xx_comm_base: Global Base Functions

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

Global Base Functions

Description

These functions are global base functions applying on distributed data for all ranks.

Usage

comm.length(x, comm = .pbd_env$SPMD.CT$comm)
comm.sum(..., na.rm = TRUE, comm = .pbd_env$SPMD.CT$comm)
comm.mean(x, na.rm = TRUE, comm = .pbd_env$SPMD.CT$comm)
comm.var(x, na.rm = TRUE, comm = .pbd_env$SPMD.CT$comm)
comm.sd(x, na.rm = TRUE, comm = .pbd_env$SPMD.CT$comm)

Arguments

x	a vector.
...	as in sum().
na.rm	logical, if remove NA and NaN.
comm	a communicator number.

Details

These functions will apply globally length(), sum(), mean(), var(), and sd().

Value

The global values are returned to all ranks.

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))

if(comm.size() != 2){
  comm.cat(\"2 processors are requried.\n\", quiet = TRUE)
  finalize()
}

### Examples.
a <- 1:(comm.rank() + 1)

b <- comm.length(a)
comm.print(b)
b <- comm.sum(a)
comm.print(b)
b <- comm.mean(a)
comm.print(b)
b <- comm.var(a)
comm.print(b)
b <- comm.sd(a)
comm.print(b)

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

## End(Not run)

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