xx_comm_allpairs: Global All Pairs

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

Global All Pairs

Description

This function provide global all pairs.

Usage

comm.allpairs(N, diag = FALSE, symmetric = TRUE,
              comm = .pbd_env$SPMD.CT$comm)

Arguments

N	number of elements for matching, (i, j) for all 1 <= i,j <= N.
diag	if matching the same elements, (i, i) for all i.
symmetric	if matching upper triangular elements. TRUE for i >= j only, otherwise for all (i, j).
comm	a communicator number.

Details

The function generates all combinations of N elements.

Value

The function returns a gbd matrix in row blocks with 2 columns named i and j. The number of rows is dependent on the options diag and symmetric. If diag = TRUE and symmetric = FALSE, then this case has the maximum number of rows, N^2.

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/

See Also

comm.dist().

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))

### Examples.
id.matrix <- comm.allpairs(comm.size() + 1)
comm.print(id.matrix, all.rank = TRUE)

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

## End(Not run)

pbdMPI documentation built on Sept. 10, 2023, 5:06 p.m.