On Sun, 12 Nov 2006, YONGWAN CHUN wrote:
I wonder by chance if there is a way to reduce computing time for matrix
addition or subtraction. With a lot of iterations, it would be helpful
to reduce a little amount time.
Yes, by making use of an optimized BLAS: see the R-admin manual. On my
not concerning your subject line, but function crossprod may be useful, too
Matthias
- original message
Subject: Re: [R] Computing time for matrix addition or subtraction
Sent: Mon, 13 Nov 2006
From: Prof Brian Ripley[EMAIL PROTECTED]
On Sun, 12 Nov 2006, YONGWAN CHUN wrote
Hello,
I wonder by chance if there is a way to reduce computing time for matrix
addition or subtraction. With a lot of iterations, it would be helpful to
reduce a little amount time.
Simple example is as below
n - 2000
P - matrix(rnorm(n*n),n,n)
PP - P %*% P
M - diag(n) - P
R - M + t(M) -
This is slightly faster but not by much:
ad - function(m, a) { diag(m) - diag(m) + a; m }
R - ad(P %*% P - t(P) - P, 1)
On 11/12/06, YONGWAN CHUN [EMAIL PROTECTED] wrote:
Hello,
I wonder by chance if there is a way to reduce computing time for matrix
addition or subtraction. With a lot of
