[R] Creating a matrix with an unknown variable
Blaser Nello
nblaser at ispm.unibe.ch
Wed Jun 26 18:02:56 CEST 2013
You have to define a function. For instance:
Afct <- function(delta){
D <- c(-1, -2/3, -1/3, 0, 1/3, 2/3, 1)
Dmat <- matrix(D, nrow=7, ncol=7)
Smat <- Dmat-t(Dmat)
A <- exp(-(Smat/delta)^2)
return(A)
}
Afct(2)
Also try to avoid loops...
Best,
Nello
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On Behalf Of Jennifer Tickner
Sent: Mittwoch, 26. Juni 2013 10:18
To: r-help at r-project.org
Subject: [R] Creating a matrix with an unknown variable
Hi all
I'm trying to create a matrix, A, with an unknown variable delta. The
code I have so far is:
D<-c(-1, -2/3, -1/3, 0, 1/3, 2/3, 1)
A<-matrix(NA,nrow=7,ncol=7)
for (i in 1:7)
{
for (j in 1:7)
{
A[i,j]<-exp(-((D[i]-D[j])/delta)^2)
}
}
Of course, R comes up with an error message because delta is not yet
defined, but works if I plug in a value for delta. However, I want R to
use the term delta in the matrix A, because I'm trying to estimate delta
in another equation that is written in terms of A. Can anyone help?
Many thanks
Jen
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