pbdMPI (version 0.3-0)

alltoall: All to All

Description

These functions make calls to MPI_Alltoall() and MPI_Alltoallv().

Usage

spmd.alltoall.integer(x.send, x.recv, send.count, recv.count,
                      comm = .pbd_env$SPMD.CT$comm)
spmd.alltoall.double(x.send, x.recv, send.count, recv.count,
                    comm = .pbd_env$SPMD.CT$comm)
spmd.alltoall.raw(x.send, x.recv, send.count, recv.count,
                  comm = .pbd_env$SPMD.CT$comm)
spmd.alltoallv.integer(x.send, x.recv, send.count, recv.count,
                       sdispls, rdispls, comm = .pbd_env$SPMD.CT$comm)
spmd.alltoallv.double(x.send, x.recv, send.count, recv.count,
                      sdispls, rdispls, comm = .pbd_env$SPMD.CT$comm)
spmd.alltoallv.raw(x.send, x.recv, send.count, recv.count,
                   sdispls, rdispls, comm = .pbd_env$SPMD.CT$comm)

Arguments

x.send

an object to send.

x.recv

an object to receive

send.count

send counter

recv.count

recv counter

sdispls

send dis pls

rdispls

recv dis pls

comm

a communicator number.

Value

• These are very low level functions. Use with cautions. Neigher S4 method nor long vector is supported.

Details

These are very low level functions. Use with cautions. Neigher S4 method nor long vector is supported.

References

Programming with Big Data in R Website: http://r-pbd.org/

See Also

allgather(), allgatherv().

Examples

### Save code in a file "demo.r" and run with 2 processors by
### SHELL> mpiexec -np 2 Rscript --vanilla [...].r

### Initial.
suppressMessages(library(pbdMPI, quietly = TRUE))
init()
.comm.size <- comm.size()
.comm.rank <- comm.rank()

### Examples.
n <- as.integer(2)
x <- 1:(.comm.size * n)
comm.cat("Original x:\n", quiet = TRUE)
comm.print(x, all.rank = TRUE)

x <- as.integer(x)
y <- spmd.alltoall.integer(x, integer(length(x)), n, n)
comm.cat("\nAlltoall y:\n", quiet = TRUE)
comm.print(y, all.rank = TRUE)

### Finish.
finalize()