OK. Try this: > library(Matrix) > M <- matrix(c(2, 1, 1, 2), 2); M [,1] [,2] [1,] 2 1 [2,] 1 2
> # log of expm(M) is original matrix M > with(eigen(expm(M)), vectors %*% diag(log(values)) %*% t(vectors)) [,1] [,2] [1,] 2 1 [2,] 1 2 On Sat, Sep 26, 2009 at 6:24 PM, Charles C. Berry <cbe...@tajo.ucsd.edu> wrote: > On Sat, 26 Sep 2009, Gabor Grothendieck wrote: > >> Try: >> >> expm( - M) > > Mimosa probably meant say 'the inverse function'. > > I do not see one in R. > > Chuck > >> >> On Sat, Sep 26, 2009 at 5:06 PM, Mimosa Zeus <mimosa1...@yahoo.fr> wrote: >>> >>> Dear R users, >>> >>> Does anyone has implemented the inverse of the matrix exponential (expm >>> in the package Matrix)? >>> >>> In Matlab, there're logm and expm, there's only expm in R. >>> Cheers >>> Mimosa >>> >>> >>> >>> [[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. >>> >>> >> >> ______________________________________________ >> 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. >> > > Charles C. Berry (858) 534-2098 > Dept of Family/Preventive > Medicine > E mailto:cbe...@tajo.ucsd.edu UC San Diego > http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901 > > ______________________________________________ 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.