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Datatypes

C

MPI_UINT8_T

Definition

MPI_UINT8_T is an MPI_Datatype that represents an unsigned 1-byte integer type in MPI, it corresponds to an uint8_t in C.

Example

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#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <mpi.h>

/**
 * @brief Illustrate how to communicate an unsigned 1-byte int between 2 MPI
 * processes.
 * @details This application is meant to be run with 2 MPI processes: 1 sender
 * and 1 receiver. The former sends an unsigned 1-byte int to the latter, which
 * prints it.
 **/
int main(int argc, char* argv[])
{
    MPI_Init(&argc, &argv);

    // Check that 2 MPI processes are used.
    int size;
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    if(size != 2)
    {
        printf("This application is meant to be run with 2 MPI processes.\n");
        MPI_Abort(MPI_COMM_WORLD, EXIT_FAILURE);
    }

    // Get my rank and do the corresponding job.
    enum role_ranks { SENDER, RECEIVER };
    int my_rank;
    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
    switch(my_rank)
    {
        case SENDER:
        {
            // Send the int
            uint8_t intToSend = 123;
            printf("[MPI process %d] I send unsigned int: %u.\n", my_rank, intToSend);
            MPI_Ssend(&intToSend, 1, MPI_UINT8_T, RECEIVER, 0, MPI_COMM_WORLD);
            break;
        }
        case RECEIVER:
        {
            // Receive the int
            uint8_t intReceived;
            MPI_Recv(&intReceived, 1, MPI_UINT8_T, SENDER, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
            printf("[MPI process %d] I received unsigned int: %u.\n", my_rank, intReceived);
            break;
        }
    }

    MPI_Finalize();

    return EXIT_SUCCESS;
}

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

/**
 * @brief Illustrate how to communicate an array of unsigned 1-byte ints between
 * 2 MPI processes.
 * @details This application is meant to be run with 2 MPI processes: 1 sender
 * and 1 receiver. The former sends an array of unsigned 1-byte ints to the
 * latter, which prints it.
 **/
int main(int argc, char* argv[])
{
    MPI_Init(&argc, &argv);

    // Check that 2 MPI processes are used.
    int size;
    MPI_Comm_size(MPI_COMM_WORLD, &size);
    if(size != 2)
    {
        printf("This application is meant to be run with 2 MPI processes.\n");
        MPI_Abort(MPI_COMM_WORLD, EXIT_FAILURE);
    }

    // Get my rank and do the corresponding job.
    enum role_ranks { SENDER, RECEIVER };
    int my_rank;
    MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
    switch(my_rank)
    {
        case SENDER:
        {
            // Send the ints
            uint8_t intsToSend[2] = { 50, 100 };
            printf("[MPI process %d] I send unsigned ints: %d and %d.\n", my_rank, intsToSend[0], intsToSend[1]);
            MPI_Ssend(intsToSend, 2, MPI_UINT8_T, RECEIVER, 0, MPI_COMM_WORLD);
            break;
        }
        case RECEIVER:
        {
            // Receive the ints
            uint8_t intsReceived[2];
            MPI_Recv(intsReceived, 2, MPI_UINT8_T, SENDER, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
            printf("[MPI process %d] I received unsigned ints: %d and %d.\n", my_rank, intsReceived[0], intsReceived[1]);
            break;
        }
    }

    MPI_Finalize();

    return EXIT_SUCCESS;
}