[Rcpp-devel] Problems indexing matrics

[Dirk Eddelbuettel]

On 4 January 2012 at 15:59, Yasir Suhail wrote:
| Actually, 
| Rcpp::NumericMatrix output(x_s + x_k - 1, y_s + y_k - 1); output.fill(0.0);
| should do it.
| 
| Perhaps the following could be added to Matrix.h?
| 
| template <typename U> Matrix( const int& nrows_, const int& ncols, const U& u)
| :
|         VECTOR( Dimension( nrows_, ncols ) ),
|         nrows(nrows_)
|     { fill(u); }
| for completeness? Or does this conflict with the other constructor?

Well, zero fill is already a default.  

Look at the code for _Vector_ as matrix is 'merely' a vector with dimension
attributes; there are plenty of other constructors.

R> library(inline)
R> f <- cxxfunction(signature(), body='
+   return Rcpp::NumericMatrix(2,3);
+ ', plugin="Rcpp")
R> f()
     [,1] [,2] [,3]
[1,]    0    0    0
[2,]    0    0    0
R> 

Dirk

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