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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2009-2015 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
#ifndef EIGEN_SPARSE_DIAGONAL_PRODUCT_H
#define EIGEN_SPARSE_DIAGONAL_PRODUCT_H
#include "./InternalHeaderCheck.h"
namespace Eigen {
// The product of a diagonal matrix with a sparse matrix can be easily
// implemented using expression template.
// We have two consider very different cases:
// 1 - diag * row-major sparse
// => each inner vector <=> scalar * sparse vector product
// => so we can reuse CwiseUnaryOp::InnerIterator
// 2 - diag * col-major sparse
// => each inner vector <=> densevector * sparse vector cwise product
// => again, we can reuse specialization of CwiseBinaryOp::InnerIterator
// for that particular case
// The two other cases are symmetric.
namespace internal {
enum {
SDP_AsScalarProduct,
SDP_AsCwiseProduct
};
template<typename SparseXprType, typename DiagonalCoeffType, int SDP_Tag>
struct sparse_diagonal_product_evaluator;
template<typename Lhs, typename Rhs, int ProductTag>
struct product_evaluator<Product<Lhs, Rhs, DefaultProduct>, ProductTag, DiagonalShape, SparseShape>
: public sparse_diagonal_product_evaluator<Rhs, typename Lhs::DiagonalVectorType, Rhs::Flags&RowMajorBit?SDP_AsScalarProduct:SDP_AsCwiseProduct>
{
typedef Product<Lhs, Rhs, DefaultProduct> XprType;
enum { CoeffReadCost = HugeCost, Flags = Rhs::Flags&RowMajorBit, Alignment = 0 }; // FIXME CoeffReadCost & Flags
typedef sparse_diagonal_product_evaluator<Rhs, typename Lhs::DiagonalVectorType, Rhs::Flags&RowMajorBit?SDP_AsScalarProduct:SDP_AsCwiseProduct> Base;
explicit product_evaluator(const XprType& xpr) : Base(xpr.rhs(), xpr.lhs().diagonal()) {}
};
template<typename Lhs, typename Rhs, int ProductTag>
struct product_evaluator<Product<Lhs, Rhs, DefaultProduct>, ProductTag, SparseShape, DiagonalShape>
: public sparse_diagonal_product_evaluator<Lhs, Transpose<const typename Rhs::DiagonalVectorType>, Lhs::Flags&RowMajorBit?SDP_AsCwiseProduct:SDP_AsScalarProduct>
{
typedef Product<Lhs, Rhs, DefaultProduct> XprType;
enum { CoeffReadCost = HugeCost, Flags = Lhs::Flags&RowMajorBit, Alignment = 0 }; // FIXME CoeffReadCost & Flags
typedef sparse_diagonal_product_evaluator<Lhs, Transpose<const typename Rhs::DiagonalVectorType>, Lhs::Flags&RowMajorBit?SDP_AsCwiseProduct:SDP_AsScalarProduct> Base;
explicit product_evaluator(const XprType& xpr) : Base(xpr.lhs(), xpr.rhs().diagonal().transpose()) {}
};
template<typename SparseXprType, typename DiagonalCoeffType>
struct sparse_diagonal_product_evaluator<SparseXprType, DiagonalCoeffType, SDP_AsScalarProduct>
{
protected:
typedef typename evaluator<SparseXprType>::InnerIterator SparseXprInnerIterator;
typedef typename SparseXprType::Scalar Scalar;
public:
class InnerIterator : public SparseXprInnerIterator
{
public:
InnerIterator(const sparse_diagonal_product_evaluator &xprEval, Index outer)
: SparseXprInnerIterator(xprEval.m_sparseXprImpl, outer),
m_coeff(xprEval.m_diagCoeffImpl.coeff(outer))
{}
EIGEN_STRONG_INLINE Scalar value() const { return m_coeff * SparseXprInnerIterator::value(); }
protected:
typename DiagonalCoeffType::Scalar m_coeff;
};
sparse_diagonal_product_evaluator(const SparseXprType &sparseXpr, const DiagonalCoeffType &diagCoeff)
: m_sparseXprImpl(sparseXpr), m_diagCoeffImpl(diagCoeff)
{}
Index nonZerosEstimate() const { return m_sparseXprImpl.nonZerosEstimate(); }
protected:
evaluator<SparseXprType> m_sparseXprImpl;
evaluator<DiagonalCoeffType> m_diagCoeffImpl;
};
template<typename SparseXprType, typename DiagCoeffType>
struct sparse_diagonal_product_evaluator<SparseXprType, DiagCoeffType, SDP_AsCwiseProduct>
{
typedef typename SparseXprType::Scalar Scalar;
typedef typename SparseXprType::StorageIndex StorageIndex;
typedef typename nested_eval<DiagCoeffType,SparseXprType::IsRowMajor ? SparseXprType::RowsAtCompileTime
: SparseXprType::ColsAtCompileTime>::type DiagCoeffNested;
class InnerIterator
{
typedef typename evaluator<SparseXprType>::InnerIterator SparseXprIter;
public:
InnerIterator(const sparse_diagonal_product_evaluator &xprEval, Index outer)
: m_sparseIter(xprEval.m_sparseXprEval, outer), m_diagCoeffNested(xprEval.m_diagCoeffNested)
{}
inline Scalar value() const { return m_sparseIter.value() * m_diagCoeffNested.coeff(index()); }
inline StorageIndex index() const { return m_sparseIter.index(); }
inline Index outer() const { return m_sparseIter.outer(); }
inline Index col() const { return SparseXprType::IsRowMajor ? m_sparseIter.index() : m_sparseIter.outer(); }
inline Index row() const { return SparseXprType::IsRowMajor ? m_sparseIter.outer() : m_sparseIter.index(); }
EIGEN_STRONG_INLINE InnerIterator& operator++() { ++m_sparseIter; return *this; }
inline operator bool() const { return m_sparseIter; }
protected:
SparseXprIter m_sparseIter;
DiagCoeffNested m_diagCoeffNested;
};
sparse_diagonal_product_evaluator(const SparseXprType &sparseXpr, const DiagCoeffType &diagCoeff)
: m_sparseXprEval(sparseXpr), m_diagCoeffNested(diagCoeff)
{}
Index nonZerosEstimate() const { return m_sparseXprEval.nonZerosEstimate(); }
protected:
evaluator<SparseXprType> m_sparseXprEval;
DiagCoeffNested m_diagCoeffNested;
};
} // end namespace internal
} // end namespace Eigen
#endif // EIGEN_SPARSE_DIAGONAL_PRODUCT_H