CODEWITHSUNDEEP
c++windowsvisual-studiompibreakpoints
Milan
Milan

Reputation: 75

Why does my MPI application trigger a breakpoint?

I have a simple MPI application that is used to pass values from process 0 to other processes upon entering the desired value but it is triggering a breakpoint on "else".

What am I missing?

#include "stdafx.h"
#include "mpi.h"
#include "stdio.h"
#include "stdlib.h"

int main(int argc, char* argv[])
{
    int rank;
    int value;
    int size;

    MPI_Status status;
    MPI_Init(&argc, &argv);

    MPI_Comm_rank(MPI_COMM_WORLD, &rank);
    MPI_Comm_size(MPI_COMM_WORLD, &size);

    do
    {
        if (rank == 0)
        {
            printf("Enter the value: ");
            scanf_s("%d", &value);
            MPI_Send(&value, 1, MPI_INT, rank + 1, 0, MPI_COMM_WORLD);
        }

        else
        {
            MPI_Recv(&value, 1, MPI_INT, rank - 1, 0, MPI_COMM_WORLD, 
                     &status);
            
            if (rank < size - 1)
                MPI_Send(&value, 1, MPI_INT, rank + 1, 0, MPI_COMM_WORLD);
        }

        printf("Process %d got %d ", rank, value);

    } while (value >= 0);
    
    MPI_Finalize();
    return 0;
}

This is output from debug:

'MPIHelloWorld.exe' (Win32): Loaded 'C:\WINDOWS\SysWOW64\KernelBase.dll'. Cannot find or open the PDB file.

'MPIHelloWorld.exe' (Win32): Loaded 'C:\WINDOWS\SysWOW64\gdi32.dll'. Cannot find or open the PDB file.

'MPIHelloWorld.exe' (Win32): Loaded 'C:\Program Files (x86)\Bonjour\mdnsNSP.dll'. Cannot find or open the PDB file.

MPIHelloWorld.exe has triggered a breakpoint.

MPIHelloWorld.exe has triggered a breakpoint.

The thread 0x3308 has exited with code 0 (0x0).

The thread 0x1dfc has exited with code 0 (0x0).

The thread 0x2e5c has exited with code 0 (0x0).

The program '[4400] MPIHelloWorld.exe' has exited with code 0 (0x0).

UPDATE:

When I press CTRL + 5 I get this error written in my console:

job aborted: [ ranks ] message

[0] fatal error Fatal error in MPI_Send: Invalid rank has value 1 but must be nonnegative and less than 1

Upvotes: 0

Views: 1181

Answers (1)

Milan
Milan

Reputation: 75

Ok, I have finally found an answer!

I couldn't use Cluster Debugger for MPI since I am running Visual Studio 2015 and the problem was that only 1 process was running.

I opened CMD and ran my application using "mpiexec.exe -n 4 myMpiApp.exe" and it worked.

Upvotes: 3

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