Displaying 1 result from an estimated 1 matches for "nrowz".
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nrow
2011 Sep 29
1
efficient coding with foreach and bigmemory
...stem.time(look <- foreach(i=1:5e4, .combine=c) %dopar% rnorm(1))
user system elapsed
90.06 0.03 91.20
=====
library(bigmemory)
library(foreach)
# small data frame that instructs how to fill matrix
info <- data.frame(p=c(0.3, 0.5, 0.2), a1=c(100, 200, 80), a2=c(120, 300,
150))
nrowz <- dim(info)[1]
# example with small matrix
n <- 50
end.i <- cumsum(n*info$p)
start.i <- c(0, end.i[-nrowz]) + 1
m <- matrix(NA, nrow=n, ncol=2)
for(i in 1:nrowz) {
m[start.i[i]:end.i[i], 1] <- runif(n*info$p[i], info$a1[i],
info$a2[i])
m[start.i[i]:end.i[i], 2]...