EVOLUTION-MANAGER

Edit File: matmul2.R

# Less inefficient parallel matrix multiply using custom matrix iterator library(foreach) iblkcol <- function(a, chunks) { n <- ncol(a) i <- 1 nextEl <- function() { if (chunks <= 0 || n <= 0) stop('StopIteration') m <- ceiling(n / chunks) r <- seq(i, length=m) i <<- i + m n <<- n - m chunks <<- chunks - 1 a[,r, drop=FALSE] } obj <- list(nextElem=nextEl) class(obj) <- c('abstractiter', 'iter') obj } # generate the input matrices x <- matrix(rnorm(100), 10) y <- matrix(rnorm(100), 10) # multiply the matrices nw <- getDoParWorkers() cat(sprintf('Running with %d worker(s)\n', nw)) mit <- iblkcol(y, nw) z <- foreach(y=mit, .combine=cbind) %dopar% (x %*% y) # print the results print(z) # check the results print(all.equal(z, x %*% y))