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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <mpi.h>
  4.  
  5. #define ARRAY_SIZE 1000
  6.  
  7. int main(int argc, char *argv[]) {
  8.     int rank, size;
  9.     int max_local, max_global;
  10.     int *data = NULL;
  11.     int i;
  12.  
  13.     MPI_Init(&argc, &argv);
  14.     MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  15.     MPI_Comm_size(MPI_COMM_WORLD, &size);
  16.  
  17.     // Allocate memory for data array
  18.     data = (int*)malloc(sizeof(int) * ARRAY_SIZE);
  19.  
  20.     // Generate random numbers
  21.     srand(rank);  // seed based on rank for different numbers in each process
  22.     for (i = 0; i < ARRAY_SIZE; i++) {
  23.         data[i] = rand();
  24.     }
  25.  
  26.     // Find local max
  27.     max_local = data[0];
  28.     for (i = 1; i < ARRAY_SIZE; i++) {
  29.         if (data[i] > max_local) {
  30.             max_local = data[i];
  31.         }
  32.     }
  33.  
  34.     // Reduce all local max values to find global max
  35.     MPI_Reduce(&max_local, &max_global, 1, MPI_INT, MPI_MAX, 0, MPI_COMM_WORLD);
  36.  
  37.     // Print result
  38.     if (rank == 0) {
  39.         printf("The maximum number is: %d\n", max_global);
  40.     }
  41.  
  42.     // Cleanup
  43.     free(data);
  44.     MPI_Finalize();
  45.  
  46.     return 0;
  47. }
  48.  
Success #stdin #stdout #stderr 0.32s 40404KB
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Standard input is empty
stdout
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Standard output is empty
stderr
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Error: unexpected symbol in "int main"
Execution halted
https://ideone.com/ZgzgHo
language:
R (R 3.5.2)
created:
15 days ago
visibility:
public

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