Intel® MPI Library Developer Guide for Linux* OS

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ID 768728
Date 11/07/2023
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Document Table of Contents
Document Table of Contents x
Intel® MPI Library Developer Guide for Linux* OS
Intel® MPI Library Developer Guide for Linux* OS x
Introduction Installation and Prerequisites Compiling and Linking Running Applications Debugging Applications Analysis and Tuning Troubleshooting Additional Supported Features Examples Notices and Disclaimers
Introduction x
Introducing Intel® MPI Library Conventions and Symbols Related Information
Installation and Prerequisites x
Installation Prerequisite Steps
Compiling and Linking x
Compiling an MPI Program Compilers Support ILP64 Support
Running Applications x
Running Intel® MPI Library in Containers Selecting a Library Configuration Running an MPI Program Running an MPI/OpenMP* Program MPMD Launch Mode Fabrics Control Job Schedulers Support Controlling Process Placement Java* MPI Applications Support
Running Intel® MPI Library in Containers x
Build a Singularity* Container for an MPI Application Run the Application with a Container
Fabrics Control x
Selecting Fabrics Libfabric* Support OFI* Providers Support
Debugging Applications x
Debugging Using -gtool for Debugging
Analysis and Tuning x
Displaying MPI Debug Information Tracing Applications Interoperability with Other Tools Through -gtool MPI Tuning
Troubleshooting x
Error Message: Bad Termination Error Message: No such file or Directory Error Message: Permission Denied Error Message: Fatal Error Error Message: Bad File Descriptor Error Message: Too Many Open Files Problem: High Memory Consumption Readings Problem: MPI Application Hangs Problem: Password Required Problem: Cannot Execute Binary File Problem: MPI limitation for Docker*
Additional Supported Features x
Asynchronous Progress Control Multiple Endpoints Support
Multiple Endpoints Support x
MPI_THREAD_SPLIT Programming Model Threading Runtimes Support Program Examples Code Change Guide
Examples x
async_progress_sample.c thread_split.cpp thread_split_omp_for.c thread_split_omp_task.c See Also thread_split_pthreads.c
Intel® MPI Library Developer Guide for Linux* OS

thread_split_omp_task.c

#include <mpi.h>
#include <omp.h>
#define n 2
MPI_Comm split_comm[n];
int main()
{
    MPI_Info info;
    int i, provided;
    char s[16];
    MPI_Init_thread(NULL, NULL, MPI_THREAD_MULTIPLE, &provided);
    MPI_Info_create(&info);
    for (i = 0; i < n; i++) {
        MPI_Comm_dup(MPI_COMM_WORLD, &split_comm[i]);
        sprintf(s, "%d", i);
        MPI_Info_set(info, "thread_id", s);
        MPI_Comm_set_info(split_comm[i], info);
    }
#pragma omp parallel num_threads(n)
    {
#pragma omp task
        {
            int j = 1;
            MPI_Allreduce(MPI_IN_PLACE, &j, 1, MPI_INT, MPI_SUM, split_comm[1]);
            printf("OMP thread %d, logical thread %d: allreduce returned %d\n",
                   omp_get_thread_num(), 1, j);
        }
#pragma omp task
        {
            int j = 0;
            MPI_Allreduce(MPI_IN_PLACE, &j, 1, MPI_INT, MPI_SUM, split_comm[0]);
            printf("OMP thread %d, logical thread %d: allreduce returned %d\n",
                   omp_get_thread_num(), 0, j);
        }
    }
    MPI_Info_free(&info);
    MPI_Finalize();
}
Parent topic: Examples
Level Two Title