MPI Number of processors?

Question

Below is my MPI code, which I run on the core of the i7 processor (quad-core processor), but the problem is that it shows that it runs under 1 processor processor, which should be 4.

int main(int argc, char *argv[]) { int rank, size; MPI_Init(&argc, &argv); MPI_Comm_rank(MPI_COMM_WORLD, &rank); MPI_Comm_size(MPI_COMM_WORLD, &size); printf("Hello world! I am %d of %d\n", rank, size); MPI_Finalize(); return 0; } 

I was wondering if there is a problem with the MPI library or something else?

Here is the result that shows me:

 Hello world! I am 0 of 1 

Additional Information: Windows 7 - Professional x64

Answer 1

Prima facie it looks like you are running the program directly. Have you tried using mpiexec -n 2 or -n 4 ?