The other solutions offered are perfectly workable. Here is a strategy
that is generalizable to other matrix designs (and on checking the
source of upper.tri and lower.tri, it's not surprising that they use
precisely the same strategy):
n <- 9
dm <- matrix(0, nrow=n, ncol=n)
dm[col(dm) >=
Of Dale Steele
> Sent: Wednesday, February 11, 2009 4:23 PM
> To: R help
> Subject: [R] Efficent way to create an nxn upper triangular
> matrix of one's
>
> The code below create an nxn upper triangular matrix of
> one's. I'm stuck on finding a more efficie
Dear Dale,
Here is one way, probably not the best:
n<-9
temp<-matrix(1,ncol=n,nrow=n)
temp[lower.tri(temp)] <- 0
temp
HTH,
Jorge
On Wed, Feb 11, 2009 at 4:22 PM, Dale Steele wrote:
> The code below create an nxn upper triangular matrix of one's. I'm
> stuck on finding a more efficient vector
Try
x <- diag(n)
x[upper.tri(x)] <- 1
On Wed, Feb 11, 2009 at 1:22 PM, Dale Steele wrote:
> The code below create an nxn upper triangular matrix of one's. I'm
> stuck on finding a more efficient vectorized way - Thanks. --Dale
>
> n <- 9
> data <- matrix(data=NA, nrow=n, ncol=n)
> data
> for (
The code below create an nxn upper triangular matrix of one's. I'm
stuck on finding a more efficient vectorized way - Thanks. --Dale
n <- 9
data <- matrix(data=NA, nrow=n, ncol=n)
data
for (i in 1:n) {
data[,i] <- c(rep(1,i), rep(0,n-i))
}
data
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