Ifpack2 Templated Preconditioning Package Version 1.0
Ifpack2_Heap.hpp
00001 /*@HEADER
00002 // ***********************************************************************
00003 // 
00004 //       Ifpack2: Tempated Object-Oriented Algebraic Preconditioner Package
00005 //                 Copyright (2009) Sandia Corporation
00006 // 
00007 // Under terms of Contract DE-AC04-94AL85000, there is a non-exclusive
00008 // license for use of this work by or on behalf of the U.S. Government.
00009 // 
00010 // This library is free software; you can redistribute it and/or modify
00011 // it under the terms of the GNU Lesser General Public License as
00012 // published by the Free Software Foundation; either version 2.1 of the
00013 // License, or (at your option) any later version.
00014 //  
00015 // This library is distributed in the hope that it will be useful, but
00016 // WITHOUT ANY WARRANTY; without even the implied warranty of
00017 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00018 // Lesser General Public License for more details.
00019 //  
00020 // You should have received a copy of the GNU Lesser General Public
00021 // License along with this library; if not, write to the Free Software
00022 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
00023 // USA
00024 // Questions? Contact Michael A. Heroux (maherou@sandia.gov) 
00025 // 
00026 // ***********************************************************************
00027 //@HEADER
00028 */
00029 
00030 #ifndef IFPACK2_HEAP_HPP
00031 #define IFPACK2_HEAP_HPP
00032 
00033 #include <algorithm>
00034 #include "Teuchos_Array.hpp"
00035 
00036 namespace Ifpack2 {
00037 
00038 template<typename Scalar, typename Ordinal>
00039 struct greater_indirect {
00040   greater_indirect(const Teuchos::Array<Scalar>& vals)
00041   : m_vals(vals) {}
00042   ~greater_indirect(){}
00043 
00044   bool operator()(const Ordinal& lhs, const Ordinal& rhs) const
00045   { return Teuchos::ScalarTraits<Scalar>::magnitude(m_vals[lhs]) >
00046            Teuchos::ScalarTraits<Scalar>::magnitude(m_vals[rhs]); }
00047 
00048 private:
00049   const Teuchos::Array<Scalar>& m_vals;
00050 };//struct greater_indirect
00051 
00052 
00055 template<typename Ordinal, typename SizeType>
00056 void add_to_heap(const Ordinal& idx, Teuchos::Array<Ordinal>& heap, SizeType& heap_len)
00057 {
00058   if (heap.size() == heap_len) heap.push_back(idx);
00059   else heap[heap_len] = idx;
00060   ++heap_len;
00061   std::push_heap(heap.begin(), heap.begin()+heap_len, std::greater<Ordinal>());
00062 }
00063 
00067 template<typename Ordinal, typename SizeType, class Compare>
00068 void add_to_heap(const Ordinal& idx, Teuchos::Array<Ordinal>& heap, SizeType& heap_len, Compare comp)
00069 {
00070   if (heap.size() == heap_len) heap.push_back(idx);
00071   else heap[heap_len] = idx;
00072   ++heap_len;
00073   std::push_heap(heap.begin(), heap.begin()+heap_len, comp);
00074 }
00075 
00077 template<typename Ordinal, typename SizeType>
00078 void rm_heap_root(Teuchos::Array<Ordinal>& heap, SizeType& heap_len)
00079 {
00080   std::pop_heap(heap.begin(), heap.begin()+heap_len, std::greater<Ordinal>());
00081   --heap_len;
00082 }
00083 
00087 template<typename Ordinal, typename SizeType, class Compare>
00088 void rm_heap_root(Teuchos::Array<Ordinal>& heap, SizeType& heap_len, Compare comp)
00089 {
00090   std::pop_heap(heap.begin(), heap.begin()+heap_len, comp);
00091   --heap_len;
00092 }
00093 
00094 }//namespace Ifpack2
00095 
00096 #endif
00097 
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