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namespace Gecode { namespace Set { namespace Element {
template<class View, class View0, class View1> forceinline ElementUnion<View,View0,View1>:: ElementUnion(Home home, IdxViewArray& iv0, View0 y0, View1 y1) : Propagator(home), iv(iv0), x0(y0), x1(y1) { home.notice(*this,AP_DISPOSE); x0.subscribe(home,*this, PC_SET_ANY); x1.subscribe(home,*this, PC_SET_ANY); iv.subscribe(home,*this, PC_SET_ANY); }
template<class View, class View0, class View1> forceinline ElementUnion<View,View0,View1>:: ElementUnion(Space& home, ElementUnion<View,View0,View1>& p) : Propagator(home,p) { x0.update(home,p.x0); x1.update(home,p.x1); iv.update(home,p.iv); }
template<class View, class View0, class View1> PropCost ElementUnion<View,View0,View1>::cost(const Space&, const ModEventDelta&) const { return PropCost::linear(PropCost::HI, iv.size()+2); }
template<class View, class View0, class View1> void ElementUnion<View,View0,View1>::reschedule(Space& home) { x0.reschedule(home,*this, PC_SET_ANY); x1.reschedule(home,*this, PC_SET_ANY); iv.reschedule(home,*this, PC_SET_ANY); }
template<class View, class View0, class View1> forceinline size_t ElementUnion<View,View0,View1>::dispose(Space& home) { home.ignore(*this,AP_DISPOSE); if (!home.failed()) { x0.cancel(home,*this,PC_SET_ANY); x1.cancel(home,*this,PC_SET_ANY); iv.cancel(home,*this,PC_SET_ANY); } (void) Propagator::dispose(home); return sizeof(*this); }
template<class View, class View0, class View1> ExecStatus ElementUnion<View,View0,View1>:: post(Home home, IdxViewArray& xs, View0 x0, View1 x1) { int n = xs.size();
// x0 \subseteq {1,...,n} Iter::Ranges::Singleton s(0, n-1); GECODE_ME_CHECK(x0.intersectI(home,s)); (void) new (home) ElementUnion<View,View0,View1>(home,xs,x0,x1); return ES_OK; }
template<class View, class View0, class View1> Actor* ElementUnion<View,View0,View1>::copy(Space& home) { return new (home) ElementUnion<View,View0,View1>(home,*this); }
template<class View, class View0, class View1> ExecStatus ElementUnion<View,View0,View1>::propagate(Space& home, const ModEventDelta&) { Region r; int n = iv.size();
bool loopVar; do { loopVar = false;
// Cache the upper bound iterator, as we have to // modify the upper bound while iterating LubRanges<View0> x0ub(x0); Iter::Ranges::Cache x0ubc(r,x0ub); Iter::Ranges::ToValues<Iter::Ranges::Cache> vx0ub(x0ubc);
GlbRanges<View0> x0lb(x0); Iter::Ranges::Cache x0lbc(r,x0lb); Iter::Ranges::ToValues<Iter::Ranges::Cache> vx0(x0lbc);
// In the first iteration, compute in before[i] the union // of all the upper bounds of the x_i. At the same time, // exclude inconsistent x_i from x0 and remove them from // the list, cancel their dependencies.
GLBndSet sofarBefore(home); LUBndSet selectedInter(home, IntSet (Limits::min, Limits::max)); GLBndSet* before = static_cast<GLBndSet*>(r.ralloc(sizeof(GLBndSet)*n));
int j = 0; int i = 0;
unsigned int maxCard = 0; unsigned int minCard = Limits::card;
while ( vx0ub() ) {
// Remove vars at indices not in the upper bound if (iv[i].idx < vx0ub.val()) { iv[i].view.cancel(home,*this, PC_SET_ANY); ++i; continue; } assert(iv[i].idx == vx0ub.val()); iv[j] = iv[i];
View candidate = iv[j].view; int candidateInd = iv[j].idx;
// inter = glb(candidate) & complement(lub(x1)) GlbRanges<View> candlb(candidate); LubRanges<View1> x1ub(x1); Iter::Ranges::Diff<GlbRanges<View>, LubRanges<View1> > diff(candlb, x1ub);
bool selectSingleInconsistent = false; if (x0.cardMax() <= 1) { GlbRanges<View1> x1lb(x1); LubRanges<View> candub(candidate); Iter::Ranges::Diff<GlbRanges<View1>, LubRanges<View> > diff2(x1lb, candub); selectSingleInconsistent = diff2() || candidate.cardMax() < x1.cardMin(); }
// exclude inconsistent x_i // an x_i is inconsistent if // * at most one x_i can be selected and there are // elements in x_0 that can't be in x_i // (selectSingleInconsistent) // * its min cardinality is greater than maxCard of x1 // * inter is not empty (there are elements in x_i // that can't be in x_0) if (selectSingleInconsistent || candidate.cardMin() > x1.cardMax() || diff()) { ModEvent me = (x0.exclude(home,candidateInd)); loopVar |= me_modified(me); GECODE_ME_CHECK(me);
iv[j].view.cancel(home,*this, PC_SET_ANY); ++i; ++vx0ub; continue; } else { // if x_i is consistent, check whether we know // that its index is in x0 if (vx0() && vx0.val()==candidateInd) { // x1 >= candidate, candidate <= x1 GlbRanges<View> candlb(candidate); ModEvent me = x1.includeI(home,candlb); loopVar |= me_modified(me); GECODE_ME_CHECK(me);
LubRanges<View1> x1ub(x1); me = candidate.intersectI(home,x1ub); loopVar |= me_modified(me); GECODE_ME_CHECK(me); ++vx0; } new (&before[j]) GLBndSet(home); before[j].update(home,sofarBefore); LubRanges<View> cub(candidate); sofarBefore.includeI(home,cub); GlbRanges<View> clb(candidate); selectedInter.intersectI(home,clb); maxCard = std::max(maxCard, candidate.cardMax()); minCard = std::min(minCard, candidate.cardMin()); }
++vx0ub; ++i; ++j; }
// cancel the variables with index greater than // max of lub(x0) for (int k=i; k<n; k++) { iv[k].view.cancel(home,*this, PC_SET_ANY); } n = j; iv.size(n);
if (x0.cardMax()==0) { // Selector is empty, hence the result must be empty { GECODE_ME_CHECK(x1.cardMax(home,0)); } for (int i=n; i--;) before[i].dispose(home); return home.ES_SUBSUMED(*this); }
if (x0.cardMin() > 0) { // Selector is not empty, hence the intersection of the // possibly selected lower bounds is contained in x1 BndSetRanges si(selectedInter); ModEvent me = x1.includeI(home, si); loopVar |= me_modified(me); GECODE_ME_CHECK(me); me = x1.cardMin(home, minCard); loopVar |= me_modified(me); GECODE_ME_CHECK(me); } selectedInter.dispose(home);
if (x0.cardMax() <= 1) { ModEvent me = x1.cardMax(home, maxCard); loopVar |= me_modified(me); GECODE_ME_CHECK(me); }
{ // x1 <= sofarBefore BndSetRanges sfB(sofarBefore); ModEvent me = x1.intersectI(home,sfB); loopVar |= me_modified(me); GECODE_ME_CHECK(me); }
sofarBefore.dispose(home);
GLBndSet sofarAfter(home);
// In the second iteration, this time backwards, compute // sofarAfter as the union of all lub(x_j) with j>i for (int i=n; i--;) { // TODO: check for size of universe here? // if (sofarAfter.size() == 0) break;
// extra = inter(before[i], sofarAfter) - lub(x1) BndSetRanges b(before[i]); BndSetRanges s(sofarAfter); GlbRanges<View1> x1lb(x1); Iter::Ranges::Union<BndSetRanges, BndSetRanges> inter(b,s); Iter::Ranges::Diff<GlbRanges<View1>, Iter::Ranges::Union<BndSetRanges,BndSetRanges> > diff(x1lb, inter); if (diff()) { ModEvent me = (x0.include(home,iv[i].idx)); loopVar |= me_modified(me); GECODE_ME_CHECK(me);
// candidate != extra me = iv[i].view.includeI(home,diff); loopVar |= me_modified(me); GECODE_ME_CHECK(me); }
LubRanges<View> iviub(iv[i].view); sofarAfter.includeI(home,iviub); before[i].dispose(home); } sofarAfter.dispose(home);
} while (loopVar);
// Test whether we determined x0 without determining x1 if (x0.assigned() && !x1.assigned()) { int ubsize = static_cast<int>(x0.lubSize()); if (ubsize > 2) { assert(ubsize==n); ViewArray<View> is(home,ubsize); for (int i=n; i--;) is[i]=iv[i].view; GECODE_REWRITE(*this,(RelOp::UnionN<View, View1> ::post(home(*this),is,x1))); } else if (ubsize == 2) { assert(n==2); View a = iv[0].view; View b = iv[1].view; GECODE_REWRITE(*this,(RelOp::Union<View,View,View1> ::post(home(*this),a,b,x1))); } else if (ubsize == 1) { assert(n==1); GECODE_REWRITE(*this, (Rel::Eq<View1,View>::post(home(*this),x1,iv[0].view))); } else { GECODE_ME_CHECK(x1.cardMax(home, 0)); return home.ES_SUBSUMED(*this); } }
for (int i=iv.size(); i--;) if (!iv[i].view.assigned()) return ES_FIX; if (!x1.assigned() || !x0.assigned()) return ES_FIX; return home.ES_SUBSUMED(*this); }
}}}
// STATISTICS: set-prop