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

From: Joerg Walter (jhr.walter_at_[hidden])
Date: 2003-02-02 06:51:43

Hi Kresimir,

you 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)

... or with ublas' perception of MS compilers ;-). I've just upgraded boost
on my old Win98 box from 1_25_1 to 1_29_0 and checked Julius' sample with
MSVC 6.0. He is right that it doesn't compile with the latest ublas
snapshot, but the fix is surprisingly simple. I only had to disable the
definition of

// #define BOOST_UBLAS_NO_SMART_PROXIES

in the MSVC section of config.hpp. This now seems to work due to our
migration to MPL (thanks, Aleksey!). The last compiler which doesn't support
these constructs is Borland.

> 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.

And with MSVC 6.0 now, too.

> Also with the following addition to `main()':
>
>    ublas::matrix< double > const CA( A );
>    std::cout << InnerProdConst( CA, x ) << std::endl;

Hopefully, too. Didn't check this yet.

Thanks,

Joerg