[Boost-users] uBlas matrix * matrix operation

From: Dave Steffen (dgsteffen_at_[hidden])
Date: 2006-07-26 10:53:51

Hi Folks,

This is my first excursion into uBlas.  I'm getting an "ambiguous
overload for 'operator*' in 'a * b' " sort of error out of this:

#include <boost/numeric/ublas/vector.hpp>
#include <boost/numeric/ublas/matrix.hpp>
#include <boost/numeric/ublas/matrix_expression.hpp>
namespace UB
{
    using namespace boost::numeric::ublas;

    template <int N>  struct Type
    {
        typedef matrix<double, row_major, bounded_array<double, N*N> > matrix;
    };
}

// elsewhere...

   typename UB::Type<N>::matrix a(N,N), b(N,N);

    for (int i = 0; i < N; ++i)
        for (int j = 0; j < N; ++j)
            {
                a(i,j) = 1.0 / (i + j+1);
                b(i,j) = 1.0 / (i + j+1);
            }
    

    a * b;

The error (from GCC 3.4.6) is this ugly thing:

/usr/local/home/dgsteffen/local/GCC34/Boost/1_32/boost/numeric/ublas/matrix_expression.hpp:3632: note: candidates are: typename boost::numeric::ublas::matrix_binary_scalar2_traits<E1, const T2, boost::numeric::ublas::scalar_multiplies<typename E1::value_type, T2>, boost::numeric::ublas::scalar_reference<const T2> >::result_type boost::numeric::ublas::operator*(const boost::numeric::ublas::matrix_expression<E>&, const T2&) [with E1 = boost::numeric::ublas::matrix<double, boost::numeric::ublas::row_major, boost::numeric::ublas::bounded_array<double, 441u, std::allocator<double> > >, T2 = boost::numeric::ublas::matrix<double, boost::numeric::ublas::row_major, boost::numeric::ublas::bounded_array<double, 441u, std::allocator<double> > >]
/usr/local/home/dgsteffen/local/GCC34/Boost/1_32/boost/numeric/ublas/matrix_expression.hpp:3162: note:                 typename boost::numeric::ublas::matrix_binary_scalar1_traits<const T1, E2, boost::numeric::ublas::scalar_multiplies<T1, typename E2::value_type>, boost::numeric::ublas::scalar_reference<const T1> >::result_type boost::numeric::ublas::operator*(const T1&, const boost::numeric::ublas::matrix_expression<E2>&) [with T1 = boost::numeric::ublas::matrix<double, boost::numeric::ublas::row_major, boost::numeric::ublas::bounded_array<double, 441u, std::allocator<double> > >, E2 = boost::numeric::ublas::matrix<double, boost::numeric::ublas::row_major, boost::numeric::ublas::bounded_array<double, 441u, std::allocator<double> > >]

Any thoughts on what I'm doing wrong?

Thanks!

----------------------------------------------------------------------
Dave Steffen, Ph.D.      
Software Engineer IV              Disobey this command!
Numerica Corporation
ph [phone] x27    
fax [phone]                   - Douglas Hofstadter
dgsteffen_at_[hidden]
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