MPI_Wtime（）返回0

Question

我正在Linux上使用openMPI版本4.0.1编译以下代码，并且MPI_Wtime()返回0。我正在使用mpicc -o testCode myfile.c

进行编译。

#include <stdio.h>
#include <time.h>
#include <mpi.h>

int main(int argc, char* argv[])
{

    // Initialize MPI
    MPI_Init(&argc, &argv);

    // printf("%d\n",MPI_UNIVERSE_SIZE);

    // Get the clock precision and start the clock.
    double precision = MPI_Wtick();
    double starttime = MPI_Wtime();

    // Get this processor's rank and the size of the world.
    int rank, size;
    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &size);

    if (rank ==0)
        printf("start time = %g\n", starttime);

    MPI_Finalize();

    return 0;
}