> -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On > Behalf Of cindy Guo > Sent: Monday, August 10, 2009 2:32 PM > To: r-help@r-project.org > Subject: [R] matrix power > > Hi, All, > > If I have a symmetric matrix, how can I get the negative square root of the > matrx, ie. X^(-1/2) ? > > Thanks, > > Cindy >
Cindy, Just to be sure we are all on the same page. Are saying you have a matrix X, and you want to find the a matrix A such that X = A %*% A And you want to then find the matrix inverse of A ? Dan Daniel J. Nordlund Washington State Department of Social and Health Services Planning, Performance, and Accountability Research and Data Analysis Division Olympia, WA 98504-5204 ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.