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// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2017 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_INDEXED_VIEW_H
#define EIGEN_INDEXED_VIEW_H
namespace Eigen {
namespace internal {
template<typename XprType, typename RowIndices, typename ColIndices>
struct traits<IndexedView<XprType, RowIndices, ColIndices> >
: traits<XprType>
{
enum {
RowsAtCompileTime = int(array_size<RowIndices>::value),
ColsAtCompileTime = int(array_size<ColIndices>::value),
MaxRowsAtCompileTime = RowsAtCompileTime != Dynamic ? int(RowsAtCompileTime) : Dynamic,
MaxColsAtCompileTime = ColsAtCompileTime != Dynamic ? int(ColsAtCompileTime) : Dynamic,
XprTypeIsRowMajor = (int(traits<XprType>::Flags)&RowMajorBit) != 0,
IsRowMajor = (MaxRowsAtCompileTime==1&&MaxColsAtCompileTime!=1) ? 1
: (MaxColsAtCompileTime==1&&MaxRowsAtCompileTime!=1) ? 0
: XprTypeIsRowMajor,
RowIncr = int(get_compile_time_incr<RowIndices>::value),
ColIncr = int(get_compile_time_incr<ColIndices>::value),
InnerIncr = IsRowMajor ? ColIncr : RowIncr,
OuterIncr = IsRowMajor ? RowIncr : ColIncr,
HasSameStorageOrderAsXprType = (IsRowMajor == XprTypeIsRowMajor),
XprInnerStride = HasSameStorageOrderAsXprType ? int(inner_stride_at_compile_time<XprType>::ret) : int(outer_stride_at_compile_time<XprType>::ret),
XprOuterstride = HasSameStorageOrderAsXprType ? int(outer_stride_at_compile_time<XprType>::ret) : int(inner_stride_at_compile_time<XprType>::ret),
InnerSize = XprTypeIsRowMajor ? ColsAtCompileTime : RowsAtCompileTime,
IsBlockAlike = InnerIncr==1 && OuterIncr==1,
IsInnerPannel = HasSameStorageOrderAsXprType && is_same<AllRange<InnerSize>,typename conditional<XprTypeIsRowMajor,ColIndices,RowIndices>::type>::value,
InnerStrideAtCompileTime = InnerIncr<0 || InnerIncr==DynamicIndex || XprInnerStride==Dynamic ? Dynamic : XprInnerStride * InnerIncr,
OuterStrideAtCompileTime = OuterIncr<0 || OuterIncr==DynamicIndex || XprOuterstride==Dynamic ? Dynamic : XprOuterstride * OuterIncr,
ReturnAsScalar = is_same<RowIndices,SingleRange>::value && is_same<ColIndices,SingleRange>::value,
ReturnAsBlock = (!ReturnAsScalar) && IsBlockAlike,
ReturnAsIndexedView = (!ReturnAsScalar) && (!ReturnAsBlock),
// FIXME we deal with compile-time strides if and only if we have DirectAccessBit flag,
// but this is too strict regarding negative strides...
DirectAccessMask = (int(InnerIncr)!=UndefinedIncr && int(OuterIncr)!=UndefinedIncr && InnerIncr>=0 && OuterIncr>=0) ? DirectAccessBit : 0,
FlagsRowMajorBit = IsRowMajor ? RowMajorBit : 0,
FlagsLvalueBit = is_lvalue<XprType>::value ? LvalueBit : 0,
FlagsLinearAccessBit = (RowsAtCompileTime == 1 || ColsAtCompileTime == 1) ? LinearAccessBit : 0,
Flags = (traits<XprType>::Flags & (HereditaryBits | DirectAccessMask )) | FlagsLvalueBit | FlagsRowMajorBit | FlagsLinearAccessBit
};
typedef Block<XprType,RowsAtCompileTime,ColsAtCompileTime,IsInnerPannel> BlockType;
};
}
template<typename XprType, typename RowIndices, typename ColIndices, typename StorageKind>
class IndexedViewImpl;
/** \class IndexedView
* \ingroup Core_Module
*
* \brief Expression of a non-sequential sub-matrix defined by arbitrary sequences of row and column indices
*
* \tparam XprType the type of the expression in which we are taking the intersections of sub-rows and sub-columns
* \tparam RowIndices the type of the object defining the sequence of row indices
* \tparam ColIndices the type of the object defining the sequence of column indices
*
* This class represents an expression of a sub-matrix (or sub-vector) defined as the intersection
* of sub-sets of rows and columns, that are themself defined by generic sequences of row indices \f$ \{r_0,r_1,..r_{m-1}\} \f$
* and column indices \f$ \{c_0,c_1,..c_{n-1} \}\f$. Let \f$ A \f$ be the nested matrix, then the resulting matrix \f$ B \f$ has \c m
* rows and \c n columns, and its entries are given by: \f$ B(i,j) = A(r_i,c_j) \f$.
*
* The \c RowIndices and \c ColIndices types must be compatible with the following API:
* \code
* <integral type> operator[](Index) const;
* Index size() const;
* \endcode
*
* Typical supported types thus include:
* - std::vector<int>
* - std::valarray<int>
* - std::array<int>
* - Plain C arrays: int[N]
* - Eigen::ArrayXi
* - decltype(ArrayXi::LinSpaced(...))
* - Any view/expressions of the previous types
* - Eigen::ArithmeticSequence
* - Eigen::internal::AllRange (helper for Eigen::all)
* - Eigen::internal::SingleRange (helper for single index)
* - etc.
*
* In typical usages of %Eigen, this class should never be used directly. It is the return type of
* DenseBase::operator()(const RowIndices&, const ColIndices&).
*
* \sa class Block
*/
template<typename XprType, typename RowIndices, typename ColIndices>
class IndexedView : public IndexedViewImpl<XprType, RowIndices, ColIndices, typename internal::traits<XprType>::StorageKind>
{
public:
typedef typename IndexedViewImpl<XprType, RowIndices, ColIndices, typename internal::traits<XprType>::StorageKind>::Base Base;
EIGEN_GENERIC_PUBLIC_INTERFACE(IndexedView)
EIGEN_INHERIT_ASSIGNMENT_OPERATORS(IndexedView)
typedef typename internal::ref_selector<XprType>::non_const_type MatrixTypeNested;
typedef typename internal::remove_all<XprType>::type NestedExpression;
template<typename T0, typename T1>
IndexedView(XprType& xpr, const T0& rowIndices, const T1& colIndices)
: m_xpr(xpr), m_rowIndices(rowIndices), m_colIndices(colIndices)
{}
/** \returns number of rows */
Index rows() const { return internal::size(m_rowIndices); }
/** \returns number of columns */
Index cols() const { return internal::size(m_colIndices); }
/** \returns the nested expression */
const typename internal::remove_all<XprType>::type&
nestedExpression() const { return m_xpr; }
/** \returns the nested expression */
typename internal::remove_reference<XprType>::type&
nestedExpression() { return m_xpr; }
/** \returns a const reference to the object storing/generating the row indices */
const RowIndices& rowIndices() const { return m_rowIndices; }
/** \returns a const reference to the object storing/generating the column indices */
const ColIndices& colIndices() const { return m_colIndices; }
protected:
MatrixTypeNested m_xpr;
RowIndices m_rowIndices;
ColIndices m_colIndices;
};
// Generic API dispatcher
template<typename XprType, typename RowIndices, typename ColIndices, typename StorageKind>
class IndexedViewImpl
: public internal::generic_xpr_base<IndexedView<XprType, RowIndices, ColIndices> >::type
{
public:
typedef typename internal::generic_xpr_base<IndexedView<XprType, RowIndices, ColIndices> >::type Base;
};
namespace internal {
template<typename ArgType, typename RowIndices, typename ColIndices>
struct unary_evaluator<IndexedView<ArgType, RowIndices, ColIndices>, IndexBased>
: evaluator_base<IndexedView<ArgType, RowIndices, ColIndices> >
{
typedef IndexedView<ArgType, RowIndices, ColIndices> XprType;
enum {
CoeffReadCost = evaluator<ArgType>::CoeffReadCost /* TODO + cost of row/col index */,
FlagsLinearAccessBit = (traits<XprType>::RowsAtCompileTime == 1 || traits<XprType>::ColsAtCompileTime == 1) ? LinearAccessBit : 0,
FlagsRowMajorBit = traits<XprType>::FlagsRowMajorBit,
Flags = (evaluator<ArgType>::Flags & (HereditaryBits & ~RowMajorBit /*| LinearAccessBit | DirectAccessBit*/)) | FlagsLinearAccessBit | FlagsRowMajorBit,
Alignment = 0
};
EIGEN_DEVICE_FUNC explicit unary_evaluator(const XprType& xpr) : m_argImpl(xpr.nestedExpression()), m_xpr(xpr)
{
EIGEN_INTERNAL_CHECK_COST_VALUE(CoeffReadCost);
}
typedef typename XprType::Scalar Scalar;
typedef typename XprType::CoeffReturnType CoeffReturnType;
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
CoeffReturnType coeff(Index row, Index col) const
{
return m_argImpl.coeff(m_xpr.rowIndices()[row], m_xpr.colIndices()[col]);
}
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
Scalar& coeffRef(Index row, Index col)
{
return m_argImpl.coeffRef(m_xpr.rowIndices()[row], m_xpr.colIndices()[col]);
}
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
Scalar& coeffRef(Index index)
{
EIGEN_STATIC_ASSERT_LVALUE(XprType)
Index row = XprType::RowsAtCompileTime == 1 ? 0 : index;
Index col = XprType::RowsAtCompileTime == 1 ? index : 0;
return m_argImpl.coeffRef( m_xpr.rowIndices()[row], m_xpr.colIndices()[col]);
}
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
const Scalar& coeffRef(Index index) const
{
Index row = XprType::RowsAtCompileTime == 1 ? 0 : index;
Index col = XprType::RowsAtCompileTime == 1 ? index : 0;
return m_argImpl.coeffRef( m_xpr.rowIndices()[row], m_xpr.colIndices()[col]);
}
EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE
const CoeffReturnType coeff(Index index) const
{
Index row = XprType::RowsAtCompileTime == 1 ? 0 : index;
Index col = XprType::RowsAtCompileTime == 1 ? index : 0;
return m_argImpl.coeff( m_xpr.rowIndices()[row], m_xpr.colIndices()[col]);
}
protected:
evaluator<ArgType> m_argImpl;
const XprType& m_xpr;
};
} // end namespace internal
} // end namespace Eigen
#endif // EIGEN_INDEXED_VIEW_H