On Fri, Nov 4, 2011 at 2:37 PM, David Winsemius <dwinsemius at comcast.net> wrote: > > The 12th (matrix) root of M: e^( 1/n * log(M) ) > >> require(Matrix) >> M1.12 <- expm( (1/12)*logm(M) ) I like this - haven't thought of the matrix algebra functions in Matrix. Thanks, Peter