Re: [ublas-dev] Re: [boost] Re: Boost Mathematicians

From: Aleksey Gurtovoy (agurtovoy_at_[hidden])
Date: 2004-07-05 21:34:34

Jeremy Graham Siek writes:
> Hi Aleksey,

Hi Jeremy,

> 
> You are confusing the matrix abstraction with the multi-dimensional
> array abstraction.

I don't think so :).

> 
> A *linear algebra* algorithm will never need to be generalized
> in the fashion you advocate below. 

On the contrary, I think one can come up with numerous examples proving
the opposite. For instance:

    template< int i, int j, typename M >
    bool is_triangular( M const& m )
    {
        for ( typename index_type<M,i>::type k(0); k < m.size(int_<i>()); ++k )
            for ( typename index_type<M,j>::type l(0); l < value(k); ++l )
                if ( m[k][l] != 0 )
                    return false;

        return true;
    }

    template< typename M >
    bool is_upper_triangular( M const& m )
    {
        return is_triangular<0,1>( m );
    }

    template< typename M >
    bool is_lower_triangular( M const& m )
    {
        return is_triangular<1,0>( m );
    }

--
Aleksey Gurtovoy
MetaCommunications Engineering