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opt-prop.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: 2010-07-15 12:52:54 +0200 (Thu, 15 Jul 2010) $ by $Author: tack $
00011  *     $Revision: 11200 $
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
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00022  *  permit persons to whom the Software is furnished to do so, subject to
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00025  *  The above copyright notice and this permission notice shall be
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00028  *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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00036  */
00037 
00038 #include <algorithm>
00039 
00040 namespace Gecode { namespace Scheduling { namespace Cumulative {
00041   
00042   template<class OptTask>
00043   forceinline
00044   OptProp<OptTask>::OptProp(Home home, int c0, TaskArray<OptTask>& t)
00045     : TaskProp<OptTask,Int::PC_INT_DOM>(home,t), c(c0) {}
00046 
00047   template<class OptTask>
00048   forceinline
00049   OptProp<OptTask>::OptProp(Space& home, bool shared, OptProp<OptTask>& p) 
00050     : TaskProp<OptTask,Int::PC_INT_DOM>(home,shared,p), c(p.c) {}
00051 
00052   template<class OptTask>
00053   forceinline ExecStatus 
00054   OptProp<OptTask>::post(Home home, int c, TaskArray<OptTask>& t) {
00055     // Check for overload by single task and remove excluded tasks
00056     int n=t.size(), m=0;
00057     for (int i=n; i--; ) {
00058       if (t[i].c() > c) 
00059         GECODE_ME_CHECK(t[i].excluded(home));
00060       if (t[i].excluded())
00061         t[i]=t[--n];
00062       else if (t[i].mandatory())
00063         m++;
00064     }
00065     t.size(n);
00066     if (t.size() < 2)
00067       return ES_OK;
00068     if (m == t.size()) {
00069       TaskArray<typename TaskTraits<OptTask>::ManTask> mt(home,m);
00070       for (int i=m; i--; )
00071         mt[i].init(t[i]);
00072       return ManProp<typename TaskTraits<OptTask>::ManTask>::post(home,c,mt);
00073     }
00074     (void) new (home) OptProp<OptTask>(home,c,t);
00075     return ES_OK;
00076   }
00077 
00078   template<class OptTask>
00079   Actor* 
00080   OptProp<OptTask>::copy(Space& home, bool share) {
00081     return new (home) OptProp<OptTask>(home,share,*this);
00082   }
00083 
00084   template<class OptTask>  
00085   forceinline size_t 
00086   OptProp<OptTask>::dispose(Space& home) {
00087     (void) TaskProp<OptTask,Int::PC_INT_DOM>::dispose(home);
00088     return sizeof(*this);
00089   }
00090 
00091   template<class OptTask>
00092   ExecStatus 
00093   OptProp<OptTask>::propagate(Space& home, const ModEventDelta& med) {
00094     // Did one of the Boolean views change?
00095     if (Int::BoolView::me(med) == Int::ME_BOOL_VAL)
00096       GECODE_ES_CHECK((purge<OptTask,Int::PC_INT_DOM>(home,*this,t)));
00097     // Only bounds changes?
00098     if (Int::IntView::me(med) != Int::ME_INT_DOM)
00099       GECODE_ES_CHECK(overload(home,c,t));
00100 
00101     GECODE_ES_CHECK(basic(home,*this,c,t));
00102 
00103     // Partition into mandatory and optional activities
00104     int n = t.size();
00105     int i=0, j=n-1;
00106     while (true) {
00107       while ((i < n) && t[i].mandatory()) i++;
00108       while ((j >= 0) && !t[j].mandatory()) j--;
00109       if (i >= j) break;
00110       std::swap(t[i],t[j]);
00111     }
00112 
00113     if (i > 1) {
00114       // Truncate array to only contain mandatory tasks
00115       t.size(i);
00116       GECODE_ES_CHECK(edgefinding(home,c,t));
00117       // Restore to also include optional tasks
00118       t.size(n);
00119     }
00120 
00121     return ES_NOFIX;
00122   }
00123 
00124 }}}
00125 
00126 // STATISTICS: scheduling-prop