I need to wrap a loop inside a function and am having a small bit of
difficulty getting the results I need. Below is a replicable example.
# define functions
pcm <- function(theta,d,score){
exp(rowSums(outer(theta,d[1:score],'-')))/
apply(exp(apply(outer(theta,d, '-'), 1, cumsum)), 2, sum)
}
foo <- function(theta,items, score){
like.mat <- matrix(numeric(length(items) * length(theta)), ncol =
length(theta))
for(i in 1:length(items)) like.mat[i, ] <- pcm(theta, items[[i]],
score[[i]])
}
# begin example
theta <- c(-1,-.5,0,.5,1)
items <- list(item1 = c(0,1,2), item2 = c(0,1), item3 = c(0,1,2,3,4),
item4 = c(0,1))
score <- c(2,1,3,1)
(foo(theta, items, score))
# R output from function foo
[1] 0.8807971 0.8175745 0.7310586 0.6224593 0.5000000
However, what I am expecting from the function foo is
> like.mat
[,1] [,2] [,3] [,4] [,5]
[1,] 0.118499655 0.17973411 0.25949646 0.34820743 0.4223188
[2,] 0.880797078 0.81757448 0.73105858 0.62245933 0.5000000
[3,] 0.005899109 0.01474683 0.03505661 0.07718843 0.1520072
[4,] 0.880797078 0.81757448 0.73105858 0.62245933 0.5000000
I cannot seem to track down why the function foo is only keeping the
last row of the full matrix I need. Can anyone see where my error is?
Thanks,
Harold
platform i386-pc-mingw32
arch i386
os mingw32
system i386, mingw32
status
major 2
minor 3.0
year 2006
month 04
day 24
svn rev 37909
language R
version.string Version 2.3.0 (2006-04-24)
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