Your code is doing too many needless things.
The following takes about one second on my slow Vista laptop.
n <- 500
mat <- matrix(1:(n*n), n)
v <- n:1
z <- 2*1:(n/2)
w <- c(z, rev(z))
for(i in seq_len(n)){
for(j in seq_len(n)){
if(v[j] + w[i] <= n)(mat[i,j] <- NA)
}
}
rownames(mat) <- v
c
> -Original Message-
> From: r-help-boun...@r-project.org
> [mailto:r-help-boun...@r-project.org] On Behalf Of Etienne Stockhausen
> Sent: Tuesday, January 12, 2010 10:59 AM
> To: r-help@r-project.org
> Subject: [R] Making routine faster by using apply instead of
Hey everybody,
I have a small problem with a routine, which prepares some data for
plotting.
I've made a small example:
c=10
mat=data.frame(matrix(1:(c*c),c,c))
row.names(mat)=seq(c,1,length=c)
names(mat)=c(seq(2,c,length=c/2),seq(c,2,length=c/2))
v=as.numeric(row.names(mat))
w
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