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

From: Julius Muschaweck (muschaweck_at_[hidden])
Date: 2003-02-01 03:51:48

Hi Joerg and everybody,

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.

I think this should work with const&'s since inner_prod is non mutating. 
I'd like to keep the const&'s.

Joerg: You suggested using compressed_matrix instead of sparse_matrix in 
your recent response to my matrix_row access problem. I couldn't find much 
in the documentation about the pros and cons of either type. Can you give 
me hint where to look for more information? Thanks.

Julius

Julius Muschaweck

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