pbdDMAT (version 0.2-3)

Insert: Directly Insert Into Distributed Matrix Submatrix Slot

Description

Allows you to directly replace the submatrix of a distributed matrix.

Usage

x[i, j] <- value
submatrix(x) <- value

Arguments

x

numeric distributed matrix.

i, j

global integer indices.

value

replacement value. Can be a global vector or a ddmatrix.

Value

• Returns a distributed matrix.

Details

[<- allows the user to insert values into a distributed matrix in exactly the same way one would with an ordinary matrix. The indices here are global, meaning that x[i, j] refers to the (i, j)'th element of the "full", global matrix, and not necessarily the (i, j)'th element of the local submatrix.

On the other hand, submatrix<- is different. It is basically syntactic sugar for: x@Data <- newMatrix It does not alter the distributed matrix x's dim or bldim. It does adjust the ldim automatically. However, using this can be dangerous. It is merely provided to give consistent behavior with the submatrix() function.

Examples

# 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()

# don't do this in production code
x <- matrix(1:9, 3)
x <- as.ddmatrix(x)

x[1, ] <- 0
comm.print(submatrix(x), all.rank=T)

finalize()