From: Achim Zeileis <Achim.Zeileis_at_wu-wien.ac.at>

Date: Thu 10 Mar 2005 - 06:43:09 EST

[1,] 1 1

[2,] 1 1

R> xx

[1] 1 1

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Thu Mar 10 06:50:51 2005

Date: Thu 10 Mar 2005 - 06:43:09 EST

On Wed, 9 Mar 2005 15:24:45 -0400 Owen Buchner wrote:

> I'm attempting to produce a program in which i can multiply a 4x4

*> matrix by a vector. I would like to have this occur 30 times with the
**> product of the matrix and vector replace the original vector, kind of
**> like population growth. I'm having difficulties with the programing
**> aspect and continuously get errors from R. I would appreciate any
**> help.
*

Are you looking for something like this toy example?

Generate a matrix mm and a vector xx:

R> mm <- matrix(rep(1, 4), ncol = 2) R> xx <- rep(1, 2) R> mm [,1] [,2]

[1,] 1 1

[2,] 1 1

R> xx

[1] 1 1

And then pre-multiply 10 times by mm:

R> for(i in 1:10) xx <- mm %*% xx

R> xx

[,1]

[1,] 1024

[2,] 1024

which in this case is of course just 2^10.

hth,

Z

*> Owen Buchner
**>
*

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Thu Mar 10 06:50:51 2005

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