On 16 July 2012 at 23:30, French, Joshua wrote: | I am doing some linear algebra on large matrices in R and receiving the | following error: "allocMatrix: too many elements specified". From what I | understand, the error is caused by the fact that R uses 32-bit ints and not | 64-bit ints for matrix indices, so R doesn't have a way to represent all the | elements in the very large matrix. | | My two questions: | | 1. Armadillo (and presumably RcppArmadillo) will not have this issue since | Armadillo provided support for 64-bit indices as of version 2.4.0. Is there a | way to easily utilize this functionality from within RcppArmadillo?
I need to double check but this may have been a compile-time option you need to enable. In any event ... R indices are still limited so you may not be able to pass these back and forth. | 2. I have found in the past that some of the speeds gains from RcppArmadillo | in comparison to pure R are lost when passing large matrices as arguments. | There will always be overhead when passing arguments (especially large matrix | arguments) to pretty much any function. Are there any tricks to minimize the | overhead when passing a non-sparse matrix argument of say 1,000,000 by 500 from | R to Armadillo? I defer all question concerning sparse matrices to Doug and other users of sparse matrix code. I live mostly in a small-to-medium size dense matrix world. Dirk | Thanks. | -- | Joshua French, Ph.D. | Assistant Professor | Department of Mathematical and Statistical Sciences | University of Colorado Denver | joshua.fre...@ucdenver.edu | http://math.ucdenver.edu/~jfrench/ | Ph: 303-556-6265 Fax: 303-556-8550 | | | ---------------------------------------------------------------------- | _______________________________________________ | Rcpp-devel mailing list | Rcpp-devel@lists.r-forge.r-project.org | https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel -- Dirk Eddelbuettel | e...@debian.org | http://dirk.eddelbuettel.com _______________________________________________ Rcpp-devel mailing list Rcpp-devel@lists.r-forge.r-project.org https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
