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Diffstat (limited to 'src/eigen/Eigen/src/SparseCore/SparseView.h')
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diff --git a/src/eigen/Eigen/src/SparseCore/SparseView.h b/src/eigen/Eigen/src/SparseCore/SparseView.h new file mode 100644 index 000000000..7c4aea743 --- /dev/null +++ b/src/eigen/Eigen/src/SparseCore/SparseView.h @@ -0,0 +1,253 @@ +// This file is part of Eigen, a lightweight C++ template library +// for linear algebra. +// +// Copyright (C) 2011-2014 Gael Guennebaud <gael.guennebaud@inria.fr> +// Copyright (C) 2010 Daniel Lowengrub <lowdanie@gmail.com> +// +// 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_SPARSEVIEW_H +#define EIGEN_SPARSEVIEW_H + +namespace Eigen { + +namespace internal { + +template<typename MatrixType> +struct traits<SparseView<MatrixType> > : traits<MatrixType> +{ + typedef typename MatrixType::StorageIndex StorageIndex; + typedef Sparse StorageKind; + enum { + Flags = int(traits<MatrixType>::Flags) & (RowMajorBit) + }; +}; + +} // end namespace internal + +/** \ingroup SparseCore_Module + * \class SparseView + * + * \brief Expression of a dense or sparse matrix with zero or too small values removed + * + * \tparam MatrixType the type of the object of which we are removing the small entries + * + * This class represents an expression of a given dense or sparse matrix with + * entries smaller than \c reference * \c epsilon are removed. + * It is the return type of MatrixBase::sparseView() and SparseMatrixBase::pruned() + * and most of the time this is the only way it is used. + * + * \sa MatrixBase::sparseView(), SparseMatrixBase::pruned() + */ +template<typename MatrixType> +class SparseView : public SparseMatrixBase<SparseView<MatrixType> > +{ + typedef typename MatrixType::Nested MatrixTypeNested; + typedef typename internal::remove_all<MatrixTypeNested>::type _MatrixTypeNested; + typedef SparseMatrixBase<SparseView > Base; +public: + EIGEN_SPARSE_PUBLIC_INTERFACE(SparseView) + typedef typename internal::remove_all<MatrixType>::type NestedExpression; + + explicit SparseView(const MatrixType& mat, const Scalar& reference = Scalar(0), + const RealScalar &epsilon = NumTraits<Scalar>::dummy_precision()) + : m_matrix(mat), m_reference(reference), m_epsilon(epsilon) {} + + inline Index rows() const { return m_matrix.rows(); } + inline Index cols() const { return m_matrix.cols(); } + + inline Index innerSize() const { return m_matrix.innerSize(); } + inline Index outerSize() const { return m_matrix.outerSize(); } + + /** \returns the nested expression */ + const typename internal::remove_all<MatrixTypeNested>::type& + nestedExpression() const { return m_matrix; } + + Scalar reference() const { return m_reference; } + RealScalar epsilon() const { return m_epsilon; } + +protected: + MatrixTypeNested m_matrix; + Scalar m_reference; + RealScalar m_epsilon; +}; + +namespace internal { + +// TODO find a way to unify the two following variants +// This is tricky because implementing an inner iterator on top of an IndexBased evaluator is +// not easy because the evaluators do not expose the sizes of the underlying expression. + +template<typename ArgType> +struct unary_evaluator<SparseView<ArgType>, IteratorBased> + : public evaluator_base<SparseView<ArgType> > +{ + typedef typename evaluator<ArgType>::InnerIterator EvalIterator; + public: + typedef SparseView<ArgType> XprType; + + class InnerIterator : public EvalIterator + { + typedef typename XprType::Scalar Scalar; + public: + + EIGEN_STRONG_INLINE InnerIterator(const unary_evaluator& sve, Index outer) + : EvalIterator(sve.m_argImpl,outer), m_view(sve.m_view) + { + incrementToNonZero(); + } + + EIGEN_STRONG_INLINE InnerIterator& operator++() + { + EvalIterator::operator++(); + incrementToNonZero(); + return *this; + } + + using EvalIterator::value; + + protected: + const XprType &m_view; + + private: + void incrementToNonZero() + { + while((bool(*this)) && internal::isMuchSmallerThan(value(), m_view.reference(), m_view.epsilon())) + { + EvalIterator::operator++(); + } + } + }; + + enum { + CoeffReadCost = evaluator<ArgType>::CoeffReadCost, + Flags = XprType::Flags + }; + + explicit unary_evaluator(const XprType& xpr) : m_argImpl(xpr.nestedExpression()), m_view(xpr) {} + + protected: + evaluator<ArgType> m_argImpl; + const XprType &m_view; +}; + +template<typename ArgType> +struct unary_evaluator<SparseView<ArgType>, IndexBased> + : public evaluator_base<SparseView<ArgType> > +{ + public: + typedef SparseView<ArgType> XprType; + protected: + enum { IsRowMajor = (XprType::Flags&RowMajorBit)==RowMajorBit }; + typedef typename XprType::Scalar Scalar; + typedef typename XprType::StorageIndex StorageIndex; + public: + + class InnerIterator + { + public: + + EIGEN_STRONG_INLINE InnerIterator(const unary_evaluator& sve, Index outer) + : m_sve(sve), m_inner(0), m_outer(outer), m_end(sve.m_view.innerSize()) + { + incrementToNonZero(); + } + + EIGEN_STRONG_INLINE InnerIterator& operator++() + { + m_inner++; + incrementToNonZero(); + return *this; + } + + EIGEN_STRONG_INLINE Scalar value() const + { + return (IsRowMajor) ? m_sve.m_argImpl.coeff(m_outer, m_inner) + : m_sve.m_argImpl.coeff(m_inner, m_outer); + } + + EIGEN_STRONG_INLINE StorageIndex index() const { return m_inner; } + inline Index row() const { return IsRowMajor ? m_outer : index(); } + inline Index col() const { return IsRowMajor ? index() : m_outer; } + + EIGEN_STRONG_INLINE operator bool() const { return m_inner < m_end && m_inner>=0; } + + protected: + const unary_evaluator &m_sve; + Index m_inner; + const Index m_outer; + const Index m_end; + + private: + void incrementToNonZero() + { + while((bool(*this)) && internal::isMuchSmallerThan(value(), m_sve.m_view.reference(), m_sve.m_view.epsilon())) + { + m_inner++; + } + } + }; + + enum { + CoeffReadCost = evaluator<ArgType>::CoeffReadCost, + Flags = XprType::Flags + }; + + explicit unary_evaluator(const XprType& xpr) : m_argImpl(xpr.nestedExpression()), m_view(xpr) {} + + protected: + evaluator<ArgType> m_argImpl; + const XprType &m_view; +}; + +} // end namespace internal + +/** \ingroup SparseCore_Module + * + * \returns a sparse expression of the dense expression \c *this with values smaller than + * \a reference * \a epsilon removed. + * + * This method is typically used when prototyping to convert a quickly assembled dense Matrix \c D to a SparseMatrix \c S: + * \code + * MatrixXd D(n,m); + * SparseMatrix<double> S; + * S = D.sparseView(); // suppress numerical zeros (exact) + * S = D.sparseView(reference); + * S = D.sparseView(reference,epsilon); + * \endcode + * where \a reference is a meaningful non zero reference value, + * and \a epsilon is a tolerance factor defaulting to NumTraits<Scalar>::dummy_precision(). + * + * \sa SparseMatrixBase::pruned(), class SparseView */ +template<typename Derived> +const SparseView<Derived> MatrixBase<Derived>::sparseView(const Scalar& reference, + const typename NumTraits<Scalar>::Real& epsilon) const +{ + return SparseView<Derived>(derived(), reference, epsilon); +} + +/** \returns an expression of \c *this with values smaller than + * \a reference * \a epsilon removed. + * + * This method is typically used in conjunction with the product of two sparse matrices + * to automatically prune the smallest values as follows: + * \code + * C = (A*B).pruned(); // suppress numerical zeros (exact) + * C = (A*B).pruned(ref); + * C = (A*B).pruned(ref,epsilon); + * \endcode + * where \c ref is a meaningful non zero reference value. + * */ +template<typename Derived> +const SparseView<Derived> +SparseMatrixBase<Derived>::pruned(const Scalar& reference, + const RealScalar& epsilon) const +{ + return SparseView<Derived>(derived(), reference, epsilon); +} + +} // end namespace Eigen + +#endif |