parallel i loop */ + + } /* end of parallel construct */ + +printf("\nMatrix-vector total - sum of all c[] = %.2f\n\n",total); + + return 0; +} + |