mirror of
https://github.com/triqs/dft_tools
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91 lines
3.3 KiB
C++
91 lines
3.3 KiB
C++
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/*******************************************************************************
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*
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* TRIQS: a Toolbox for Research in Interacting Quantum Systems
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*
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* Copyright (C) 2011 by M. Ferrero, O. Parcollet
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*
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* TRIQS is free software: you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* TRIQS. If not, see <http://www.gnu.org/licenses/>.
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*
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******************************************************************************/
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#ifndef TRIQS_LATTICE_FUNCTORS_H
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#define TRIQS_LATTICE_FUNCTORS_H
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namespace triqs { namespace lattice_tools {
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const double pi = acos(-1.0);
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const std::complex<double> I(0,1);
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template<typename F> struct minus_chech_impl {
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typedef typename F::arg_type arg_type;
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typedef typename F::return_type return_type;
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F f;
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minus_chech_impl(F const & f_):f(f_){}
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brillouin_zone const & bz() const {return f.bz();}
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return_type operator()(arg_type const & x) const { return_type res(f(x)); res *=-1; return res;}
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};
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namespace result_of { template<typename F> struct minus_chech{ typedef minus_chech_impl<F> type;}; }
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/**
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* Given f of type F which models FunctionOnBravaisLattice, minus_check(f) :
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* - returns -f(-args)
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* - its type models Function
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*
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*/
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template<typename F> minus_chech_impl<F> minus_chech(F const & f) { return minus_chech_impl<F> (f);}
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template<typename F >//, typename Enabler = boost::enable_if< Tag::check<Tag::ShortRangeFunctionOnBravaisLattice, F> > >
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class fourier_impl {
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F f;
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brillouin_zone bz_;
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// deduce the return type from decltype(begin()->second)
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public:
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typedef typename non_view_type_if_exists_else_type< decltype(f.begin()->second)>::type return_construct_type;
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typedef typename view_type_if_exists_else_type<return_construct_type>::type return_type;
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typedef K_view_type arg_type;
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fourier_impl (F f_):f(f_), bz_(f_.lattice()), res(f.n_bands(),f.n_bands()) {}
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//brillouin_zone const & bz() const { return bz_; }
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return_type operator()(K_view_type const & k) {
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res()=0;
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for (auto const & pdm : f) { res += pdm.second * exp( 2*pi*I* this->dot_product(k,pdm.first)); }
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return res;
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}
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protected:
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inline double dot_product(K_view_type const & a, typename F::arg_type const & b) const {
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assert(b.size()>= this->bz_.lattice().dim());
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double r=0; for (size_t i=0; i< this->bz_.lattice().dim();++i) r += a(i) * b[i];
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return r;
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}
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return_construct_type res;
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//typename F::return_construct_type res;
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};
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/**
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* Given f of type F which models ShortRangeFunctionOnBravaisLattice, Fourier(f) returns
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* - a type that models FunctionOnBravaisLattice
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* - and returns the Fourier transform f(k)
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*/
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template<typename F> fourier_impl<F> Fourier(F f) { return fourier_impl<F> (f);}
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//namespace result_of { template<typename F> struct Fourier { typedef fourier_impl<F> type;}; }
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}}
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#endif
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