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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 partial_sum = 0;
  10.     int global_sum = 0;
  11.     int numbers[ARRAY_SIZE];
  12.  
  13.     MPI_Init(&argc, &argv);
  14.     MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  15.     MPI_Comm_size(MPI_COMM_WORLD, &size);
  16.  
  17.     // Generate some numbers to sum
  18.     if (rank == 0) {
  19.         for (int i = 0; i < ARRAY_SIZE; i++) {
  20.             numbers[i] = i + 1;
  21.         }
  22.     }
  23.  
  24.     // Scatter the numbers to all processes
  25.     MPI_Scatter(numbers, ARRAY_SIZE/size, MPI_INT, numbers, ARRAY_SIZE/size, MPI_INT, 0, MPI_COMM_WORLD);
  26.  
  27.     // Each process calculates its partial sum
  28.     for (int i = 0; i < ARRAY_SIZE/size; i++) {
  29.         partial_sum += numbers[i];
  30.     }
  31.  
  32.     // Sum up the partial sums from each process
  33.     MPI_Reduce(&partial_sum, &global_sum, 1, MPI_INT, MPI_SUM, 0, MPI_COMM_WORLD);
  34.  
  35.     // Print the global sum
  36.     if (rank == 0) {
  37.         printf("Global sum: %d\n", global_sum);
  38.     }
  39.  
  40.     MPI_Finalize();
  41.     return 0;
  42. }
  43.  
Success #stdin #stdout #stderr 0.27s 40748KB
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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/YBQuTZ
language:
R (R 3.5.2)
created:
17 days ago
visibility:
public

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