manipulation of list of matrices
Folks, I have a list of correlation matrices of equities, say, and I need to manipulate each matrix: I weight each equity by its median absolute correlation against all the other equities, such that the equity with the least such correlation gets the highest weight. Something like min(over all average correlations) / average correlation of equity So I do the following:
a <- lapply(1:1000, function(n) {b <- matrix(runif(45*45, min = -1, max
= 1), ncol = 45); diag(b) <- 1; b})
I write the following function:
constructCorrelationWeights <- function(rollCorr, FUN = median)
{
corWt <- sapply(rollCorr,
function(corMat)
{
wt <- apply(corMat, 1, function(x) FUN(abs(x)))
min(wt) / wt
})
t(corWt)
}
system.time(corWt <- constructCorrelationWeights(a))
[1] 33.42 18.03 79.55
Is there a more efficient and cleverer way to accomplish this?
Many thanks,
Murali
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