Difference.h

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/*
 *  Copyright (C) 2012 Josh Bialkowski (jbialk@mit.edu)
 *
 *  This file is part of mpblocks.
 *
 *  mpblocks is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  mpblocks is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with mpblocks.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef MPBLOCKS_POLYNOMIAL_DIFFERENCE_H_
#define MPBLOCKS_POLYNOMIAL_DIFFERENCE_H_

namespace   mpblocks {
namespace polynomial {

template <typename Scalar, class Exp1, class Exp2>
class Difference :
    public RValue<
            Scalar,
            Difference<Scalar,Exp1,Exp2> >
{
    Exp1 const& m_A;
    Exp2 const& m_B;

    public:
        typedef unsigned int Size_t;

        Difference( Exp1 const& A, Exp2 const& B ):
            m_A(A),
            m_B(B)
        {
        }

        Size_t size() const
        {
            return std::max( (Size_t)m_A.size(), (Size_t)m_B.size() );
        }

        Scalar operator[]( Size_t i ) const
        {
            if( i < m_A.size() && i < m_B.size() )
                return (m_A[i] - m_B[i]);
            else if( i < m_A.size() )
                return m_A[i];
            else if( i < m_B.size() )
                return -m_B[i];
            else
                return 0;
        }

        Scalar eval( Scalar x )
        {
            return m_A.eval(x) + m_B.eval(x);
        }
};




template <typename Scalar, class Exp1, class Exp2>
Difference<Scalar,Exp1,Exp2> operator-(
        RValue<Scalar,Exp1> const& A,
        RValue<Scalar,Exp2> const& B )
{
    typedef Difference<Scalar,Exp1,Exp2> Difference_t;
    return Difference_t(
            static_cast<Exp1 const&>(A),
            static_cast<Exp2 const&>(B));
}




} // polynomial
} // mpblocks





#endif // DIFFERENCE_H_