Create a matrix with increment and element with zero subscript
On Oct 24, 2011, at 7:23 PM, Md Desa, Zairul Nor Deana Binti wrote:
Hello,
Does anyone knows how to deal with zero subscript in R. I have this
code:
for (i in 1:nitems){
+ for (j in 1:ncat-1) {
+ draw<-matrix(rnorm(nitems*(ncat-1),seed1,seed2),nitems,
(ncat-1))
+ d<-( sigma_d*draw ) + mu_d
+ draw<-matrix(rtnorm((nitems*(ncat-1)),mean = seed1, sd =
seed2, lower = .1, upper = 1.5),nitems,(ncat-1))
+ d<-(sigma_d*draw) + mu_d
+ write.matrix(cbind(b.i0,d), file = "F:/KU/MIRT group/
MIMIC-DIF/R/cpprcode/b0d.dat", sep = " ")
+ b[i,j]<-b[i,j-1]+d[i,j]
+ }
+ }
The error as following:
Error in b[i, j ] <- b[i, j - 1] + d[i, j] :
replacement has length zero
I would like to to have a matrix where the first column takes from
initial pre-assigned value (b[i,0]+d1), the second column is
additive from the first column and a constant d2 that is (b(i,1)=b(i,
0)+d1+d2, and so forth. Is there any way that R can read subscript
of zero?
I don't. (I seem to remember the Matrix package allows such shenanigans.) Why don't you instead augment b[,] with a top column of initial values, using rbind() and then iterate from 2:(ncat-2). (Do note the parentheses and if you do not know why, then consult ?Syntax for operatr precendence.)
David Winsemius, MD West Hartford, CT