cc_comm: Communicator Functions

In pbdMPI: R Interface to MPI for HPC Clusters (Programming with Big Data Project)

Communicator Functions

Description

The functions provide controls to communicators.

Usage

barrier(comm = .pbd_env$SPMD.CT$comm)
comm.is.null(comm = .pbd_env$SPMD.CT$comm)
comm.rank(comm = .pbd_env$SPMD.CT$comm)
comm.localrank(comm = .pbd_env$SPMD.CT$comm)
comm.size(comm = .pbd_env$SPMD.CT$comm)
comm.dup(comm, newcomm)
comm.free(comm = .pbd_env$SPMD.CT$comm)
init(set.seed = TRUE)
finalize(mpi.finalize = .pbd_env$SPMD.CT$mpi.finalize)
is.finalized()

comm.abort(errorcode = 1, comm = .pbd_env$SPMD.CT$comm)
comm.split(comm = .pbd_env$SPMD.CT$comm, color = 0L, key = 0L,
           newcomm = .pbd_env$SPMD.CT$newcomm)
comm.disconnect(comm = .pbd_env$SPMD.CT$comm)
comm.connect(port.name, info = .pbd_env$SPMD.CT$info,
             rank.root = .pbd_env$SPMD.CT$rank.root,
             comm = .pbd_env$SPMD.CT$comm,
             newcomm = .pbd_env$SPMD.CT$newcomm)
comm.accept(port.name, info = .pbd_env$SPMD.CT$info,
            rank.root = .pbd_env$SPMD.CT$rank.root,
            comm = .pbd_env$SPMD.CT$comm,
            newcomm = .pbd_env$SPMD.CT$newcomm)

port.open(info = .pbd_env$SPMD.CT$info)
port.close(port.name)
serv.publish(port.name, serv.name = .pbd_env$SPMD.CT$serv.name,
             info = .pbd_env$SPMD.CT$info)
serv.unpublish(port.name, serv.name = .pbd_env$SPMD.CT$serv.name,
               info = .pbd_env$SPMD.CT$info)
serv.lookup(serv.name = .pbd_env$SPMD.CT$serv.name,
            info = .pbd_env$SPMD.CT$info)

intercomm.merge(intercomm = .pbd_env$SPMD.CT$intercomm,
                high = 0L, comm = .pbd_env$SPMD.CT$comm)
intercomm.create(local.comm = .pbd_env$SPMD.CT$comm,
                 local.leader = .pbd_env$SPMD.CT$rank.source,
                 peer.comm = .pbd_env$SPMD.CT$intercomm,
                 remote.leader = .pbd_env$SPMD.CT$rank.dest,
                 tag = .pbd_env$SPMD.CT$tag, 
                 newintercomm = .pbd_env$SPMD.CT$newcomm)

comm.c2f(comm = .pbd_env$SPMD.CT$comm)

Arguments

comm	a communicator number.
mpi.finalize	if MPI should be shutdown.
set.seed	if a random seed preset.
port.name	a port name with default maximum length 1024 characters for OpenMPI.
info	a info number.
rank.root	a root rank.
newcomm	a new communicator number.
color	control of subset assignment.
key	control of rank assigment.
serv.name	a service name.
errorcode	an error code to abort MPI.
intercomm	a intercommunicator number.
high	used to order the groups within comm.
local.comm	a local communicator number.
local.leader	the leader number of local communicator.
peer.comm	a peer communicator number.
remote.leader	the remote leader number of peer communicator.
newintercomm	a new intercommunicator number.
tag	a tag number.

Details

Another functions are direct calls to MPI library.

barrier() blocks all processors until everyone call this.

comm.is.null() returns -1 if the array of communicators is not allocated, i.e. init() is not called yet. It returns 1 if the communicator is not initialized, i.e. NULL. It returns 0 if the communicator is initialized.

comm.rank() returns the processor's rank for the given comm.

comm.size() returns the total processes for the given comm.

comm.dup() duplicate a newcomm from comm.

comm.free() free a comm.

init() initializes a MPI world, and set two global variables .comm.size and .comm.rank in .GlobalEnv. A random seed will be preset by default (Sys.getpid() + Sys.time()) to the package rlecuyer.

finalize() frees memory and finishes a MPI world if mpi.finalize = TRUE. is.finalized() checks if MPI is already finalized.

comm.abort() aborts MPI.

comm.split() create a newcomm by color and key.

comm.disconnect() frees a comm.

comm.connect() connects a newcomm.

comm.accept() accepts a newcomm.

port.open() opens a port and returns the port name.

port.close() closes a port by name.

serv.publish() publishs a service via port.name.

serv.unpublish() unpublishs a service via port.name.

serv.lookup() lookup the serv.name and returns the port name.

intercomm.merge() merges the intercomm to intracommunicator.

intercomm.create() creates a new intercomm from two peer intracommunicators.

comm.c2f() returns an integer for Fortran MPI support.

Value

Most function return an invisible state of MPI call.

Author(s)

Wei-Chen Chen [e-mail], George Ostrouchov, Drew Schmidt, Pragneshkumar Patel, and Hao Yu.

References

Programming with Big Data in R Website: https://pbdr.org/

Examples

## Not run: 
### Save code in a file "demo.r" and run with 2 processors by
### SHELL> mpiexec -np 2 Rscript demo.r

spmd.code <- "
### Initialize
suppressMessages(library(pbdMPI, quietly = TRUE))
.comm.size <- comm.size()
.comm.rank <- comm.rank()

### Examples .
comm.print(.comm.size)
comm.print(.comm.rank, all.rank = TRUE)
comm.print(comm.rank(), rank.print = 1)
comm.print(comm.c2f())

### Finish.
finalize()
"
# execmpi(spmd.code, nranks = 2L)

## End(Not run)

pbdMPI documentation built on Sept. 18, 2024, 9:07 a.m.