MPI_Recv

Arguments

rank

The rank. TODO

tag

The tag. TODO

comm=mpi_comm

If the optional argument "comm" is given, this function will use the MPI communicator created by MPI_Create_comm. If not, the default MPI_COMM_WORLD is used.

res

The value received from MPI_Send. If the optional argument "comm" is given, all nodes which are not in the communicator will return empty matrix.

Description

Receive a variable from a specified node. The value is usually sent by the function MPI_Send.

Technical implementation

For more information on the implementation of Scilab/MPI, please see Technical details about the implementation

Examples

MPI_Init();
rnk = MPI_Comm_rank();
sizeNodes = MPI_Comm_size();

SLV = rnk;        // handy shortcuts, master is rank 0
Master = ~ SLV;   // slaves are all other
tag = 0;
if Master
    // The master node
    for slaveId = 1:sizeNodes-1
        // Send data to the slaves
        value = rand(100,100) + rand(100,100) * %i;
        MPI_Send(value, slaveId);
    end

    for slaveId = 1:sizeNodes-1
        valueBack = MPI_Recv(slaveId, tag);
        // Check that the slaves gaves us what we expected
        assert_checkequal(valueBack,value + 1);
    end
else
    // The slaves
    rankSource = 0;
    // Receive the information from the master
    value = MPI_Recv(rankSource);
    // Increment all the values by one
    value = value + 1;
    // Send back to the master
    MPI_Send(value, 0);
end

MPI_Finalize();

See also

• MPI_Send — Send data from a node to another