gecode » scheduling » task
tree.hpp

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: 2009-10-05 14:07:04 +0200 (Mon, 05 Oct 2009) $ by $Author: schulte $
00011  *     $Revision: 9815 $
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   template<class TaskView, class Node>
00047   forceinline int 
00048   TaskTree<TaskView,Node>::n_inner(void) const {
00049     return tasks.size()-1;
00050   }
00051   template<class TaskView, class Node>
00052   forceinline int 
00053   TaskTree<TaskView,Node>::n_nodes(void) const {
00054     return 2*tasks.size() - 1;
00055   }
00056 
00057   template<class TaskView, class Node>
00058   forceinline bool 
00059   TaskTree<TaskView,Node>::n_root(int i) {
00060     return i == 0;
00061   }
00062   template<class TaskView, class Node>
00063   forceinline bool 
00064   TaskTree<TaskView,Node>::n_leaf(int i) const {
00065     return i > n_inner();
00066   }
00067   template<class TaskView, class Node>
00068   forceinline int 
00069   TaskTree<TaskView,Node>::n_left(int i) {
00070     return 2*(i+1) - 1;
00071   }
00072   template<class TaskView, class Node>
00073   forceinline int
00074   TaskTree<TaskView,Node>::n_right(int i) {
00075     return 2*(i+1);
00076   }
00077   template<class TaskView, class Node>
00078   forceinline int
00079   TaskTree<TaskView,Node>::n_parent(int i) {
00080     return (i+1)/2 - 1;
00081   }
00082 
00083   template<class TaskView, class Node>
00084   forceinline Node&
00085   TaskTree<TaskView,Node>::leaf(int i) {
00086     return node[_leaf[i]];
00087   }
00088 
00089   template<class TaskView, class Node>
00090   forceinline const Node&
00091   TaskTree<TaskView,Node>::root(void) const {
00092     return node[0];
00093   }
00094 
00095   template<class TaskView, class Node>
00096   forceinline void
00097   TaskTree<TaskView,Node>::init(void) {
00098     for (int i=n_inner(); i--; )
00099       node[i].init(node[n_left(i)],node[n_right(i)]);
00100   }
00101 
00102   template<class TaskView, class Node>
00103   forceinline void
00104   TaskTree<TaskView,Node>::update(int i, bool l) {
00105     if (l)
00106       i = _leaf[i];
00107     assert(!n_root(i));
00108     do {
00109       i = n_parent(i);
00110       node[i].update(node[n_left(i)],node[n_right(i)]);
00111     } while (!n_root(i));
00112   }
00113 
00114   template<class TaskView, class Node>
00115   forceinline
00116   TaskTree<TaskView,Node>::TaskTree(Region& r, 
00117                                     const TaskViewArray<TaskView>& t)
00118     : tasks(t), 
00119       node(r.alloc<Node>(n_nodes())),
00120       _leaf(r.alloc<int>(tasks.size())) {
00121     // Compute a sorting map to order by non decreasing est
00122     int* map = r.alloc<int>(tasks.size());
00123     sort<TaskView,STO_EST,true>(map, tasks);
00124     // Compute inverse of sorting map
00125     for (int i=tasks.size(); i--; )
00126       _leaf[map[i]] = i;
00127     r.free<int>(map,tasks.size());
00128     // Compute index of first leaf in tree: the next larger power of two
00129     int fst = 1;
00130     while (fst < tasks.size())
00131       fst <<= 1;
00132     fst--;
00133     // Remap task indices to leaf indices
00134     for (int i=tasks.size(); i--; )
00135       if (_leaf[i] + fst >= n_nodes())
00136         _leaf[i] += fst - tasks.size();
00137       else
00138         _leaf[i] += fst;
00139   }
00140 
00141 }}
00142 
00143 // STATISTICS: scheduling-prop