R: Apply Family of Functions

ddmatrix-apply {pbdDMAT}

R Documentation

Apply Family of Functions

Description

Apply a function to the margins of a distributed matrix.

Usage

## S4 method for signature 'ddmatrix'
apply(X, MARGIN, FUN, ..., reduce = FALSE,
  proc.dest = "all")

Arguments

`X`	distributed matrix
`MARGIN`	subscript over which the function will be applied
`FUN`	the function to be applied
`...`	additional arguments to FUN
`reduce`	logical or string. See details
`proc.dest`	Destination process (or 'all') if a reduction occurs

Details

If reduce==TRUE then a global matrix or vector (whichever is more appropriate) will be returned. The argument proc.dest= behaves exactly as in the as.vector() and as.matrix() functions of pbdDMAT. If reduce=FALSE then a distributed matrix is returned. Other acceptable arguments are reduce="matrix" and reduce="vector" which demand global matrix or vector return, respectively. This should generally be slightly more efficient than running apply and then calling as.vector() or as.matrix().

Value

Returns a distributed matrix unless a reduction is requested, then a global matrix/vector is returned.

Examples

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

library(pbdDMAT, quiet = TRUE)
init.grid()

x <- ddmatrix(1:9, 3, bldim=2)

y <- as.vector(apply(x, 1, mean))
comm.print(y)

finalize()

## End(Not run)

[Package pbdDMAT version 0.4-0 Index]