MatrixAdapter.hpp

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/* 
 * MatrixAdapter.hpp 
 *
 * Copyright (C) 2003 Thomas Seidel <thomas.seidel@univie.ac.at>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; see the file COPYING. If not, write to
 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */
 
#ifndef CDPL_MATH_MATRIXADAPTER_HPP
#define CDPL_MATH_MATRIXADAPTER_HPP
 
#include <type_traits>
 
#include "CDPL/Math/Expression.hpp"
#include "CDPL/Math/TypeTraits.hpp"
 
 
namespace CDPL
{
 
    namespace Math
    {
 
        template <typename T>
        class Range;
 
        struct Lower
        {
 
            template <typename M>
            static typename M::ConstReference get(const M& m, typename M::SizeType i, typename M::SizeType j)
            {
                if (i >= j)
                    return m.getData()(i, j);
 
                return m.zero;
            }
        };
 
        struct UnitLower
        {
 
            template <typename M>
            static typename M::ConstReference get(const M& m, typename M::SizeType i, typename M::SizeType j)
            {
                if (i == j)
                    return m.one;
 
                if (i >= j)
                    return m.getData()(i, j);
 
                return m.zero;
            }
        };
 
        struct Upper
        {
 
            template <typename M>
            static typename M::ConstReference get(const M& m, typename M::SizeType i, typename M::SizeType j)
            {
                if (i <= j)
                    return m.getData()(i, j);
 
                return m.zero;
            }
        };
 
        struct UnitUpper
        {
 
            template <typename M>
            static typename M::ConstReference get(const M& m, typename M::SizeType i, typename M::SizeType j)
            {
                if (i == j)
                    return m.one;
 
                if (i <= j)
                    return m.getData()(i, j);
 
                return m.zero;
            }
        };
 
        template <typename M, typename Tri>
        class TriangularAdapter : public MatrixExpression<TriangularAdapter<M, Tri> >
        {
 
            typedef TriangularAdapter<M, Tri> SelfType;
 
            friend struct Lower;
            friend struct UnitLower;
            friend struct Upper;
            friend struct UnitUpper;
 
          public:
            typedef M                                                        MatrixType;
            typedef Tri                                                      TriangularType;
            typedef typename M::SizeType                                     SizeType;
            typedef typename M::DifferenceType                               DifferenceType;
            typedef typename M::ValueType                                    ValueType;
            typedef typename M::ConstReference                               ConstReference;
            typedef typename std::conditional<std::is_const<M>::value,
                                              typename M::ConstReference,
                                              typename M::Reference>::type   Reference;
            typedef typename std::conditional<std::is_const<M>::value,
                                              typename M::ConstClosureType,
                                              typename M::ClosureType>::type MatrixClosureType;
            typedef const SelfType                                           ConstClosureType;
            typedef SelfType                                                 ClosureType;
            typedef Range<SizeType>                                          RangeType;
 
            explicit TriangularAdapter(MatrixType& m):
                data(m) {}
 
            ConstReference operator()(SizeType i, SizeType j) const
            {
                return TriangularType::template get<SelfType>(*this, i, j);
            }
 
            SizeType getSize1() const
            {
                return data.getSize1();
            }
 
            SizeType getSize2() const
            {
                return data.getSize2();
            }
 
            MatrixClosureType& getData()
            {
                return data;
            }
 
            const MatrixClosureType& getData() const
            {
                return data;
            }
 
            bool isEmpty() const
            {
                return (data.getSize1() == 0 || data.getSize2() == 0);
            }
 
          private:
            MatrixClosureType      data;
            static const ValueType zero;
            static const ValueType one;
        };
 
        template <typename M, typename Tri>
        const typename TriangularAdapter<M, Tri>::ValueType TriangularAdapter<M, Tri>::zero = TriangularAdapter<M, Tri>::ValueType();
 
        template <typename M, typename Tri>
        const typename TriangularAdapter<M, Tri>::ValueType TriangularAdapter<M, Tri>::one = TriangularAdapter<M, Tri>::ValueType(1);
 
        template <typename M, typename Tri>
        struct VectorTemporaryTraits<TriangularAdapter<M, Tri> > : public VectorTemporaryTraits<M>
        {};
 
        template <typename M, typename Tri>
        struct VectorTemporaryTraits<const TriangularAdapter<M, Tri> > : public VectorTemporaryTraits<M>
        {};
 
        template <typename M, typename Tri>
        struct MatrixTemporaryTraits<TriangularAdapter<M, Tri> > : public MatrixTemporaryTraits<M>
        {};
 
        template <typename M, typename Tri>
        struct MatrixTemporaryTraits<const TriangularAdapter<M, Tri> > : public MatrixTemporaryTraits<M>
        {};
 
        template <typename Tri, typename E>
        TriangularAdapter<E, Tri>
        triang(MatrixExpression<E>& e)
        {
            return TriangularAdapter<E, Tri>(e());
        }
 
        template <typename Tri, typename E>
        TriangularAdapter<const E, Tri>
        triang(const MatrixExpression<E>& e)
        {
            return TriangularAdapter<const E, Tri>(e());
        }
    } // namespace Math
} // namespace CDPL
 
#endif // CDPL_MATH_MATRIXADAPTER_HPP