[ublas] vector * vector ambiguity causes compilation error

Subject: [ublas] vector * vector ambiguity causes compilation error
From: Mark Johnson (mj1_at_[hidden])
Date: 2009-08-05 10:52:04

I'm trying to use the * operator on a pair of vectors, but it seems the 
vector * scalar and scalar * vector version of the operators also 
match.  Can anyone recommend a fix or a work-around? I'm using the 
version of Boost that comes pre-installed on Fedora 11, which I think is 
1.37.

Thanks in advance for your help,

Mark

Example:

    #include <iostream>
    #include <boost/numeric/ublas/io.hpp>
    #include <boost/numeric/ublas/vector.hpp>
    #include <boost/numeric/ublas/vector_expression.hpp>

    int main(int argc, char** argv) {
       boost::numeric::ublas::scalar_vector<double> v(2, 2);
       std::cout << "v = " << v*v << std::endl;
    }

when compiled produces

    g++ utmp.cc
    utmp.cc: In function 'int main(int, char**)':
    utmp.cc:8: error: ambiguous overload for 'operator*' in 'v * v'
    /usr/include/boost/numeric/ublas/vector_expression.hpp:1399: note:
    candidates are: typename
    boost::numeric::ublas::vector_binary_scalar2_traits<E1, const T2,
    boost::numeric::ublas::scalar_multiplies<typename E1::value_type,
    T2> >::result_type boost::numeric::ublas::operator*(const
    boost::numeric::ublas::vector_expression<E>&, const T2&) [with E1 =
    boost::numeric::ublas::vector<double,
    boost::numeric::ublas::unbounded_array<double,
    std::allocator<double> > >, T2 =
    boost::numeric::ublas::vector<double,
    boost::numeric::ublas::unbounded_array<double,
    std::allocator<double> > >]
    /usr/include/boost/numeric/ublas/vector_expression.hpp:1174:
    note:                 typename
    boost::numeric::ublas::vector_binary_scalar1_traits<const T1, E2,
    boost::numeric::ublas::scalar_multiplies<T1, typename
    E2::value_type> >::result_type
    boost::numeric::ublas::operator*(const T1&, const
    boost::numeric::ublas::vector_expression<E2>&) [with T1 =
    boost::numeric::ublas::vector<double,
    boost::numeric::ublas::unbounded_array<double,
    std::allocator<double> > >, E2 =
    boost::numeric::ublas::vector<double,
    boost::numeric::ublas::unbounded_array<double,
    std::allocator<double> > >]