[Rcpp-devel] armadillo mailing list?

[baptiste Auguié]

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!

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
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