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tree.hpp

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00001 /* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
00002 /*
00003  *  Main authors:
00004  *     Christian Schulte <schulte@gecode.org>
00005  *
00006  *  Copyright:
00007  *     Christian Schulte, 2009
00008  *
00009  *  Last modified:
00010  *     $Date: 2010-06-03 13:11:11 +0200 (Thu, 03 Jun 2010) $ by $Author: tack $
00011  *     $Revision: 11013 $
00012  *
00013  *  This file is part of Gecode, the generic constraint
00014  *  development environment:
00015  *     http://www.gecode.org
00016  *
00017  *  Permission is hereby granted, free of charge, to any person obtaining
00018  *  a copy of this software and associated documentation files (the
00019  *  "Software"), to deal in the Software without restriction, including
00020  *  without limitation the rights to use, copy, modify, merge, publish,
00021  *  distribute, sublicense, and/or sell copies of the Software, and to
00022  *  permit persons to whom the Software is furnished to do so, subject to
00023  *  the following conditions:
00024  *
00025  *  The above copyright notice and this permission notice shall be
00026  *  included in all copies or substantial portions of the Software.
00027  *
00028  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
00029  *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
00030  *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
00031  *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
00032  *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
00033  *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
00034  *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
00035  *
00036  */
00037 
00038 namespace Gecode { namespace Scheduling {
00039 
00040   forceinline int 
00041   plus(int x, int y) {
00042     assert(y != -Int::Limits::infinity);
00043     return (x == -Int::Limits::infinity) ? x : x+y;
00044   }
00045 
00046   forceinline double 
00047   plus(double x, double y) {
00048     assert(y != -Int::Limits::double_infinity);
00049     return (x == -Int::Limits::double_infinity) ? x : x+y;
00050   }
00051 
00052   forceinline double 
00053   div(double x, double y) {
00054     assert(y != -Int::Limits::double_infinity);
00055     return (x == -Int::Limits::double_infinity) ? x : x / y;
00056   }
00057 
00058   template<class TaskView, class Node>
00059   forceinline int 
00060   TaskTree<TaskView,Node>::n_inner(void) const {
00061     return tasks.size()-1;
00062   }
00063   template<class TaskView, class Node>
00064   forceinline int 
00065   TaskTree<TaskView,Node>::n_nodes(void) const {
00066     return 2*tasks.size() - 1;
00067   }
00068 
00069   template<class TaskView, class Node>
00070   forceinline bool 
00071   TaskTree<TaskView,Node>::n_root(int i) {
00072     return i == 0;
00073   }
00074   template<class TaskView, class Node>
00075   forceinline bool 
00076   TaskTree<TaskView,Node>::n_leaf(int i) const {
00077     return i >= n_inner();
00078   }
00079   template<class TaskView, class Node>
00080   forceinline int 
00081   TaskTree<TaskView,Node>::n_left(int i) {
00082     return 2*(i+1) - 1;
00083   }
00084   template<class TaskView, class Node>
00085   forceinline bool
00086   TaskTree<TaskView,Node>::left(int i) {
00087     assert(!n_root(i));
00088     // A left node has an odd number
00089     return (i & 1) != 0;
00090   }
00091   template<class TaskView, class Node>
00092   forceinline int
00093   TaskTree<TaskView,Node>::n_right(int i) {
00094     return 2*(i+1);
00095   }
00096   template<class TaskView, class Node>
00097   forceinline bool
00098   TaskTree<TaskView,Node>::right(int i) {
00099     assert(!n_root(i));
00100     // A left node has an even number
00101     return (i & 1) == 0;
00102   }
00103   template<class TaskView, class Node>
00104   forceinline int
00105   TaskTree<TaskView,Node>::n_parent(int i) {
00106     return (i+1)/2 - 1;
00107   }
00108 
00109   template<class TaskView, class Node>
00110   forceinline Node&
00111   TaskTree<TaskView,Node>::leaf(int i) {
00112     return node[_leaf[i]];
00113   }
00114 
00115   template<class TaskView, class Node>
00116   forceinline const Node&
00117   TaskTree<TaskView,Node>::root(void) const {
00118     return node[0];
00119   }
00120 
00121   template<class TaskView, class Node>
00122   forceinline void
00123   TaskTree<TaskView,Node>::init(void) {
00124     for (int i=n_inner(); i--; )
00125       node[i].init(node[n_left(i)],node[n_right(i)]);
00126   }
00127 
00128   template<class TaskView, class Node>
00129   forceinline void
00130   TaskTree<TaskView,Node>::update(int i, bool l) {
00131     if (l)
00132       i = _leaf[i];
00133     assert(!n_root(i));
00134     do {
00135       i = n_parent(i);
00136       node[i].update(node[n_left(i)],node[n_right(i)]);
00137     } while (!n_root(i));
00138   }
00139 
00140   template<class TaskView, class Node>
00141   forceinline
00142   TaskTree<TaskView,Node>::TaskTree(Region& r, 
00143                                     const TaskViewArray<TaskView>& t)
00144     : tasks(t), 
00145       node(r.alloc<Node>(n_nodes())),
00146       _leaf(r.alloc<int>(tasks.size())) {
00147     // Compute a sorting map to order by non decreasing est
00148     int* map = r.alloc<int>(tasks.size());
00149     sort<TaskView,STO_EST,true>(map, tasks);
00150     // Compute inverse of sorting map
00151     for (int i=tasks.size(); i--; )
00152       _leaf[map[i]] = i;
00153     r.free<int>(map,tasks.size());
00154     // Compute index of first leaf in tree: the next larger power of two
00155     int fst = 1;
00156     while (fst < tasks.size())
00157       fst <<= 1;
00158     fst--;
00159     // Remap task indices to leaf indices
00160     for (int i=tasks.size(); i--; )
00161       if (_leaf[i] + fst >= n_nodes())
00162         _leaf[i] += fst - tasks.size();
00163       else
00164         _leaf[i] += fst;
00165   }
00166 
00167   template<class TaskView, class Node> template<class Node2>
00168   forceinline
00169   TaskTree<TaskView,Node>::TaskTree(Region& r, 
00170                                     const TaskTree<TaskView,Node2>& t)
00171     : tasks(t.tasks), 
00172       node(r.alloc<Node>(n_nodes())),
00173       _leaf(r.alloc<int>(tasks.size())) {
00174     for (int i=tasks.size(); i--; )
00175       _leaf[i] = t._leaf[i];
00176   }
00177 
00178 }}
00179 
00180 // STATISTICS: scheduling-prop