mirror of
https://github.com/triqs/dft_tools
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101 lines
3.5 KiB
C++
101 lines
3.5 KiB
C++
/*******************************************************************************
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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 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_ARRAYS_RANGE_H
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#define TRIQS_ARRAYS_RANGE_H
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#include <triqs/utility/first_include.hpp>
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#include <ostream>
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#include <boost/iterator/iterator_facade.hpp>
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namespace triqs {
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namespace arrays {
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/**
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*/
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class range {
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std::ptrdiff_t first_, last_, step_;
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public:
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typedef std::ptrdiff_t index_type;
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range() : first_(0), last_(-1), step_(1) {} // i.e. all
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range(const range& r) : first_(r.first_), last_(r.last_), step_(r.step_) {}
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range(std::ptrdiff_t first__, std::ptrdiff_t last__, std::ptrdiff_t step__ = 1)
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: first_(first__), last_(last__), step_(step__) {}
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range(std::ptrdiff_t i) : range (i,i+1,1){}
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std::ptrdiff_t first() const { return first_; }
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std::ptrdiff_t last() const { return last_; }
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std::ptrdiff_t step() const { return step_; }
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size_t size() const {
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std::ptrdiff_t r = (last_ - first_ + 1) / step_;
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if (r < 0) TRIQS_RUNTIME_ERROR << " range with negative size";
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return size_t(r);
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}
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range operator+(std::ptrdiff_t shift) const { return range(first_ + shift, last_ + shift, step_); }
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friend inline std::ostream& operator<<(std::ostream& os, const range& range) {
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os << "range(" << range.first() << "," << range.last() << "," << range.step() << ")";
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return os;
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}
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class const_iterator : public boost::iterator_facade<const_iterator, const std::ptrdiff_t, boost::forward_traversal_tag, const std::ptrdiff_t> {
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public:
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const_iterator(range const* r, bool atEnd) {
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last = r->last();
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pos = (atEnd ? last : r->first());
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}
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private:
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std::ptrdiff_t last, pos;
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friend class boost::iterator_core_access;
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void increment() { ++pos; }
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bool equal(const_iterator const& other) const { return (other.pos == pos); }
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std::ptrdiff_t dereference() const { return pos; }
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};
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const_iterator begin() const { return const_iterator(this, false); }
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const_iterator end() const { return const_iterator(this, true); }
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const_iterator cbegin() const { return const_iterator(this,false); }
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const_iterator cend() const { return const_iterator(this, true); }
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};
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// foreach
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template <typename F> void foreach(range const& r, F const& f) {
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std::ptrdiff_t i = r.first(), last = r.last(), step = r.step();
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for (; i < last; i += step) f(i);
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}
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/**
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*/
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class ellipsis : public range {
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public:
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ellipsis(std::ptrdiff_t first__, std::ptrdiff_t last__, std::ptrdiff_t step__ = 1) : range(first__, last__, step__) {}
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ellipsis() : range() {}
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};
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// for the case A(i, ellipsis) where A is of dim 1...
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inline int operator*(ellipsis, int) { return 0; }
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inline int operator*(int, ellipsis) { return 0; }
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}
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} // namespace triqs::arrays
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#endif
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