union.icc

00001 /*
00002  *  Main authors:
00003  *     Guido Tack <tack@gecode.org>
00004  *     Christian Schulte <schulte@gecode.org>
00005  *
00006  *  Contributing authors:
00007  *     Gabor Szokoli <szokoli@gecode.org>
00008  *
00009  *  Copyright:
00010  *     Guido Tack, 2004
00011  *     Christian Schulte, 2004
00012  *     Gabor Szokoli, 2004
00013  *
00014  *  Last modified:
00015  *     $Date: 2006-08-25 17:31:32 +0200 (Fri, 25 Aug 2006) $ by $Author: tack $
00016  *     $Revision: 3573 $
00017  *
00018  *  This file is part of Gecode, the generic constraint
00019  *  development environment:
00020  *     http://www.gecode.org
00021  *
00022  *  See the file "LICENSE" for information on usage and
00023  *  redistribution of this file, and for a
00024  *     DISCLAIMER OF ALL WARRANTIES.
00025  *
00026  */
00027 
00028 namespace Gecode { namespace Set { namespace RelOp {
00029 
00030   /*
00031    * "Ternary union" propagator
00032    *
00033    */
00034 
00035   template <class View0, class View1, class View2>
00036   forceinline
00037   Union<View0,View1,View2>::Union(Space* home, View0 y0,View1 y1,View2 y2)
00038     : InhomTernaryPropagator<View0,PC_SET_ANY,View1,PC_SET_ANY,
00039                              View2,PC_SET_ANY>(home,y0,y1,y2) {}
00040 
00041   template <class View0, class View1, class View2>
00042   forceinline
00043   Union<View0,View1,View2>::Union(Space* home, bool share,
00044                                Union<View0,View1,View2>& p)
00045     : InhomTernaryPropagator<View0,PC_SET_ANY,View1,PC_SET_ANY,
00046                              View2,PC_SET_ANY>(home,share,p) {}
00047 
00048   template <class View0, class View1, class View2>
00049   ExecStatus Union<View0,View1,View2>::post(Space* home, View0 x0,
00050                                          View1 x1, View2 x2) {
00051     (void) new (home) Union<View0,View1,View2>(home,x0,x1,x2);
00052     return ES_OK;
00053   }
00054 
00055   template <class View0, class View1, class View2>
00056   Actor*
00057   Union<View0,View1,View2>::copy(Space* home, bool share) {
00058     return new (home) Union(home,share,*this);
00059   }
00060 
00061 
00062   template <class View0, class View1, class View2>
00063   ExecStatus
00064   Union<View0,View1,View2>::propagate(Space* home) {
00065     // This propagator implements the constraint
00066     // x2 = x0 u x1
00067 
00068     bool x0ass = x0.assigned();
00069     bool x1ass = x1.assigned();
00070     bool x2ass = x2.assigned();
00071 
00072     ModEvent me0 = View0::pme(this);
00073     ModEvent me1 = View1::pme(this);
00074     ModEvent me2 = View2::pme(this);
00075 
00076     bool x0ubmod = false;
00077     bool x1ubmod = false;
00078     bool modified = false;
00079 
00080     do {
00081 
00082       modified = false;
00083       do {
00084         // 4) lub(x2) <= lub(x0) u lub(x1)
00085         {
00086           LubRanges<View0> x0ub(x0);
00087           LubRanges<View1> x1ub(x1);
00088           Iter::Ranges::Union<LubRanges<View0>, LubRanges<View1> > u2(x0ub,x1ub);
00089           GECODE_ME_CHECK_MODIFIED(modified, x2.intersectI(home,u2) );
00090         }
00091 
00092         if (modified || Rel::testSetEventUB(me2) )
00093           {
00094             modified = false;
00095             // 5) x0 <= x2
00096             LubRanges<View2> x2ub1(x2);
00097             GECODE_ME_CHECK_MODIFIED(modified, x0.intersectI(home,x2ub1) );
00098             x0ubmod |= modified;
00099 
00100             // 6) x1 <= x2
00101             bool modified2=false;
00102             LubRanges<View2> x2ub2(x2);
00103             GECODE_ME_CHECK_MODIFIED(modified2, x1.intersectI(home,x2ub2) );
00104             x1ubmod |= modified2;
00105             modified |= modified2;
00106           }
00107 
00108       } while (modified);
00109 
00110       modified = false;
00111       do {
00112         bool modifiedOld = modified;
00113         modified = false;
00114 
00115         if (Rel::testSetEventLB(me2) || Rel::testSetEventUB(me0)
00116             || x0ubmod || modifiedOld)
00117           {
00118             // 1) glb(x0) \ lub(x1) <= glb(x2)
00119             GlbRanges<View2> x2lb(x2);
00120             LubRanges<View0> x0ub(x0);
00121             Iter::Ranges::Diff<GlbRanges<View2>, LubRanges<View0> >
00122               diff(x2lb, x0ub);
00123             GECODE_ME_CHECK_MODIFIED(modified, x1.includeI(home,diff) );
00124           }
00125 
00126         if (Rel::testSetEventLB(me2) || Rel::testSetEventUB(me1)
00127             || x1ubmod || modifiedOld)
00128           {
00129             // 2) glb(x0) \ lub(x2) <= glb(x1)
00130             GlbRanges<View2> x2lb(x2);
00131             LubRanges<View1> x1ub(x1);
00132             Iter::Ranges::Diff<GlbRanges<View2>, LubRanges<View1> >
00133               diff(x2lb, x1ub);
00134             GECODE_ME_CHECK_MODIFIED(modified, x0.includeI(home,diff) );
00135           }
00136 
00137         if (Rel::testSetEventLB(me0,me1) || modified)
00138           {
00139             //      modified = false;
00140             // 3) glb(x1) u glb(x2) <= glb(x0)
00141             GlbRanges<View0> x0lb(x0);
00142             GlbRanges<View1> x1lb(x1);
00143             Iter::Ranges::Union<GlbRanges<View0>, GlbRanges<View1> >
00144               u1(x0lb,x1lb);
00145             GECODE_ME_CHECK_MODIFIED(modified, x2.includeI(home,u1) );
00146           }
00147 
00148       } while(modified);
00149 
00150       modified = false;
00151       {
00152         // cardinality
00153         ExecStatus ret = unionCard(home,modified, x0, x1, x2);
00154         GECODE_ES_CHECK(ret);
00155       }
00156 
00157       if (x2.cardMax() == 0) {
00158         GECODE_ME_CHECK( x0.exclude(home,Limits::Set::int_min,
00159                                     Limits::Set::int_max) );
00160         GECODE_ME_CHECK( x1.exclude(home,Limits::Set::int_min,
00161                                     Limits::Set::int_max) );
00162         return ES_SUBSUMED;
00163       }
00164 
00165       if (x0.cardMax() == 0) {
00166         GECODE_ES_CHECK( (Rel::Eq<View2,View1>::post(home,x2,x1)) );
00167         return ES_SUBSUMED;
00168       }
00169 
00170       if (x1.cardMax() == 0) {
00171         GECODE_ES_CHECK( (Rel::Eq<View2,View0>::post(home,x2,x0)) );
00172         return ES_SUBSUMED;
00173       }
00174 
00175     } while(modified);
00176 
00177     if (shared(x0,x1,x2)) {
00178       return (x0ass && x1ass && x2ass) ? ES_SUBSUMED : ES_NOFIX;
00179     } else {
00180       if (x0ass && x1ass && x2ass)
00181         return ES_SUBSUMED;
00182       if (x0ass != x0.assigned() ||
00183           x1ass != x1.assigned() ||
00184           x2ass != x2.assigned()) {
00185         return ES_NOFIX;
00186       } else {
00187         return ES_FIX;
00188       }
00189     }
00190   }
00191 
00192 
00193   /*
00194    * "Nary union" propagator
00195    *
00196    */
00197 
00198   template <class View0, class View1>
00199   forceinline
00200   UnionN<View0,View1>::UnionN(Space* home, ViewArray<View0>& x, View1 y)
00201     : InhomNaryOnePropagator<View0,PC_SET_ANY,View1,PC_SET_ANY>(home,x,y) {
00202     shared = x.shared() || viewarrayshared(x,y);
00203   }
00204 
00205   template <class View0, class View1>
00206   forceinline
00207   UnionN<View0,View1>::UnionN(Space* home, bool share, UnionN& p)
00208     : InhomNaryOnePropagator<View0,PC_SET_ANY,View1,PC_SET_ANY>(home,share,p),
00209       shared(p.shared) {
00210     unionOfDets.update(home,p.unionOfDets);
00211   }
00212 
00213   template <class View0, class View1>
00214   Actor*
00215   UnionN<View0,View1>::copy(Space* home, bool share) {
00216     return new (home) UnionN<View0,View1>(home,share,*this);
00217   }
00218 
00219   template <class View0, class View1>
00220   ExecStatus UnionN<View0,View1>::post(Space* home,
00221                                       ViewArray<View0>& x, View1 y) {
00222     switch (x.size()) {
00223     case 0:
00224       GECODE_ME_CHECK(y.cardMax(home, 0));
00225       return ES_OK;
00226     case 1:
00227       return Rel::Eq<View0,View1>::post(home, x[0], y);
00228     case 2:
00229       return Union<View0,View0,View1>::post(home, x[0], x[1], y);
00230     default:
00231       (void) new (home) UnionN<View0,View1>(home,x,y);
00232       return ES_OK;
00233     }
00234   }
00235 
00236   template <class View0, class View1>
00237   PropCost UnionN<View0,View1>::cost(void) const {
00238     return PC_QUADRATIC_LO;
00239   }
00240 
00241   template <class View0, class View1>
00242   ExecStatus
00243   UnionN<View0,View1>::propagate(Space* home) {
00244     ModEvent me0 = View0::pme(this);
00245     ModEvent me1 = View1::pme(this);
00246     bool ubevent = Rel::testSetEventUB(me0, me1);
00247     bool lbevent = Rel::testSetEventLB(me0, me1);
00248     bool anybevent = Rel::testSetEventAnyB(me0, me1);
00249     bool cardevent = Rel::testSetEventCard(me0, me1);
00250 
00251     bool modified = false;
00252     bool oldModified = false;
00253 
00254     do {
00255       oldModified = modified;
00256       modified = false;
00257       if (modified || oldModified || ubevent)
00258         GECODE_ME_CHECK(unionNXiUB(home, modified, x, y,unionOfDets));
00259       if (modified || oldModified || ubevent)
00260         GECODE_ME_CHECK(partitionNYUB(home, modified, x, y,unionOfDets));
00261       if (modified || oldModified || anybevent)
00262         GECODE_ME_CHECK(partitionNXiLB(home, modified, x, y,unionOfDets));
00263       if (modified || oldModified || lbevent)
00264         GECODE_ME_CHECK(partitionNYLB(home, modified, x, y,unionOfDets));
00265       if (modified || oldModified || cardevent || ubevent)
00266         GECODE_ME_CHECK(unionNCard(home, modified, x, y, unionOfDets));
00267     } while (modified);
00268 
00269     for(int i=0;i<x.size();i++){
00270       //Do not reverse! Eats away the end of the array!
00271       while (i<x.size() && x[i].assigned()) {
00272         GlbRanges<View0> det(x[i]);
00273         unionOfDets.includeI(home,det);
00274         x.move_lst(i);
00275       }
00276     }
00277     // When we run out of variables, make a final check and disolve:
00278     if (x.size()==0) {
00279       BndSetRanges all1(unionOfDets);
00280       GECODE_ME_CHECK( y.intersectI(home,all1) );
00281       BndSetRanges all2(unionOfDets);
00282       GECODE_ME_CHECK( y.includeI(home,all2) );
00283       unionOfDets.dispose(home);
00284       return ES_SUBSUMED;
00285     }
00286 
00287     return shared ? ES_NOFIX : ES_FIX;
00288   }
00289 
00290 }}}
00291 
00292 // STATISTICS: set-prop