Generate a iterator along chunks of a vector

Generate a iterator along chunks of a vector

Usage

iterchunks(x, nchunks)

Arguments

x

A vector.

nchunks

Number of chunks.

Examples

if (FALSE) {
library(BiocParallel)
x <- 1:100
BPPARAM <- bpparam()
bpprogressbar(BPPARAM) <- TRUE
bpworkers(BPPARAM) <- 10
slow_fun <- function(x) {
  out <- NULL
  for (i in seq_along(x)) {
    Sys.sleep(0.5)
    out[[i]] <- x[[i]] + 3
  }
  return(out)
}
system.time({
  res0 <- lapply(x, FUN = slow_fun)
})
unlist(res0, recursive = FALSE, use.names = FALSE)[71:73]
system.time({
  res1 <- bplapply(x, FUN = slow_fun, BPPARAM = BPPARAM)
})
unlist(res1, recursive = FALSE, use.names = FALSE)[71:73]
system.time({
  res2 <- bplapply(tochunks(x, nchunks = bpworkers(BPPARAM)), FUN = slow_fun, BPPARAM = BPPARAM)
})
unlist(res2, recursive = FALSE, use.names = FALSE)[71:73]
system.time({
  res3 <- bpiterate(ITER = iterchunks(x, nchunks = bpworkers(BPPARAM)), FUN = slow_fun, BPPARAM = BPPARAM)
})
unlist(res3, recursive = FALSE, use.names = FALSE)[71:73]
}