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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_HELPER_H
#define EIGEN_INDEXED_VIEW_HELPER_H
// IWYU pragma: private
#include "../InternalHeaderCheck.h"
namespace Eigen {
namespace internal {
struct symbolic_last_tag {};
struct all_t {};
} // namespace internal
namespace placeholders {
typedef symbolic::SymbolExpr<internal::symbolic_last_tag> last_t;
/** \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::placeholders::last;
* VectorXd v(n);
* v(seq(2,last-2)).setOnes();
* \endcode
*
* \sa end
*/
static constexpr const last_t last;
typedef symbolic::AddExpr<symbolic::SymbolExpr<internal::symbolic_last_tag>,
symbolic::ValueExpr<Eigen::internal::FixedInt<1>>>
lastp1_t;
typedef Eigen::internal::all_t all_t;
/** \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 constexpr 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 constexpr lastp1_t lastp1(last + fix<1>());
#endif
/** \var end
* \ingroup Core_Module
* \sa lastp1
*/
static constexpr lastp1_t end = lastp1;
/** \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 constexpr Eigen::internal::all_t all;
} // namespace placeholders
namespace internal {
// Evaluate a symbolic expression or constant given the "size" of an object, allowing
// any symbols like `last` to be evaluated. The default here assumes a dynamic constant.
template <typename Expr, int SizeAtCompileTime, typename EnableIf = void>
struct SymbolicExpressionEvaluator {
static constexpr Index ValueAtCompileTime = Undefined;
static Index eval(const Expr& expr, Index /*size*/) { return static_cast<Index>(expr); }
};
// Symbolic expression with size known at compile-time.
template <typename Expr, int SizeAtCompileTime>
struct SymbolicExpressionEvaluator<Expr, SizeAtCompileTime, std::enable_if_t<symbolic::is_symbolic<Expr>::value>> {
static constexpr Index ValueAtCompileTime =
Expr::Derived::eval_at_compile_time(Eigen::placeholders::last = fix<SizeAtCompileTime - 1>);
static Index eval(const Expr& expr, Index /*size*/) {
return expr.eval(Eigen::placeholders::last = fix<SizeAtCompileTime - 1>);
}
};
// Symbolic expression with dynamic size.
template <typename Expr>
struct SymbolicExpressionEvaluator<Expr, Dynamic, std::enable_if_t<symbolic::is_symbolic<Expr>::value>> {
static constexpr Index ValueAtCompileTime = Undefined;
static Index eval(const Expr& expr, Index size) { return expr.eval(Eigen::placeholders::last = size - 1); }
};
// Fixed int.
template <int N, int SizeAtCompileTime>
struct SymbolicExpressionEvaluator<FixedInt<N>, SizeAtCompileTime, void> {
static constexpr Index ValueAtCompileTime = static_cast<Index>(N);
static Index eval(const FixedInt<N>& /*expr*/, Index /*size*/) { return ValueAtCompileTime; }
};
//--------------------------------------------------------------------------------
// Handling of generic indices (e.g. array)
//--------------------------------------------------------------------------------
// Potentially wrap indices in a type that is better-suited for IndexedView evaluation.
template <typename Indices, int NestedSizeAtCompileTime, typename EnableIf = void>
struct IndexedViewHelperIndicesWrapper {
using type = Indices;
static const type& CreateIndexSequence(const Indices& indices, Index /*nested_size*/) { return indices; }
};
// Extract compile-time and runtime first, size, increments.
template <typename Indices, typename EnableIf = void>
struct IndexedViewHelper {
static constexpr Index FirstAtCompileTime = Undefined;
static constexpr Index SizeAtCompileTime = array_size<Indices>::value;
static constexpr Index IncrAtCompileTime = Undefined;
static constexpr Index first(const Indices& indices) { return static_cast<Index>(indices[0]); }
static constexpr Index size(const Indices& indices) { return index_list_size(indices); }
static constexpr Index incr(const Indices& /*indices*/) { return Undefined; }
};
//--------------------------------------------------------------------------------
// Handling of ArithmeticSequence
//--------------------------------------------------------------------------------
template <Index FirstAtCompileTime_, Index SizeAtCompileTime_, Index IncrAtCompileTime_>
class ArithmeticSequenceRange {
public:
static constexpr Index FirstAtCompileTime = FirstAtCompileTime_;
static constexpr Index SizeAtCompileTime = SizeAtCompileTime_;
static constexpr Index IncrAtCompileTime = IncrAtCompileTime_;
constexpr ArithmeticSequenceRange(Index first, Index size, Index incr) : first_{first}, size_{size}, incr_{incr} {}
constexpr Index operator[](Index i) const { return first() + i * incr(); }
constexpr Index first() const noexcept { return first_.value(); }
constexpr Index size() const noexcept { return size_.value(); }
constexpr Index incr() const noexcept { return incr_.value(); }
private:
variable_if_dynamicindex<Index, int(FirstAtCompileTime)> first_;
variable_if_dynamic<Index, int(SizeAtCompileTime)> size_;
variable_if_dynamicindex<Index, int(IncrAtCompileTime)> incr_;
};
template <typename FirstType, typename SizeType, typename IncrType, int NestedSizeAtCompileTime>
struct IndexedViewHelperIndicesWrapper<ArithmeticSequence<FirstType, SizeType, IncrType>, NestedSizeAtCompileTime,
void> {
static constexpr Index EvalFirstAtCompileTime =
SymbolicExpressionEvaluator<FirstType, NestedSizeAtCompileTime>::ValueAtCompileTime;
static constexpr Index EvalSizeAtCompileTime =
SymbolicExpressionEvaluator<SizeType, NestedSizeAtCompileTime>::ValueAtCompileTime;
static constexpr Index EvalIncrAtCompileTime =
SymbolicExpressionEvaluator<IncrType, NestedSizeAtCompileTime>::ValueAtCompileTime;
static constexpr Index FirstAtCompileTime =
(int(EvalFirstAtCompileTime) == Undefined) ? Index(DynamicIndex) : EvalFirstAtCompileTime;
static constexpr Index SizeAtCompileTime =
(int(EvalSizeAtCompileTime) == Undefined) ? Index(Dynamic) : EvalSizeAtCompileTime;
static constexpr Index IncrAtCompileTime =
(int(EvalIncrAtCompileTime) == Undefined) ? Index(DynamicIndex) : EvalIncrAtCompileTime;
using Indices = ArithmeticSequence<FirstType, SizeType, IncrType>;
using type = ArithmeticSequenceRange<FirstAtCompileTime, SizeAtCompileTime, IncrAtCompileTime>;
static type CreateIndexSequence(const Indices& indices, Index nested_size) {
Index first =
SymbolicExpressionEvaluator<FirstType, NestedSizeAtCompileTime>::eval(indices.firstObject(), nested_size);
Index size =
SymbolicExpressionEvaluator<SizeType, NestedSizeAtCompileTime>::eval(indices.sizeObject(), nested_size);
Index incr =
SymbolicExpressionEvaluator<IncrType, NestedSizeAtCompileTime>::eval(indices.incrObject(), nested_size);
return type(first, size, incr);
}
};
template <Index FirstAtCompileTime_, Index SizeAtCompileTime_, Index IncrAtCompileTime_>
struct IndexedViewHelper<ArithmeticSequenceRange<FirstAtCompileTime_, SizeAtCompileTime_, IncrAtCompileTime_>, void> {
public:
using Indices = ArithmeticSequenceRange<FirstAtCompileTime_, SizeAtCompileTime_, IncrAtCompileTime_>;
static constexpr Index FirstAtCompileTime = Indices::FirstAtCompileTime;
static constexpr Index SizeAtCompileTime = Indices::SizeAtCompileTime;
static constexpr Index IncrAtCompileTime = Indices::IncrAtCompileTime;
static Index first(const Indices& indices) { return indices.first(); }
static Index size(const Indices& indices) { return indices.size(); }
static Index incr(const Indices& indices) { return indices.incr(); }
};
//--------------------------------------------------------------------------------
// Handling of a single index.
//--------------------------------------------------------------------------------
template <Index ValueAtCompileTime>
class SingleRange {
public:
static constexpr Index FirstAtCompileTime = ValueAtCompileTime;
static constexpr Index SizeAtCompileTime = Index(1);
static constexpr Index IncrAtCompileTime = Index(1); // Needs to be 1 to be treated as block-like.
constexpr SingleRange(Index v) noexcept : value_(v) {}
constexpr Index operator[](Index) const noexcept { return first(); }
constexpr Index first() const noexcept { return value_.value(); }
constexpr Index size() const noexcept { return SizeAtCompileTime; }
constexpr Index incr() const noexcept { return IncrAtCompileTime; }
private:
variable_if_dynamicindex<Index, int(ValueAtCompileTime)> value_;
};
template <typename T>
struct is_single_range : public std::false_type {};
template <Index ValueAtCompileTime>
struct is_single_range<SingleRange<ValueAtCompileTime>> : public std::true_type {};
template <typename SingleIndex, int NestedSizeAtCompileTime>
struct IndexedViewHelperIndicesWrapper<
SingleIndex, NestedSizeAtCompileTime,
std::enable_if_t<std::is_integral<SingleIndex>::value || symbolic::is_symbolic<SingleIndex>::value>> {
static constexpr Index EvalValueAtCompileTime =
SymbolicExpressionEvaluator<SingleIndex, NestedSizeAtCompileTime>::ValueAtCompileTime;
static constexpr Index ValueAtCompileTime =
(int(EvalValueAtCompileTime) == Undefined) ? Index(DynamicIndex) : EvalValueAtCompileTime;
using type = SingleRange<ValueAtCompileTime>;
static type CreateIndexSequence(const SingleIndex& index, Index nested_size) {
return type(SymbolicExpressionEvaluator<SingleIndex, NestedSizeAtCompileTime>::eval(index, nested_size));
}
};
template <int N, int NestedSizeAtCompileTime>
struct IndexedViewHelperIndicesWrapper<FixedInt<N>, NestedSizeAtCompileTime, void> {
using type = SingleRange<Index(N)>;
static type CreateIndexSequence(const FixedInt<N>& /*index*/) { return type(Index(N)); }
};
template <Index ValueAtCompileTime>
struct IndexedViewHelper<SingleRange<ValueAtCompileTime>, void> {
using Indices = SingleRange<ValueAtCompileTime>;
static constexpr Index FirstAtCompileTime = Indices::FirstAtCompileTime;
static constexpr Index SizeAtCompileTime = Indices::SizeAtCompileTime;
static constexpr Index IncrAtCompileTime = Indices::IncrAtCompileTime;
static constexpr Index first(const Indices& indices) { return indices.first(); }
static constexpr Index size(const Indices& /*indices*/) { return SizeAtCompileTime; }
static constexpr Index incr(const Indices& /*indices*/) { return IncrAtCompileTime; }
};
//--------------------------------------------------------------------------------
// Handling of all
//--------------------------------------------------------------------------------
// Convert a symbolic 'all' into a usable range type
template <Index SizeAtCompileTime_>
class AllRange {
public:
static constexpr Index FirstAtCompileTime = Index(0);
static constexpr Index SizeAtCompileTime = SizeAtCompileTime_;
static constexpr Index IncrAtCompileTime = Index(1);
constexpr AllRange(Index size) : size_(size) {}
constexpr Index operator[](Index i) const noexcept { return i; }
constexpr Index first() const noexcept { return FirstAtCompileTime; }
constexpr Index size() const noexcept { return size_.value(); }
constexpr Index incr() const noexcept { return IncrAtCompileTime; }
private:
variable_if_dynamic<Index, int(SizeAtCompileTime)> size_;
};
template <int NestedSizeAtCompileTime>
struct IndexedViewHelperIndicesWrapper<all_t, NestedSizeAtCompileTime, void> {
using type = AllRange<Index(NestedSizeAtCompileTime)>;
static type CreateIndexSequence(const all_t& /*indices*/, Index nested_size) { return type(nested_size); }
};
template <Index SizeAtCompileTime_>
struct IndexedViewHelper<AllRange<SizeAtCompileTime_>, void> {
using Indices = AllRange<SizeAtCompileTime_>;
static constexpr Index FirstAtCompileTime = Indices::FirstAtCompileTime;
static constexpr Index SizeAtCompileTime = Indices::SizeAtCompileTime;
static constexpr Index IncrAtCompileTime = Indices::IncrAtCompileTime;
static Index first(const Indices& indices) { return indices.first(); }
static Index size(const Indices& indices) { return indices.size(); }
static Index incr(const Indices& indices) { return indices.incr(); }
};
} // end namespace internal
} // end namespace Eigen
#endif // EIGEN_INDEXED_VIEW_HELPER_H