[R] system is computationally singular: reciprocal condition number
langvince
langv at purdue.edu
Fri Oct 26 01:14:26 CEST 2012
Hi folks,
I know, this is a fairly common question and I am really disappointed that I
could not find a solution.
I am trying to calculate Mahanalobis distances in a data frame, where I have
several hundreds groups and several hundreds of variables.
Whatever I do, however I subset it I get the "system is computationally
singular: reciprocal condition number" error.
I know what it means and I know what should be the problem, but there is no
way this is a singular matrix.
I have uploaded the input file to my ftp:
http://mkk.szie.hu/dep/talt/lv/CentInpDuplNoHeader.txt
It is a tab delimited txt file with no headers.
I tried the StatMatch Mahanalobis function and also this function:
mahal_dist <-function (data, nclass, nvariable) {
dist <- matrix(0, nclass, nclass)
n=0
w <- cov(data)
print(w)
for(i in 1:nclass) {
for(c in 1:nclass){
diffl <- vector(length = nvariable)
for(l in 1:nvariable){
diffl[l]=abs(data[i,l]-data[c,l])
}
### matrixes
print(diffl)
dist[i,c]= (t(diffl))%*%(solve(w))%*%(diffl)
}
n=n+1
print(n)
}
return(dist)
sqrt_dist <- sqrt(dist)
print(sqrt_dist) }
I have a deadline for this project (not a homework:)), and I could always
use this codes, so I thought I will be able to quit the calculations short,
but now I am just lost.
I would really appreciate any help.
Thanks for any help
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