Hi,
I would like to evaluate a function f(x,y) taking two vectors as
entries on all pairs of X rows and Y rows, where X and Y are n-by-p
and m-by-p matrices respectively. Of course, I would like to avoid
loops if possible, as the dataset I want to process is quite large.
I was not able to find a combination of outer() and apply() to do
this -- note that I am fairly new to R. Below is a simple example of
what I would like to do -- for illustration purposes only, as I am
not interested in this particular function.
X = matrix(sample(1:3,size=15,replace=TRUE),5,3)
Y = matrix(sample(1:3,size=10,replace=TRUE),5,3)
f = function(x,y) {
max(x/y)
}
A = matrix(0,5,5)
for (i in 1:5) {
for (j in 1:5) {
A[i,j] = f(X[i,],Y[j,])
}
}
Thanks for your help.
Ery Arias-Castro
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