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  1. #include <iostream>
  2. #include <cstdlib>
  3. #include <iomanip>
  4. #include <mpi.h>
  5.  
  6. using namespace std;
  7.  
  8. int main(int argc, char** argv) {
  9.     MPI_Init(&argc, &argv);
  10.     int rank, size;
  11.     MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  12.     MPI_Comm_size(MPI_COMM_WORLD, &size);
  13.  
  14.     const int NRA = 4, NCA = 3, NCB = 2; // Example dimensions of matrices
  15.     const int MASTER = 0;
  16.     double start_time;
  17.     start_time = MPI_Wtime();
  18.  
  19.     double *a = nullptr;
  20.     double *b = new double[NCA * NCB];
  21.     double *c = new double[NRA * NCB];
  22.  
  23.     if (rank == MASTER) {
  24.         cout << "Number of processes: " << size << endl;
  25.         cout << "Matrix A" << endl;
  26.         a = new double[NRA * NCA];
  27.         for (int i = 0; i < NRA; i++) {
  28.             for (int j = 0; j < NCA; j++) {
  29.                 a[i * NCA + j] = 1 + i + j; // Example initialization
  30.                 cout << setw(5) << a[i * NCA + j] << " ";
  31.             }
  32.             cout << endl;
  33.         }
  34.  
  35.         cout << "Matrix B" << endl;
  36.         for (int i = 0; i < NCA; i++) {
  37.             for (int j = 0; j < NCB; j++) {
  38.                 b[i * NCB + j] = 1 + i * j; // Example initialization
  39.                 cout << setw(5) << b[i * NCB + j] << " ";
  40.             }
  41.             cout << endl;
  42.         }
  43.     }
  44.  
  45.     // Broadcast Matrix B to all processes
  46.     MPI_Bcast(b, NCA * NCB, MPI_DOUBLE, MASTER, MPI_COMM_WORLD);
  47.  
  48.     // Allocate memory for Matrix A on all processes
  49.     if (rank != MASTER) {
  50.         a = new double[NRA * NCA];
  51.     }
  52.  
  53.     // Broadcast Matrix A to all processes
  54.     MPI_Bcast(a, NRA * NCA, MPI_DOUBLE, MASTER, MPI_COMM_WORLD);
  55.  
  56.     // Perform matrix multiplication
  57.     for (int i = 0; i < NRA; i++) {
  58.         for (int j = 0; j < NCB; j++) {
  59.             c[i * NCB + j] = 0;
  60.             for (int k = 0; k < NCA; k++) {
  61.                 c[i * NCB + j] += a[i * NCA + k] * b[k * NCB + j];
  62.             }
  63.         }
  64.     }
  65.  
  66.     // Master process prints the resulting matrix C
  67.     if (rank == MASTER) {
  68.         cout << "Matrix C" << endl;
  69.         for (int i = 0; i < NRA; i++) {
  70.             for (int j = 0; j < NCB; j++) {
  71.                 cout << setw(5) << c[i * NCB + j] << " ";
  72.             }
  73.             cout << endl;
  74.         }
  75.     }
  76.  
  77.     // Free allocated memory
  78.     delete[] b;
  79.     delete[] c;
  80.     if (rank == MASTER) {
  81.         delete[] a;
  82.     }
  83.  
  84.     MPI_Finalize();
  85.     return 0;
  86. }
  87.  
Success #stdin #stdout #stderr 0.23s 40632KB
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Standard input is empty
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Standard output is empty
stderr
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Error: unexpected symbol in "using namespace"
Execution halted
https://ideone.com/pAfcVs
language:
R (R 3.5.2)
created:
19 hours ago
visibility:
public

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