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  1. #include <mpi.h>
  2. #include <iostream>
  3.  
  4. int main(int argc, char** argv) {
  5.     MPI_Init(&argc, &argv);
  6.  
  7.     int rank, size;
  8.     MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  9.     MPI_Comm_size(MPI_COMM_WORLD, &size);
  10.  
  11.     int message;
  12.     MPI_Status status;
  13.  
  14.     if (rank == 0) {
  15.         // Initialize message to be sent
  16.         message = rank;
  17.  
  18.         // Send message to the next process in a ring
  19.         MPI_Send(&message, 1, MPI_INT, (rank + 1) % size, 0, MPI_COMM_WORLD);
  20.  
  21.         // Receive message from the last process in a ring
  22.         MPI_Recv(&message, 1, MPI_INT, size - 1, 0, MPI_COMM_WORLD, &status);
  23.  
  24.         // Output the received message
  25.         std::cout << "Process " << rank << " received message: " << message << std::endl;
  26.     } else {
  27.         // Receive message from the previous process in a ring
  28.         MPI_Recv(&message, 1, MPI_INT, rank - 1, 0, MPI_COMM_WORLD, &status);
  29.  
  30.         // Increment message
  31.         message = (message + 1) % size;
  32.  
  33.         // Send message to the next process in a ring
  34.         MPI_Send(&message, 1, MPI_INT, (rank + 1) % size, 0, MPI_COMM_WORLD);
  35.  
  36.         // Output the received message
  37.         std::cout << "Process " << rank << " received message: " << message << std::endl;
  38.     }
  39.  
  40.     MPI_Finalize();
  41.     return 0;
  42. }
  43.  
Success #stdin #stdout #stderr 0.33s 40312KB
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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/zXMPPb
language:
R (R 3.5.2)
created:
10 days ago
visibility:
public

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