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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra. Eigen itself is part of the KDE project.
//
// Copyright (C) 2006-2008 Benoit Jacob <jacob@math.jussieu.fr>
//
// Eigen 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 3 of the License, or (at your option) any later version.
//
// Alternatively, 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 2 of
// the License, or (at your option) any later version.
//
// Eigen 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 or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.
#ifndef EIGEN_SCALARMULTIPLE_H
#define EIGEN_SCALARMULTIPLE_H
/** \class ScalarMultiple
*
* \brief Expression of the product of a matrix or vector by a scalar
*
* \param FactorTye the type of scalar by which to multiply
* \param MatrixType the type of the matrix or vector to multiply
*
* This class represents an expression of the product of a matrix or vector by a scalar.
* It is the return type of the operator* between a matrix or vector and a scalar, and most
* of the time this is the only way it is used.
*/
template<typename MatrixType> class ScalarMultiple : NoOperatorEquals,
public MatrixBase<typename MatrixType::Scalar, ScalarMultiple<MatrixType> >
{
public:
typedef typename MatrixType::Scalar Scalar;
typedef typename MatrixType::Ref MatRef;
friend class MatrixBase<Scalar, ScalarMultiple>;
friend class MatrixBase<Scalar, ScalarMultiple>::Traits;
typedef MatrixBase<Scalar, ScalarMultiple> Base;
ScalarMultiple(const MatRef& matrix, Scalar factor)
: m_matrix(matrix), m_factor(factor) {}
private:
enum {
RowsAtCompileTime = MatrixType::Traits::RowsAtCompileTime,
ColsAtCompileTime = MatrixType::Traits::ColsAtCompileTime,
MaxRowsAtCompileTime = MatrixType::Traits::MaxRowsAtCompileTime,
MaxColsAtCompileTime = MatrixType::Traits::MaxColsAtCompileTime
};
const ScalarMultiple& _ref() const { return *this; }
int _rows() const { return m_matrix.rows(); }
int _cols() const { return m_matrix.cols(); }
Scalar _coeff(int row, int col) const
{
return m_factor * m_matrix.coeff(row, col);
}
protected:
const MatRef m_matrix;
const Scalar m_factor;
};
/** relates MatrixBase sa class ScalarMultiple */
template<typename Scalar, typename Derived>
const ScalarMultiple<Derived>
MatrixBase<Scalar, Derived>::operator*(const Scalar& scalar) const
{
return ScalarMultiple<Derived>(ref(), scalar);
}
/** \relates MatrixBase \sa class ScalarMultiple */
template<typename Scalar, typename Derived>
const ScalarMultiple<Derived>
MatrixBase<Scalar, Derived>::operator/(const Scalar& scalar) const
{
assert(NumTraits<Scalar>::HasFloatingPoint);
return ScalarMultiple<Derived>(ref(), static_cast<Scalar>(1) / scalar);
}
/** \sa ScalarMultiple */
template<typename Scalar, typename Derived>
Derived&
MatrixBase<Scalar, Derived>::operator*=(const Scalar& other)
{
return *this = *this * other;
}
/** \sa ScalarMultiple */
template<typename Scalar, typename Derived>
Derived&
MatrixBase<Scalar, Derived>::operator/=(const Scalar& other)
{
return *this = *this / other;
}
#endif // EIGEN_SCALARMULTIPLE_H
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