Re: [boost] ublas: Cannot use inner_prod with const matrix&

From: Kresimir Fresl (fresl_at_[hidden])
Date: 2003-02-02 04:38:29

Julius Muschaweck wrote:

 >> now that sparse matrix_row's works with Joerg's latest CVS upload
 >> (thanks Joerg), a const& parameter that used to work with 1_29_0 doesn't
 >> anymore:
 >>
 >> using namespace boost::numeric;
 >> typedef ublas::matrix<double> TM;
 >>
 >> double InnerProdConst( const TM& A, const ublas::vector<double>& x )
 >>     {
 >>     return ublas::inner_prod( ublas::matrix_row< const TM >( A, 2 ), 
x );
 >>     }
 >>
 >> VC++.NET complains that some internal conversion loses qualifiers,
 >> This does compile with a non const matrix reference parameter, the same
 >> is true if I use a sparse_matrix or a compressed_matrix. I didn't try
 >> the other matrix types, but since this breaks with three matrix types,
 >> it looks like it has to do with matrix_row itself.

... or with VC++.NET  ;o)

Joerg Walter wrote:

> The following code compiles successfully with GCC 3.2.1:
> 
> #include <boost/numeric/ublas/matrix.hpp>
> 
> using namespace boost::numeric;
> typedef ublas::matrix<double> TM;
> 
> double InnerProdConst( const TM& A, const ublas::vector<double>& x )
>     {
>     return ublas::inner_prod( ublas::matrix_row< const TM >( A, 2 ), x );
>     }
> 
> int main()
>     {
>     ublas::matrix< double > A( 3, 3 );
>     ublas::vector< double > x( 3 );
>     std::cout << InnerProdConst( A, x ) << std::endl;
>     }

... and with Comeau's C++ compiler 4.3.0.1, too.

Also with the following addition to `main()':

   ublas::matrix< double > const CA( A );
   std::cout << InnerProdConst( CA, x ) << std::endl;

fres