xx_comm_sort: Global Quick Sort for Distributed Vectors or Matrices

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

Global Quick Sort for Distributed Vectors or Matrices

Description

This function globally sorts distributed data for all ranks.

Usage

comm.sort(x, decreasing = FALSE, na.last = NA,
          comm = .pbd_env$SPMD.CT$comm,
          status = .pbd_env$SPMD.CT$status)

Arguments

x	a vector.
decreasing	logical. Should the sort order be increasing or decreasing?
na.last	for controlling the treatment of NAs. If TRUE, missing values in the data are put last; if FALSE, they are put first; if NA, they are removed.
comm	a communicator number.
status	a status number.

Details

The distributed quick sort is implemented for this functions.

Value

The returns are the same size of x but in global sorting order.

Warning

All ranks may not have a NULL x.

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.set.seed(123456, diff = TRUE)
x <- c(rnorm(5 + .comm.rank * 2), NA)
# x <- sample(1:5, 5 + .comm.rank * 2, replace = TRUE)
comm.end.seed()

if(.comm.rank == 1){
  x <- NULL    ### Test for NULL or 0 vector
}

y <- allgather(x)
comm.print(y)

y <- comm.sort(x)
y <- allgather(y)
comm.print(y)

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

## End(Not run)

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