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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <time.h>
  4. #ifdef _OPENMP
  5. #include <omp.h>
  6. #endif
  7.  
  8. #define N 500  // Define the size of the matrix
  9.  
  10. void initializeMatrix(int matrix[N][N]) {
  11.     for (int i = 0; i < N; i++) {
  12.         for (int j = 0; j < N; j++) {
  13.             matrix[i][j] = rand() % 10; // Random values between 0 and 9
  14.         }
  15.     }
  16. }
  17.  
  18. void printMatrix(int matrix[N][N]) {
  19.     for (int i = 0; i < N; i++) {
  20.         for (int j = 0; j < N; j++) {
  21.             printf("%d ", matrix[i][j]);
  22.         }
  23.         printf("\n");
  24.     }
  25. }
  26.  
  27. void multiplyMatrices(int A[N][N], int B[N][N], int C[N][N]) {
  28.     #ifdef _OPENMP
  29.     #pragma omp parallel for collapse(2)
  30.     #endif
  31.     for (int i = 0; i < N; i++) {
  32.         for (int j = 0; j < N; j++) {
  33.             C[i][j] = 0;
  34.             for (int k = 0; k < N; k++) {
  35.                 C[i][j] += A[i][k] * B[k][j];
  36.             }
  37.         }
  38.     }
  39. }
  40.  
  41. int main() {
  42.     srand(time(0));
  43.  
  44.     int A[N][N], B[N][N], C[N][N] = {0};
  45.  
  46.     initializeMatrix(A);
  47.     initializeMatrix(B);
  48.  
  49.     double start, end;
  50.     #ifdef _OPENMP
  51.     start = omp_get_wtime();
  52.     #else
  53.     start = (double)clock() / CLOCKS_PER_SEC;
  54.     #endif
  55.  
  56.     multiplyMatrices(A, B, C);
  57.  
  58.     #ifdef _OPENMP
  59.     end = omp_get_wtime();
  60.     #else
  61.     end = (double)clock() / CLOCKS_PER_SEC;
  62.     #endif
  63.  
  64.     printf("Time taken for parallel matrix multiplication: %f seconds.\n", end - start);
  65.  
  66.     return 0;
  67. }
  68.  
Success #stdin #stdout 0.21s 5292KB
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Standard input is empty
stdout
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Time taken for parallel matrix multiplication: 0.191500 seconds.
https://ideone.com/J4Mvg0
language:
C (gcc 8.3)
created:
3 hours ago
visibility:
public

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