Synergy User Manual and Tutorial. - THE CORE MEMORY

Synergy User Manual and Tutorial
MPI_Init(&argc, &argv);
where argc is the number of arguments and argv is a vector of strings, both of which
should be taken as command line arguments because the same program will be used for
both the master and worker processes in the example application. After initialization, a
program must determine its rank by calling MPI_Comm_rank(), designated by process
number, to determine if it is the master or a worker process. The master will be process
number 0. The function call is:
MPI_Comm_rank(MPI_Comm comm, int* rank);
where comm is a communicator and is defined in MPI’s libraries and rank is a reference
pointer to an integer to hold this process’ rank. It may also be necessary for an
application to determine the number of currently running processes. The
MPI_Comm_size() function returns this number. The function call is:
MPI_Comm_size(MPI_Comm comm, int* size);
where comm is a communicator and is defined in MPI’s libraries and size is a reference
pointer to an integer to hold the number processes. To send a message to another process
the MPI_Send() function is used as such:
MPI_Send(void* msg, strlen(msg)+1, MPI_Datatype type, int dest, int tag,
MPI_Comm comm);
where msg is a message buffer, strlen(msg)+1 sets the length of the message and its null
terminal, type is the data type of the message as defined by MPI’s libraries, dest is an
integer holding the process number of the destination, tag is an integer holding the
message tag, and comm is a communicator and is defined in MPI’s libraries. This is a
blocking send and will wait for the destination to receive the message before executing
further instructions. To receive a message the MPI_Recv() function is used as such:
MPI_Recv(void* msg, int size, MPI_Datatype type, int source, int tag, MPI_Comm
comm, MPI_Status* status)
where msg is a message buffer, is an integer holding the size actual size of the receiving
buffer, type is the data type of the message as defined by MPI’s libraries, source is an
integer holding the process number of the source, tag is an integer holding the message
tag, comm is a communicator and is defined in MPI’s libraries, and status is the data
about the receive operation. To end an MPI application session the MPI_Finalize()
function is called:
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