Le 29/07/10 15:00, baptiste Auguié a écrit :
On Jul 29, 2010, at 1:23 PM, Romain Francois wrote:
Le 29/07/10 09:30, baptiste auguie a écrit :
Dear all,
I'm porting some R code to C++ using the armadillo framework (I'm
using operations on complex matrices, etc.). The final goal is of
course to wrap the code using RcppArmadillo. Currently, I'm still
struggling with my little C++ knowledge. Does anyone know of an
Armadillo mailing list where I could ask C++ questions?
From armadillo's faq http://arma.sourceforge.net/faq.html
you can find a link to a forum:
http://sourceforge.net/apps/phpbb/arma/
I don't know how I'd missed it, thanks!
No trouble. It was useful for me anyway as I did not know about creating
matrices from strings, so I learned something too. pretty nice.
It turns out that my example would work, one only needs to make sure that the
replacement has the correct type (matrix) and dimensions:
this works
mat A = "0 0 0; 0 0 0; 0 0 0;";
A.submat(1,1,1,1) = ones(1);
Thanks,
baptiste
Just in case, I'll ask here too. I have a small 3x3 matrix that I
generate in a nested for loop, and I want to insert this matrix as a
block inside a larger matrix. In R language, I'd want to use a
construct like,
A[ seq(ii, ii+2), seq(jj, jj+2)]<- matrix(rnorm(9), 3, 3)
I tried the following as a test,
mat A = "0 0 0; 0 0 0; 0 0 0;";
A.submat(1,1,1,1) = 1;
but it seems that .submat is only to view elements, not assign them
(the `[<-` method in R). Any tip?
Sincerely,
baptiste
That is the kind of thing we should add in Rcpp sugar at some point, but
currently I don't know how to.
Romain
--
Romain Francois
Professional R Enthusiast
+33(0) 6 28 91 30 30
http://romainfrancois.blog.free.fr
|- http://bit.ly/aryfrk : useR! 2010
|- http://bit.ly/bc8jNi : Rcpp 0.8.4
`- http://bit.ly/dz0RlX : bibtex 0.2-1
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