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Diffstat (limited to 'Eigen/src/Core/util/SymbolicIndex.h')
| -rw-r--r-- | Eigen/src/Core/util/SymbolicIndex.h | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/Eigen/src/Core/util/SymbolicIndex.h b/Eigen/src/Core/util/SymbolicIndex.h new file mode 100644 index 000000000..354dd9add --- /dev/null +++ b/Eigen/src/Core/util/SymbolicIndex.h @@ -0,0 +1,293 @@ +// 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_SYMBOLIC_INDEX_H +#define EIGEN_SYMBOLIC_INDEX_H + +namespace Eigen { + +/** \namespace Eigen::symbolic + * \ingroup Core_Module + * + * This namespace defines a set of classes and functions to build and evaluate symbolic expressions of scalar type Index. + * Here is a simple example: + * + * \code + * // First step, defines symbols: + * struct x_tag {}; static const symbolic::SymbolExpr<x_tag> x; + * struct y_tag {}; static const symbolic::SymbolExpr<y_tag> y; + * struct z_tag {}; static const symbolic::SymbolExpr<z_tag> z; + * + * // Defines an expression: + * auto expr = (x+3)/y+z; + * + * // And evaluate it: (c++14) + * std::cout << expr.eval(x=6,y=3,z=-13) << "\n"; + * + * // In c++98/11, only one symbol per expression is supported for now: + * auto expr98 = (3-x)/2; + * std::cout << expr98.eval(x=6) << "\n"; + * \endcode + * + * It is currently only used internally to define and manipulate the Eigen::last and Eigen::lastp1 symbols in Eigen::seq and Eigen::seqN. + * + */ +namespace symbolic { + +template<typename Tag> class Symbol; +template<typename Arg0> class NegateExpr; +template<typename Arg1,typename Arg2> class AddExpr; +template<typename Arg1,typename Arg2> class ProductExpr; +template<typename Arg1,typename Arg2> class QuotientExpr; + +// A simple wrapper around an integral value to provide the eval method. +// We could also use a free-function symbolic_eval... +template<typename IndexType=Index> +class ValueExpr { +public: + ValueExpr(IndexType val) : m_value(val) {} + template<typename T> + IndexType eval_impl(const T&) const { return m_value; } +protected: + IndexType m_value; +}; + +// Specialization for compile-time value, +// It is similar to ValueExpr(N) but this version helps the compiler to generate better code. +template<int N> +class ValueExpr<internal::FixedInt<N> > { +public: + ValueExpr() {} + template<typename T> + EIGEN_CONSTEXPR Index eval_impl(const T&) const { return N; } +}; + + +/** \class BaseExpr + * \ingroup Core_Module + * Common base class of any symbolic expressions + */ +template<typename Derived> +class BaseExpr +{ +public: + const Derived& derived() const { return *static_cast<const Derived*>(this); } + + /** Evaluate the expression given the \a values of the symbols. + * + * \param values defines the values of the symbols, it can either be a SymbolValue or a std::tuple of SymbolValue + * as constructed by SymbolExpr::operator= operator. + * + */ + template<typename T> + Index eval(const T& values) const { return derived().eval_impl(values); } + +#if EIGEN_HAS_CXX14 + template<typename... Types> + Index eval(Types&&... values) const { return derived().eval_impl(std::make_tuple(values...)); } +#endif + + NegateExpr<Derived> operator-() const { return NegateExpr<Derived>(derived()); } + + AddExpr<Derived,ValueExpr<> > operator+(Index b) const + { return AddExpr<Derived,ValueExpr<> >(derived(), b); } + AddExpr<Derived,ValueExpr<> > operator-(Index a) const + { return AddExpr<Derived,ValueExpr<> >(derived(), -a); } + ProductExpr<Derived,ValueExpr<> > operator*(Index a) const + { return ProductExpr<Derived,ValueExpr<> >(derived(),a); } + QuotientExpr<Derived,ValueExpr<> > operator/(Index a) const + { return QuotientExpr<Derived,ValueExpr<> >(derived(),a); } + + friend AddExpr<Derived,ValueExpr<> > operator+(Index a, const BaseExpr& b) + { return AddExpr<Derived,ValueExpr<> >(b.derived(), a); } + friend AddExpr<NegateExpr<Derived>,ValueExpr<> > operator-(Index a, const BaseExpr& b) + { return AddExpr<NegateExpr<Derived>,ValueExpr<> >(-b.derived(), a); } + friend ProductExpr<ValueExpr<>,Derived> operator*(Index a, const BaseExpr& b) + { return ProductExpr<ValueExpr<>,Derived>(a,b.derived()); } + friend QuotientExpr<ValueExpr<>,Derived> operator/(Index a, const BaseExpr& b) + { return QuotientExpr<ValueExpr<>,Derived>(a,b.derived()); } + + template<int N> + AddExpr<Derived,ValueExpr<internal::FixedInt<N> > > operator+(internal::FixedInt<N>) const + { return AddExpr<Derived,ValueExpr<internal::FixedInt<N> > >(derived(), ValueExpr<internal::FixedInt<N> >()); } + template<int N> + AddExpr<Derived,ValueExpr<internal::FixedInt<-N> > > operator-(internal::FixedInt<N>) const + { return AddExpr<Derived,ValueExpr<internal::FixedInt<-N> > >(derived(), ValueExpr<internal::FixedInt<-N> >()); } + template<int N> + ProductExpr<Derived,ValueExpr<internal::FixedInt<N> > > operator*(internal::FixedInt<N>) const + { return ProductExpr<Derived,ValueExpr<internal::FixedInt<N> > >(derived(),ValueExpr<internal::FixedInt<N> >()); } + template<int N> + QuotientExpr<Derived,ValueExpr<internal::FixedInt<N> > > operator/(internal::FixedInt<N>) const + { return QuotientExpr<Derived,ValueExpr<internal::FixedInt<N> > >(derived(),ValueExpr<internal::FixedInt<N> >()); } + + template<int N> + friend AddExpr<Derived,ValueExpr<internal::FixedInt<N> > > operator+(internal::FixedInt<N>, const BaseExpr& b) + { return AddExpr<Derived,ValueExpr<internal::FixedInt<N> > >(b.derived(), ValueExpr<internal::FixedInt<N> >()); } + template<int N> + friend AddExpr<NegateExpr<Derived>,ValueExpr<internal::FixedInt<N> > > operator-(internal::FixedInt<N>, const BaseExpr& b) + { return AddExpr<NegateExpr<Derived>,ValueExpr<internal::FixedInt<N> > >(-b.derived(), ValueExpr<internal::FixedInt<N> >()); } + template<int N> + friend ProductExpr<ValueExpr<internal::FixedInt<N> >,Derived> operator*(internal::FixedInt<N>, const BaseExpr& b) + { return ProductExpr<ValueExpr<internal::FixedInt<N> >,Derived>(ValueExpr<internal::FixedInt<N> >(),b.derived()); } + template<int N> + friend QuotientExpr<ValueExpr<internal::FixedInt<N> >,Derived> operator/(internal::FixedInt<N>, const BaseExpr& b) + { return QuotientExpr<ValueExpr<internal::FixedInt<N> > ,Derived>(ValueExpr<internal::FixedInt<N> >(),b.derived()); } + +#if (!EIGEN_HAS_CXX14) + template<int N> + AddExpr<Derived,ValueExpr<internal::FixedInt<N> > > operator+(internal::FixedInt<N> (*)()) const + { return AddExpr<Derived,ValueExpr<internal::FixedInt<N> > >(derived(), ValueExpr<internal::FixedInt<N> >()); } + template<int N> + AddExpr<Derived,ValueExpr<internal::FixedInt<-N> > > operator-(internal::FixedInt<N> (*)()) const + { return AddExpr<Derived,ValueExpr<internal::FixedInt<-N> > >(derived(), ValueExpr<internal::FixedInt<-N> >()); } + template<int N> + ProductExpr<Derived,ValueExpr<internal::FixedInt<N> > > operator*(internal::FixedInt<N> (*)()) const + { return ProductExpr<Derived,ValueExpr<internal::FixedInt<N> > >(derived(),ValueExpr<internal::FixedInt<N> >()); } + template<int N> + QuotientExpr<Derived,ValueExpr<internal::FixedInt<N> > > operator/(internal::FixedInt<N> (*)()) const + { return QuotientExpr<Derived,ValueExpr<internal::FixedInt<N> > >(derived(),ValueExpr<internal::FixedInt<N> >()); } + + template<int N> + friend AddExpr<Derived,ValueExpr<internal::FixedInt<N> > > operator+(internal::FixedInt<N> (*)(), const BaseExpr& b) + { return AddExpr<Derived,ValueExpr<internal::FixedInt<N> > >(b.derived(), ValueExpr<internal::FixedInt<N> >()); } + template<int N> + friend AddExpr<NegateExpr<Derived>,ValueExpr<internal::FixedInt<N> > > operator-(internal::FixedInt<N> (*)(), const BaseExpr& b) + { return AddExpr<NegateExpr<Derived>,ValueExpr<internal::FixedInt<N> > >(-b.derived(), ValueExpr<internal::FixedInt<N> >()); } + template<int N> + friend ProductExpr<ValueExpr<internal::FixedInt<N> >,Derived> operator*(internal::FixedInt<N> (*)(), const BaseExpr& b) + { return ProductExpr<ValueExpr<internal::FixedInt<N> >,Derived>(ValueExpr<internal::FixedInt<N> >(),b.derived()); } + template<int N> + friend QuotientExpr<ValueExpr<internal::FixedInt<N> >,Derived> operator/(internal::FixedInt<N> (*)(), const BaseExpr& b) + { return QuotientExpr<ValueExpr<internal::FixedInt<N> > ,Derived>(ValueExpr<internal::FixedInt<N> >(),b.derived()); } +#endif + + + template<typename OtherDerived> + AddExpr<Derived,OtherDerived> operator+(const BaseExpr<OtherDerived> &b) const + { return AddExpr<Derived,OtherDerived>(derived(), b.derived()); } + + template<typename OtherDerived> + AddExpr<Derived,NegateExpr<OtherDerived> > operator-(const BaseExpr<OtherDerived> &b) const + { return AddExpr<Derived,NegateExpr<OtherDerived> >(derived(), -b.derived()); } + + template<typename OtherDerived> + ProductExpr<Derived,OtherDerived> operator*(const BaseExpr<OtherDerived> &b) const + { return ProductExpr<Derived,OtherDerived>(derived(), b.derived()); } + + template<typename OtherDerived> + QuotientExpr<Derived,OtherDerived> operator/(const BaseExpr<OtherDerived> &b) const + { return QuotientExpr<Derived,OtherDerived>(derived(), b.derived()); } +}; + +template<typename T> +struct is_symbolic { + // BaseExpr has no conversion ctor, so we only have to check whether T can be statically cast to its base class BaseExpr<T>. + enum { value = internal::is_convertible<T,BaseExpr<T> >::value }; +}; + +/** Represents the actual value of a symbol identified by its tag + * + * It is the return type of SymbolValue::operator=, and most of the time this is only way it is used. + */ +template<typename Tag> +class SymbolValue +{ +public: + /** Default constructor from the value \a val */ + SymbolValue(Index val) : m_value(val) {} + + /** \returns the stored value of the symbol */ + Index value() const { return m_value; } +protected: + Index m_value; +}; + +/** Expression of a symbol uniquely identified by the template parameter type \c tag */ +template<typename tag> +class SymbolExpr : public BaseExpr<SymbolExpr<tag> > +{ +public: + /** Alias to the template parameter \c tag */ + typedef tag Tag; + + SymbolExpr() {} + + /** Associate the value \a val to the given symbol \c *this, uniquely identified by its \c Tag. + * + * The returned object should be passed to ExprBase::eval() to evaluate a given expression with this specified runtime-time value. + */ + SymbolValue<Tag> operator=(Index val) const { + return SymbolValue<Tag>(val); + } + + Index eval_impl(const SymbolValue<Tag> &values) const { return values.value(); } + +#if EIGEN_HAS_CXX14 + // C++14 versions suitable for multiple symbols + template<typename... Types> + Index eval_impl(const std::tuple<Types...>& values) const { return std::get<SymbolValue<Tag> >(values).value(); } +#endif +}; + +template<typename Arg0> +class NegateExpr : public BaseExpr<NegateExpr<Arg0> > +{ +public: + NegateExpr(const Arg0& arg0) : m_arg0(arg0) {} + + template<typename T> + Index eval_impl(const T& values) const { return -m_arg0.eval_impl(values); } +protected: + Arg0 m_arg0; +}; + +template<typename Arg0, typename Arg1> +class AddExpr : public BaseExpr<AddExpr<Arg0,Arg1> > +{ +public: + AddExpr(const Arg0& arg0, const Arg1& arg1) : m_arg0(arg0), m_arg1(arg1) {} + + template<typename T> + Index eval_impl(const T& values) const { return m_arg0.eval_impl(values) + m_arg1.eval_impl(values); } +protected: + Arg0 m_arg0; + Arg1 m_arg1; +}; + +template<typename Arg0, typename Arg1> +class ProductExpr : public BaseExpr<ProductExpr<Arg0,Arg1> > +{ +public: + ProductExpr(const Arg0& arg0, const Arg1& arg1) : m_arg0(arg0), m_arg1(arg1) {} + + template<typename T> + Index eval_impl(const T& values) const { return m_arg0.eval_impl(values) * m_arg1.eval_impl(values); } +protected: + Arg0 m_arg0; + Arg1 m_arg1; +}; + +template<typename Arg0, typename Arg1> +class QuotientExpr : public BaseExpr<QuotientExpr<Arg0,Arg1> > +{ +public: + QuotientExpr(const Arg0& arg0, const Arg1& arg1) : m_arg0(arg0), m_arg1(arg1) {} + + template<typename T> + Index eval_impl(const T& values) const { return m_arg0.eval_impl(values) / m_arg1.eval_impl(values); } +protected: + Arg0 m_arg0; + Arg1 m_arg1; +}; + +} // end namespace symbolic + +} // end namespace Eigen + +#endif // EIGEN_SYMBOLIC_INDEX_H |