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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_PRODUCT_H
#define EIGEN_PRODUCT_H
template<int Index, int Size, typename Lhs, typename Rhs>
struct ProductUnroller
{
static void run(int row, int col, const Lhs& lhs, const Rhs& rhs,
typename Lhs::Scalar &res)
{
ProductUnroller<Index-1, Size, Lhs, Rhs>::run(row, col, lhs, rhs, res);
res += lhs.coeff(row, Index) * rhs.coeff(Index, col);
}
};
template<int Size, typename Lhs, typename Rhs>
struct ProductUnroller<0, Size, Lhs, Rhs>
{
static void run(int row, int col, const Lhs& lhs, const Rhs& rhs,
typename Lhs::Scalar &res)
{
res = lhs.coeff(row, 0) * rhs.coeff(0, col);
}
};
template<int Index, typename Lhs, typename Rhs>
struct ProductUnroller<Index, Dynamic, Lhs, Rhs>
{
static void run(int, int, const Lhs&, const Rhs&, typename Lhs::Scalar&) {}
};
// prevent buggy user code from causing an infinite recursion
template<int Index, typename Lhs, typename Rhs>
struct ProductUnroller<Index, 0, Lhs, Rhs>
{
static void run(int, int, const Lhs&, const Rhs&, typename Lhs::Scalar&) {}
};
/** \class Product
*
* \brief Expression of the product of two matrices
*
* \param Lhs the type of the left-hand side
* \param Rhs the type of the right-hand side
*
* This class represents an expression of the product of two matrices.
* It is the return type of MatrixBase::lazyProduct(), which is used internally by
* the operator* between matrices, and most of the time this is the only way it is used.
*
* \sa class Sum, class Difference
*/
template<typename Lhs, typename Rhs>
struct ei_traits<Product<Lhs, Rhs> >
{
typedef typename Lhs::Scalar Scalar;
enum {
RowsAtCompileTime = Lhs::RowsAtCompileTime,
ColsAtCompileTime = Rhs::ColsAtCompileTime,
MaxRowsAtCompileTime = Lhs::MaxRowsAtCompileTime,
MaxColsAtCompileTime = Rhs::MaxColsAtCompileTime
};
};
template<typename Lhs, typename Rhs> class Product : NoOperatorEquals,
public MatrixBase<Product<Lhs, Rhs> >
{
public:
EIGEN_BASIC_PUBLIC_INTERFACE(Product)
typedef typename Lhs::AsArg LhsRef;
typedef typename Rhs::AsArg RhsRef;
Product(const LhsRef& lhs, const RhsRef& rhs)
: m_lhs(lhs), m_rhs(rhs)
{
assert(lhs.cols() == rhs.rows());
}
private:
const Product& _asArg() const { return *this; }
int _rows() const { return m_lhs.rows(); }
int _cols() const { return m_rhs.cols(); }
Scalar _coeff(int row, int col) const
{
Scalar res;
if(EIGEN_UNROLLED_LOOPS
&& Lhs::ColsAtCompileTime != Dynamic
&& Lhs::ColsAtCompileTime <= EIGEN_UNROLLING_LIMIT_PRODUCT)
ProductUnroller<Lhs::ColsAtCompileTime-1,
Lhs::ColsAtCompileTime <= EIGEN_UNROLLING_LIMIT_PRODUCT ? Lhs::ColsAtCompileTime : Dynamic,
LhsRef, RhsRef>
::run(row, col, m_lhs, m_rhs, res);
else
{
res = m_lhs.coeff(row, 0) * m_rhs.coeff(0, col);
for(int i = 1; i < m_lhs.cols(); i++)
res += m_lhs.coeff(row, i) * m_rhs.coeff(i, col);
}
return res;
}
protected:
const LhsRef m_lhs;
const RhsRef m_rhs;
};
/** \returns an expression of the matrix product of \c this and \a other, in this order.
*
* This function is used internally by the operator* between matrices. The difference between
* lazyProduct() and that operator* is that lazyProduct() only constructs and returns an
* expression without actually computing the matrix product, while the operator* between
* matrices immediately evaluates the product and returns the resulting matrix.
*
* \sa class Product
*/
template<typename Derived>
template<typename OtherDerived>
const Product<Derived, OtherDerived>
MatrixBase<Derived>::lazyProduct(const MatrixBase<OtherDerived> &other) const
{
return Product<Derived, OtherDerived>(asArg(), other.asArg());
}
/** \relates MatrixBase
*
* \returns the matrix product of \a mat1 and \a mat2. More precisely, the return statement is:
* \code return mat1.lazyProduct(mat2).eval(); \endcode
*
* \note This function causes an immediate evaluation. If you want to perform a matrix product
* without immediate evaluation, use MatrixBase::lazyProduct() instead.
*
* \sa MatrixBase::lazyProduct(), MatrixBase::operator*=(const MatrixBase&)
*/
template<typename Derived1, typename Derived2>
const Eval<Product<Derived1, Derived2> >
operator*(const MatrixBase<Derived1> &mat1, const MatrixBase<Derived2> &mat2)
{
return mat1.lazyProduct(mat2).eval();
}
/** replaces \c *this by \c *this * \a other.
*
* \returns a reference to \c *this
*/
template<typename Derived>
template<typename OtherDerived>
Derived &
MatrixBase<Derived>::operator*=(const MatrixBase<OtherDerived> &other)
{
return *this = *this * other;
}
#endif // EIGEN_PRODUCT_H
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