[Rcpp-devel] fill a NumericMatrix row by row

[Michael Love]

Not a question here, but a note.  Earlier there was an email about filling
a NumericMatrix row by row.

http://lists.r-forge.r-project.org/pipermail/rcpp-devel/2013-March/005390.html

I noticed that for Rcpp 0.10.2 it was possible to fill a NumericMatrix with
NumericVectors, but since Rcpp 0.10.3 it does so while printing out some
lines.

As recommended, I have switched to using Armadillo matrices, which doesn't
print out these lines.

-Mike

example with NumericMatrix, fill a matrix mat0 by row with the vector vec0:

library(Rcpp)
library(inline)
code <- '
   Rcpp::NumericMatrix mat(mat0);
   Rcpp::NumericVector vec(vec0);
   for (int i = 0; i < mat.nrow(); i++) {
      mat(i,_) = vec;
   }
   return Rcpp::wrap(mat);
'
f <-
cxxfunction(signature(mat0="numeric",vec0="numeric"),code,plugin="Rcpp")
mat0 <- matrix(c(1:4),nrow=2)
vec0 <- c(5,6)
f(mat0,vec0)

produces:

MatrixRow::get_parent_index(int = 0), parent_nrow = 2 >> 0
MatrixRow::get_parent_index(int = 1), parent_nrow = 2 >> 2
MatrixRow::get_parent_index(int = 0), parent_nrow = 2 >> 0
MatrixRow::get_parent_index(int = 1), parent_nrow = 2 >> 2
     [,1] [,2]
[1,]    5    6
[2,]    5    6


Example with Armadillo:

arma.code <- '
   arma::mat mat = Rcpp::as<arma::mat>(mat0);
   arma::rowvec vec = Rcpp::as<arma::rowvec>(vec0);
   for (int i = 0; i < mat.n_rows; i++) {
      mat.row(i) = vec;
   }
   return Rcpp::wrap(mat);
'
arma.f <-
cxxfunction(signature(mat0="numeric",vec0="numeric"),arma.code,plugin="RcppArmadillo")
arma.f(mat0,vec0)

produces:

     [,1] [,2]
[1,]    5    6
[2,]    5    6


> sessionInfo()
R Under development (unstable) (2013-03-20 r62335)
Platform: x86_64-unknown-linux-gnu (64-bit)

locale:
[1] C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] RcppArmadillo_0.3.800.1 inline_0.3.11           Rcpp_0.10.3
[4] Defaults_1.1-1          BiocInstaller_1.9.8

loaded via a namespace (and not attached):
[1] tools_3.1.0
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