Hi Matt, Petr gave you one possibility. If you are looking for more matrix operations see:
?"%*%" # the inner product of the matrices ?"%o%" # the outer product of the matrices ?"(" # for parentheses to help order things require(MASS) # load the package MASS ?ginv # for the generalized inverse of a matrix For things like constants which you just want treated normally, use the regular multiplication operator, "*", not the matrix one. HTH, Josh On Mon, Apr 11, 2011 at 12:43 AM, matthew.r.robin...@sheffield.ac.uk <matthew.r.robin...@sheffield.ac.uk> wrote: > Hi all, > > I have two matrices: > > G<-matrix(c(2.0, 0.5, 0.5, 0.5, 2.0, 0.5, 0.5, 0.5,2.0),3,3) > P<-matrix(c(1.0, 0.5, 0.5, 0.5, 1.0, 0.5, 0.5, 0.5,1.0),3,3) > > and I want to run this equation to get a new matrix F: > > F = [P+2G]^-1/2 P [P+2G]^-1/2 > > Could someone please tell me how to code this in R? > > Many thanks in advance for your time. > > Best wishes, > Matt > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. -- Joshua Wiley Ph.D. Student, Health Psychology University of California, Los Angeles http://www.joshuawiley.com/ ______________________________________________ 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.