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108 lines
3.7 KiB
C++
108 lines
3.7 KiB
C++
// This file is part of Eigen, a lightweight C++ template library
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// for linear algebra. Eigen itself is part of the KDE project.
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//
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// Copyright (C) 2006-2008 Benoit Jacob <jacob@math.jussieu.fr>
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//
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// Eigen is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 3 of the License, or (at your option) any later version.
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//
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// Alternatively, you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as
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// published by the Free Software Foundation; either version 2 of
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// the License, or (at your option) any later version.
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//
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// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
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// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License and a copy of the GNU General Public License along with
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// Eigen. If not, see <http://www.gnu.org/licenses/>.
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#ifndef EIGEN_SCALARMULTIPLE_H
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#define EIGEN_SCALARMULTIPLE_H
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/** \class ScalarMultiple
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*
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* \brief Expression of the product of a matrix or vector by a scalar
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*
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* \param FactorTye the type of scalar by which to multiply
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* \param MatrixType the type of the matrix or vector to multiply
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*
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* This class represents an expression of the product of a matrix or vector by a scalar.
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* It is the return type of the operator* between a matrix or vector and a scalar, and most
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* of the time this is the only way it is used.
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*/
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template<typename MatrixType> class ScalarMultiple : NoOperatorEquals,
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public MatrixBase<typename MatrixType::Scalar, ScalarMultiple<MatrixType> >
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{
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public:
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typedef typename MatrixType::Scalar Scalar;
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typedef typename MatrixType::AsArg MatRef;
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friend class MatrixBase<Scalar, ScalarMultiple>;
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friend class MatrixBase<Scalar, ScalarMultiple>::Traits;
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typedef MatrixBase<Scalar, ScalarMultiple> Base;
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ScalarMultiple(const MatRef& matrix, Scalar factor)
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: m_matrix(matrix), m_factor(factor) {}
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private:
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enum {
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RowsAtCompileTime = MatrixType::Traits::RowsAtCompileTime,
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ColsAtCompileTime = MatrixType::Traits::ColsAtCompileTime,
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MaxRowsAtCompileTime = MatrixType::Traits::MaxRowsAtCompileTime,
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MaxColsAtCompileTime = MatrixType::Traits::MaxColsAtCompileTime
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};
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const ScalarMultiple& _asArg() const { return *this; }
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int _rows() const { return m_matrix.rows(); }
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int _cols() const { return m_matrix.cols(); }
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Scalar _coeff(int row, int col) const
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{
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return m_factor * m_matrix.coeff(row, col);
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}
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protected:
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const MatRef m_matrix;
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const Scalar m_factor;
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};
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/** relates MatrixBase sa class ScalarMultiple */
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template<typename Scalar, typename Derived>
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const ScalarMultiple<Derived>
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MatrixBase<Scalar, Derived>::operator*(const Scalar& scalar) const
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{
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return ScalarMultiple<Derived>(asArg(), scalar);
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}
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/** \relates MatrixBase \sa class ScalarMultiple */
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template<typename Scalar, typename Derived>
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const ScalarMultiple<Derived>
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MatrixBase<Scalar, Derived>::operator/(const Scalar& scalar) const
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{
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assert(NumTraits<Scalar>::HasFloatingPoint);
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return ScalarMultiple<Derived>(asArg(), static_cast<Scalar>(1) / scalar);
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}
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/** \sa ScalarMultiple */
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template<typename Scalar, typename Derived>
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Derived&
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MatrixBase<Scalar, Derived>::operator*=(const Scalar& other)
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{
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return *this = *this * other;
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}
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/** \sa ScalarMultiple */
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template<typename Scalar, typename Derived>
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Derived&
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MatrixBase<Scalar, Derived>::operator/=(const Scalar& other)
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{
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return *this = *this / other;
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}
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#endif // EIGEN_SCALARMULTIPLE_H
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