Eigen/src/Core/Product.h

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2011 Gael Guennebaud <gael.guennebaud@inria.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

namespace Eigen {

template<typename Lhs, typename Rhs> class Product;
template<typename Lhs, typename Rhs, typename StorageKind> class ProductImpl;

/** \class Product
  * \ingroup Core_Module
  *
  * \brief Expression of the product of two arbitrary matrices or vectors
  *
  * \param Lhs the type of the left-hand side expression
  * \param Rhs the type of the right-hand side expression
  *
  * This class represents an expression of the product of two arbitrary matrices.
  *
  */

// Use ProductReturnType to get correct traits, in particular vectorization flags
namespace internal {
template<typename Lhs, typename Rhs>
struct traits<Product<Lhs, Rhs> >
  : traits<typename ProductReturnType<Lhs, Rhs>::Type>
{ 
  // We want A+B*C to be of type Product<Matrix, Sum> and not Product<Matrix, Matrix>
  // TODO: This flag should eventually go in a separate evaluator traits class
  enum {
    Flags = traits<typename ProductReturnType<Lhs, Rhs>::Type>::Flags & ~EvalBeforeNestingBit
  };
};
} // end namespace internal


template<typename Lhs, typename Rhs>
class Product : public ProductImpl<Lhs,Rhs,typename internal::promote_storage_type<typename internal::traits<Lhs>::StorageKind,
                                                                            typename internal::traits<Rhs>::StorageKind>::ret>
{
  public:
    
    typedef typename ProductImpl<
        Lhs, Rhs,
        typename internal::promote_storage_type<typename Lhs::StorageKind,
                                                typename Rhs::StorageKind>::ret>::Base Base;
    EIGEN_GENERIC_PUBLIC_INTERFACE(Product)

    typedef typename Lhs::Nested LhsNested;
    typedef typename Rhs::Nested RhsNested;
    typedef typename internal::remove_all<LhsNested>::type LhsNestedCleaned;
    typedef typename internal::remove_all<RhsNested>::type RhsNestedCleaned;

    Product(const Lhs& lhs, const Rhs& rhs) : m_lhs(lhs), m_rhs(rhs)
    {
      eigen_assert(lhs.cols() == rhs.rows()
        && "invalid matrix product"
        && "if you wanted a coeff-wise or a dot product use the respective explicit functions");
    }

    inline Index rows() const { return m_lhs.rows(); }
    inline Index cols() const { return m_rhs.cols(); }

    const LhsNestedCleaned& lhs() const { return m_lhs; }
    const RhsNestedCleaned& rhs() const { return m_rhs; }

  protected:

    const LhsNested m_lhs;
    const RhsNested m_rhs;
};

template<typename Lhs, typename Rhs>
class ProductImpl<Lhs,Rhs,Dense> : public internal::dense_xpr_base<Product<Lhs,Rhs> >::type
{
    typedef Product<Lhs, Rhs> Derived;
  public:

    typedef typename internal::dense_xpr_base<Product<Lhs, Rhs> >::type Base;
    EIGEN_DENSE_PUBLIC_INTERFACE(Derived)
};

/***************************************************************************
* Implementation of matrix base methods
***************************************************************************/


/** \internal used to test the evaluator only
  */
template<typename Lhs,typename Rhs>
const Product<Lhs,Rhs>
prod(const Lhs& lhs, const Rhs& rhs)
{
  return Product<Lhs,Rhs>(lhs,rhs);
}

} // end namespace Eigen

#endif // EIGEN_PRODUCT_H