Thanks Dirk! That looks interesting! I will check which solution performs better in my application!
Best Simon On Aug 26, 2013, at 1:24 PM, Dirk Eddelbuettel <[email protected]> wrote: > > On 26 August 2013 at 12:19, Simon Zehnder wrote: > | Dear Rcpp::Users and Rcpp::Devels, > | > | I am right now working on a relabeling algorithm where I have a function > | taking a permutation matrix of all permutations of the labels. Inside the > | function the values should be permuted in respect to a row of this > | matrix. In R I would use the following commands: > | > | values <- matrix(rnorm(4), ncol = 2, nrow = 2, byrow = TRUE) > | perm <- as.matrix(expand.grid(seq(1, 2), seq(1, 2))) > | index <- perm[which(perm[, 1] != perm[, 2]),] > | values[, index[, 1]] > | values[, index[, 2]] > | > | I found this thread on stackoverflow: > | > http://stackoverflow.com/questions/8435169/selecting-a-non-contiguous-submatrix-in-rcpp. > Are > | there any proceedings for non-contiguous submatrices in Rcpp? > > Not in Rcpp -- but Armadillo has it and this example on the Rcpp Gallery uses > it along with RcppArmadillo: > > http://gallery.rcpp.org/articles/armadillo-subsetting/ > > Dirk > > -- > Dirk Eddelbuettel | [email protected] | http://dirk.eddelbuettel.com _______________________________________________ Rcpp-devel mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
