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dft_tools/triqs/utility/arithmetic_ops_by_cast.hpp

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/*******************************************************************************
*
* TRIQS: a Toolbox for Research in Interacting Quantum Systems
*
* Copyright (C) 2013 by O. Parcollet
*
* TRIQS is free software: you can redistribute it and/or modify it under the
* terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
*
* TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* TRIQS. If not, see <http://www.gnu.org/licenses/>.
*
******************************************************************************/
#pragma once
namespace triqs {
namespace utility {
// Derive from this object using CRTP to provide arithmetic operation by casting the final object to C
// by not forwarding x, I assume the cast is a simple value, not a matrix, but this is ok
template <typename Derived, typename C> struct arithmetic_ops_by_cast {};
#define IMPL_OP(OP) \
template <typename D, typename C, typename Y> \
auto operator OP(arithmetic_ops_by_cast<D, C> const &x, Y &&y)->decltype(std::declval<C>() OP std::forward<Y>(y)) { \
return C(static_cast<D const &>(x)) OP std::forward<Y>(y); \
} \
template <typename D, typename C, typename Y> \
auto operator OP(Y &&y, arithmetic_ops_by_cast<D, C> const &x) \
->TYPE_DISABLE_IF(decltype(std::forward<Y>(y) OP std::declval<C>()), \
std::is_base_of<D, typename std::remove_cv<typename std::remove_reference<Y>::type>::type>) { \
return std::forward<Y>(y) OP C(static_cast<D const &>(x)); \
}
IMPL_OP(+);
IMPL_OP(-);
IMPL_OP(*);
IMPL_OP(/ );
#undef IMPL_OP
// Same thing, but disallow the operations with the type itself
template <typename Derived, typename C> struct arithmetic_ops_by_cast_disable_same_type {};
#define IMPL_OP(OP) \
template <typename D, typename C, typename Y> \
auto operator OP(arithmetic_ops_by_cast_disable_same_type<D, C> const &x, Y &&y) \
->TYPE_DISABLE_IF(decltype(std::declval<C>() OP std::forward<Y>(y)), \
std::is_base_of<D, typename std::remove_cv<typename std::remove_reference<Y>::type>::type>) { \
return C(static_cast<D const &>(x)) OP std::forward<Y>(y); \
} \
template <typename D, typename C, typename Y> \
auto operator OP(Y &&y, arithmetic_ops_by_cast_disable_same_type<D, C> const &x) \
->TYPE_DISABLE_IF(decltype(std::forward<Y>(y) OP std::declval<C>()), \
std::is_base_of<D, typename std::remove_cv<typename std::remove_reference<Y>::type>::type>) { \
return std::forward<Y>(y) OP C(static_cast<D const &>(x)); \
}
IMPL_OP(+);
IMPL_OP(-);
IMPL_OP(*);
IMPL_OP(/ );
#undef IMPL_OP
}
}