On May 30, 2015, at 8:56 AM, Michelle Morters wrote:
> Hi - I'm trying to generate the (toy) matrix below in R. I get the error
> message shown below (and no matrix!) and I'm unclear as to why - if
> someone could advise as to why, that would be ace. Thank you! Michelle
>
>
> 0.7 0 0.1 0 0.1 0 0 0 0 0
> 0 0
> 0.1 0.7 0.1 0.1 0.1 0.1 0 0 0 0
> 0 0
> 0.1 0.1 0.7 0 0.1 0 0.1 0 0 0
> 0 0
> 0.1 0.1 0.1 0.7 0.1 0.1 0.1 0.1 0 0
> 0 0
> 0.1 0.1 0.1 0.1 0.7 0 0.1 0 0.1 0
> 0 0
> 0 0.1 0.1 0.1 0.1 0.7 0.1 0.1 0.1 0.1
> 0 0
> 0 0 0.1 0.1 0.1 0.1 0.7 0 0.1 0
> 0.1 0
> 0 0 0 0.1 0.1 0.1 0.1 0.7 0.1 0.1
> 0.1 0.1
> 0 0 0 0 0.1 0.1 0.1 0.1 0.7 0
> 0.1 0
> 0 0 0 0 0 0.1 0.1 0.1 0.1 0.7
> 0.1 0.1
> 0 0 0 0 0 0 0.1 0.1 0.1 0.1
> 0.7 0
> 0 0 0 0 0 0 0 0.1 0.1 0.1
> 0.1 0.7
>
>
One can use loopless methods:
cross = 0.1
diag_val = 0.7
n=12
nbe=4
m = matrix(0, nrow=n, ncol=n)
diag(m)=diag_val # probably better not to use 'diag' as name of value.
rm <- row(m); cm <- col(m) # creates indicator matrices of same size
m[abs(rm - cm) < 4 & rm != cm] <- cross # Fill supra- and sub-diagonals.
m[ cm %% 2 == 0 & rm %% 2 == 1 & rm < cm ] = 0
# Zero supra diags in odd rows and in even cols.
#-------------
> m
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
[1,] 0.7 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0
[2,] 0.1 0.7 0.1 0.1 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0
[3,] 0.1 0.1 0.7 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0
[4,] 0.1 0.1 0.1 0.7 0.1 0.1 0.1 0.0 0.0 0.0 0.0 0.0
[5,] 0.0 0.1 0.1 0.1 0.7 0.0 0.1 0.0 0.0 0.0 0.0 0.0
[6,] 0.0 0.0 0.1 0.1 0.1 0.7 0.1 0.1 0.1 0.0 0.0 0.0
[7,] 0.0 0.0 0.0 0.1 0.1 0.1 0.7 0.0 0.1 0.0 0.0 0.0
[8,] 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.7 0.1 0.1 0.1 0.0
[9,] 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.7 0.0 0.1 0.0
[10,] 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.7 0.1 0.1
[11,] 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.7 0.0
[12,] 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.1 0.7
--
David
>
> cross = 0.1
> diag = 0.7
> n=12 # to be changed to n=1:100 once the code below is correct
> nbe=4
> R0=sapply(n,function(x){
> m = matrix(0, nrow=x, ncol=x)
# this would be creating a series of "m" objects at various values of n x n
dimensions and then over-writing them.
> for (i in 1:x)
> {
> for(j in 1:x)
> {
> if (i==j)
> {
> m[i,j] = diag
> }
> else if(j<=i+nbe & j>=i-nbe)
> {
> m[i,j]=cross
> }
> }
> }
> for (i in seq(1,x,2))
> {
> for (j in seq(i+1,i+nbe,2))
> {
> m[i,j]=0
> }
> }
> print(m)
> max(Mod(eigen(m)$value))
> }
> )
> R0
>
> error message: Error in `[<-`(`*tmp*`, i, j, value = 0) : subscript out
> of bounds
>
>
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> [[alternative HTML version deleted]]
>
> ______________________________________________
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
David Winsemius
Alameda, CA, USA
______________________________________________
R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
