Does this do what you want?
nr.of.columns <- 4
myconstant <- 27.5
mymatrix <- matrix(myconstant, nrow=5, ncol=nr.of.columns)
mymatrix[,1] <- 1:5
t(apply(mymatrix, 1, function(x) cumprod(x)))
__________________________________________________________
James Holtman "What is the problem you are trying to solve?"
Executive Technical Consultant -- Office of Technology, Convergys
[EMAIL PROTECTED]
+1 (513) 723-2929
"Rau, Roland"
<[EMAIL PROTECTED]> To:
<r-help@stat.math.ethz.ch>
Sent by: cc:
[EMAIL PROTECTED] Subject: [R] Avoiding a Loop?
ath.ethz.ch
01/21/2005 07:31
Dear R-Helpers,
I have a matrix where the first column is known. The second column is
the result of multiplying this first column with a constant "const". The
third column is the result of multiplying the second column with
"const".....
So far, I did it like this (as a simplified example):
nr.of.columns <- 4
myconstant <- 27.5
mymatrix <- matrix(numeric(0), nrow=5, ncol=nr.of.columns)
mymatrix[,1] <- 1:5
for (i in 2:nr.of.columns) {
mymatrix[,i] <- myconstant * mymatrix[,i-1]
}
Can anyone give me some advice whether it is possible to avoid this loop
(and if yes: how)?
Any suggestions are welcome!
Thanks,
Roland
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