MPI_Bcast

--- Broadcasts a message from the process with rank "root" to all other processes of the group.

Input/output Parameter

buffer: starting address of buffer (choice)

count: number of entries in buffer (integer)

datatype: data type of buffer (handle)

root: rank of broadcast root (integer)

comm: communicator (handle)

Algorithm

This function uses a tree-like algorithm to broadcast the message to blocks of processes. A linear algorithm is then used to broadcast the message from the first process in a block to all other processes. MPIR_BCAST_BLOCK_SIZE determines the size of blocks. If this is set to 1, then this function is equivalent to using a pure tree algorithm. If it is set to the size of the group or greater, it is a pure linear algorithm. The value should be adjusted to determine the most efficient value on different machines.

Synopsis


#include "mpi.h"
int MPI_Bcast ( buffer, count, datatype, root, comm )
void             *buffer;
int               count;
MPI_Datatype      datatype;
int               root;
MPI_Comm          comm;

Location: bcast.c