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Diffstat (limited to 'Eigen/src/Core/util/IndexedViewHelper.h')
-rw-r--r-- | Eigen/src/Core/util/IndexedViewHelper.h | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/Eigen/src/Core/util/IndexedViewHelper.h b/Eigen/src/Core/util/IndexedViewHelper.h new file mode 100644 index 000000000..f85de305f --- /dev/null +++ b/Eigen/src/Core/util/IndexedViewHelper.h @@ -0,0 +1,186 @@ +// 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_HELPER_H +#define EIGEN_INDEXED_VIEW_HELPER_H + +namespace Eigen { + +namespace internal { +struct symbolic_last_tag {}; +} + +/** \var last + * \ingroup Core_Module + * + * Can be used as a parameter to Eigen::seq and Eigen::seqN functions to symbolically reference the last element/row/columns + * of the underlying vector or matrix once passed to DenseBase::operator()(const RowIndices&, const ColIndices&). + * + * This symbolic placeholder supports standard arithmetic operations. + * + * A typical usage example would be: + * \code + * using namespace Eigen; + * using Eigen::last; + * VectorXd v(n); + * v(seq(2,last-2)).setOnes(); + * \endcode + * + * \sa end + */ +static const symbolic::SymbolExpr<internal::symbolic_last_tag> last; // PLEASE use Eigen::last instead of Eigen::placeholders::last + +/** \var lastp1 + * \ingroup Core_Module + * + * Can be used as a parameter to Eigen::seq and Eigen::seqN functions to symbolically + * reference the last+1 element/row/columns of the underlying vector or matrix once + * passed to DenseBase::operator()(const RowIndices&, const ColIndices&). + * + * This symbolic placeholder supports standard arithmetic operations. + * It is essentially an alias to last+fix<1>. + * + * \sa last + */ +#ifdef EIGEN_PARSED_BY_DOXYGEN +static const auto lastp1 = last+fix<1>; +#else +// Using a FixedExpr<1> expression is important here to make sure the compiler +// can fully optimize the computation starting indices with zero overhead. +static const symbolic::AddExpr<symbolic::SymbolExpr<internal::symbolic_last_tag>,symbolic::ValueExpr<Eigen::internal::FixedInt<1> > > lastp1(last+fix<1>()); +#endif + +namespace internal { + + // Replace symbolic last/end "keywords" by their true runtime value +inline Index eval_expr_given_size(Index x, Index /* size */) { return x; } + +template<int N> +FixedInt<N> eval_expr_given_size(FixedInt<N> x, Index /*size*/) { return x; } + +template<typename Derived> +Index eval_expr_given_size(const symbolic::BaseExpr<Derived> &x, Index size) +{ + return x.derived().eval(last=size-1); +} + +// Extract increment/step at compile time +template<typename T, typename EnableIf = void> struct get_compile_time_incr { + enum { value = UndefinedIncr }; +}; + +// Analogue of std::get<0>(x), but tailored for our needs. +template<typename T> +EIGEN_CONSTEXPR Index first(const T& x) EIGEN_NOEXCEPT { return x.first(); } + +// IndexedViewCompatibleType/makeIndexedViewCompatible turn an arbitrary object of type T into something usable by MatrixSlice +// The generic implementation is a no-op +template<typename T,int XprSize,typename EnableIf=void> +struct IndexedViewCompatibleType { + typedef T type; +}; + +template<typename T,typename Q> +const T& makeIndexedViewCompatible(const T& x, Index /*size*/, Q) { return x; } + +//-------------------------------------------------------------------------------- +// Handling of a single Index +//-------------------------------------------------------------------------------- + +struct SingleRange { + enum { + SizeAtCompileTime = 1 + }; + SingleRange(Index val) : m_value(val) {} + Index operator[](Index) const { return m_value; } + static EIGEN_CONSTEXPR Index size() EIGEN_NOEXCEPT { return 1; } + Index first() const EIGEN_NOEXCEPT { return m_value; } + Index m_value; +}; + +template<> struct get_compile_time_incr<SingleRange> { + enum { value = 1 }; // 1 or 0 ?? +}; + +// Turn a single index into something that looks like an array (i.e., that exposes a .size(), and operator[](int) methods) +template<typename T, int XprSize> +struct IndexedViewCompatibleType<T,XprSize,typename internal::enable_if<internal::is_integral<T>::value>::type> { + // Here we could simply use Array, but maybe it's less work for the compiler to use + // a simpler wrapper as SingleRange + //typedef Eigen::Array<Index,1,1> type; + typedef SingleRange type; +}; + +template<typename T, int XprSize> +struct IndexedViewCompatibleType<T, XprSize, typename enable_if<symbolic::is_symbolic<T>::value>::type> { + typedef SingleRange type; +}; + + +template<typename T> +typename enable_if<symbolic::is_symbolic<T>::value,SingleRange>::type +makeIndexedViewCompatible(const T& id, Index size, SpecializedType) { + return eval_expr_given_size(id,size); +} + +//-------------------------------------------------------------------------------- +// Handling of all +//-------------------------------------------------------------------------------- + +struct all_t { all_t() {} }; + +// Convert a symbolic 'all' into a usable range type +template<int XprSize> +struct AllRange { + enum { SizeAtCompileTime = XprSize }; + AllRange(Index size = XprSize) : m_size(size) {} + EIGEN_CONSTEXPR Index operator[](Index i) const EIGEN_NOEXCEPT { return i; } + EIGEN_CONSTEXPR Index size() const EIGEN_NOEXCEPT { return m_size.value(); } + EIGEN_CONSTEXPR Index first() const EIGEN_NOEXCEPT { return 0; } + variable_if_dynamic<Index,XprSize> m_size; +}; + +template<int XprSize> +struct IndexedViewCompatibleType<all_t,XprSize> { + typedef AllRange<XprSize> type; +}; + +template<typename XprSizeType> +inline AllRange<get_fixed_value<XprSizeType>::value> makeIndexedViewCompatible(all_t , XprSizeType size, SpecializedType) { + return AllRange<get_fixed_value<XprSizeType>::value>(size); +} + +template<int Size> struct get_compile_time_incr<AllRange<Size> > { + enum { value = 1 }; +}; + +} // end namespace internal + + +/** \var all + * \ingroup Core_Module + * Can be used as a parameter to DenseBase::operator()(const RowIndices&, const ColIndices&) to index all rows or columns + */ +static const Eigen::internal::all_t all; // PLEASE use Eigen::all instead of Eigen::placeholders::all + + +namespace placeholders { + typedef symbolic::SymbolExpr<internal::symbolic_last_tag> last_t; + typedef symbolic::AddExpr<symbolic::SymbolExpr<internal::symbolic_last_tag>,symbolic::ValueExpr<Eigen::internal::FixedInt<1> > > end_t; + typedef Eigen::internal::all_t all_t; + + EIGEN_DEPRECATED static const all_t all = Eigen::all; // PLEASE use Eigen::all instead of Eigen::placeholders::all + EIGEN_DEPRECATED static const last_t last = Eigen::last; // PLEASE use Eigen::last instead of Eigen::placeholders::last + EIGEN_DEPRECATED static const end_t end = Eigen::lastp1; // PLEASE use Eigen::lastp1 instead of Eigen::placeholders::end +} + +} // end namespace Eigen + +#endif // EIGEN_INDEXED_VIEW_HELPER_H |