Files
mpi_test/hello_world.cpp
Carl William Pearson b0d2bd24f4 .
2021-06-02 11:08:25 -06:00

41 lines
1.0 KiB
C++

#include <mpi.h>
#include <stdio.h>
int main(int argc, char **argv) {
// Initialize the MPI environment
MPI_Init(&argc, &argv);
// Get the number of processes
int world_size;
MPI_Comm_size(MPI_COMM_WORLD, &world_size);
// Get the rank of the process
int world_rank;
MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);
// Get the name of the processor
char processor_name[MPI_MAX_PROCESSOR_NAME];
int name_len;
MPI_Get_processor_name(processor_name, &name_len);
// Print off a hello world message
printf("Hello world from %s, rank %d out of %d processors\n", processor_name,
world_rank, world_size);
int dst_rank = (world_rank + 1) % world_size;
int src_rank = world_rank - 1;
if (src_rank < 0) {
src_rank = world_size - 1;
}
float val = world_rank;
MPI_Send(&val, 1, MPI_FLOAT, dst_rank, 0, MPI_COMM_WORLD);
MPI_Status stat;
MPI_Recv(&val, 1, MPI_FLOAT, src_rank, 0, MPI_COMM_WORLD, &stat);
printf("rank %d got %f\n", world_rank, val);
// Finalize the MPI environment.
MPI_Finalize();
return 0;
}