In privefl/bigstatsr: Statistical Tools for Filebacked Big Matrices

knitr::opts_chunk$set(echo = TRUE)
unlink(list.files(tempdir(), pattern = "\\.bk$", full.names = TRUE))
options(width = 110)

library(bigstatsr)
library(foreach)

N <- M <- 2000
x4 <- matrix(round(rnorm(N * M, 100, 10)), N)
x3 <- x2 <- x1 <- x4
storage.mode(x1) <- "raw"
storage.mode(x2) <- "logical"
storage.mode(x3) <- "integer"

X5 <- big_copy(x4, type = "double")
X4 <- big_copy(x4, type = "float")
X3 <- big_copy(x4, type = "integer")
X2 <- big_copy(x4, type = "unsigned short")
X1 <- big_copy(x4, type = "unsigned char")

options(bigstatsr.downcast.warning = FALSE)
foreach(X = list(X1, X2, X3, X4, X5)) %:% 
  foreach(x = list(x1, x2, x3, x4), .combine = "c") %do% {
    tmp <- microbenchmark::microbenchmark(X[] <- x)
    round(median(tmp$time) / 1e6)
  }

options(bigstatsr.downcast.warning = TRUE)
foreach(X = list(X1, X2, X3, X4, X5)) %:% 
  foreach(x = list(x1, x2, x3, x4), .combine = "c") %do% {
    tmp <- microbenchmark::microbenchmark(X[] <- x)
    round(median(tmp$time) / 1e6)
  }

library(bigmemory)

Y5 <- as.big.matrix(x4, type = "double")
Y4 <- as.big.matrix(x4, type = "float")
Y3 <- as.big.matrix(x4, type = "integer")
Y2 <- as.big.matrix(x4, type = "short")
Y1 <- as.big.matrix(x4, type = "char")

foreach(X = list(Y1, Y2, Y3, Y4, Y5)) %:% 
  foreach(x = list(x1, x2, x3, x4), .combine = "c") %do% {
    tmp <- microbenchmark::microbenchmark(X[] <- x, times = 10)
    round(median(tmp$time) / 1e6)
  }