Le 16/09/10 20:25, baptiste auguie a écrit :
Truth be told, I got lost in the recent discussions on the
best way to pass a real (complex) matrix from R to Armadillo and I've
been meaning to go back to this question.
Sorry for the confusion. I think Rcpp::as is fine. I need a bit more work in
RcppArmadillo for the interchangeability between ComplexVector and cx_mat.
Part of the confusion is also on whether one particular technique can
save making copies of the object.
Thanks again,
baptiste
If you want zero copies, you have to use the so-called "advanced
constructors" in http://arma.sourceforge.net/docs.html#Mat
Both data structures then share the memory, good things as well as bad
things can happen with this.
Rcpp::as I think makes two copies, which is one too many. I should
probably check this. as returns an object, and then the copy constructor
is used. Maybe not though. Perhaps someone else will know better how
compilers, etc ... work.
When I will get around to fix the mat constructor that takes a
NumericMatrix, only one copy should happen.
Romain
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