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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- *//* * Main authors: * Patrick Pekczynski <pekczynski@ps.uni-sb.de> * * Contributing authors: * Christian Schulte <schulte@gecode.org> * Guido Tack <tack@gecode.org> * * Copyright: * Patrick Pekczynski, 2004 * Christian Schulte, 2009 * Guido Tack, 2009 * * This file is part of Gecode, the generic constraint * development environment: * http://www.gecode.org * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * "Software"), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. * */
namespace Gecode { namespace Int { namespace GCC {
/* * Analogously to "gcc/bnd.hpp" we split the algorithm * in two parts: * 1) the UBC (Upper Bound Constraint) stating that there are * at most k[i].max() occurences of the value v_i * 2) the LBC (Lower Bound Constraint) stating that there are * at least k[i].min() occurences of the value v_i * * The algorithm proceeds in 5 STEPS: * * STEP 1: * Build the bipartite value-graph G=(<X,D>,E), * with X = all variable nodes (each variable forms a node) * D = all value nodes (union over all domains of the variables) * and (x_i,v) is an edge in G iff value v is in the domain D_i of x_i * * STEP 2: Compute a matching in the value graph. * STEP 3: Compute all even alternating paths from unmatched nodes * STEP 4: Compute strongly connected components in the merged graph * STEP 5: Update the Domains according to the computed edges * */
template<class Card> inline Dom<Card>::Dom(Home home, ViewArray<IntView>& x0, ViewArray<Card>& k0, bool cf) : Propagator(home), x(x0), y(home, x0), k(k0), vvg(nullptr), card_fixed(cf){ // y is used for bounds propagation since prop_bnd needs all variables // values within the domain bounds x.subscribe(home, *this, PC_INT_DOM); k.subscribe(home, *this, PC_INT_DOM); }
template<class Card> forceinline Dom<Card>::Dom(Space& home, Dom<Card>& p) : Propagator(home, p), vvg(nullptr), card_fixed(p.card_fixed) { x.update(home, p.x); y.update(home, p.y); k.update(home, p.k); }
template<class Card> forceinline size_t Dom<Card>::dispose(Space& home) { x.cancel(home,*this, PC_INT_DOM); k.cancel(home,*this, PC_INT_DOM); (void) Propagator::dispose(home); return sizeof(*this); }
template<class Card> Actor* Dom<Card>::copy(Space& home) { return new (home) Dom<Card>(home, *this); }
template<class Card> PropCost Dom<Card>::cost(const Space&, const ModEventDelta&) const { return PropCost::cubic(PropCost::LO, x.size()); }
template<class Card> void Dom<Card>::reschedule(Space& home) { x.reschedule(home, *this, PC_INT_DOM); k.reschedule(home, *this, PC_INT_DOM); }
template<class Card> ExecStatus Dom<Card>::propagate(Space& home, const ModEventDelta&) { Region r;
int* count = r.alloc<int>(k.size()); for (int i = k.size(); i--; ) count[i] = 0;
// total number of assigned views int noa = 0; for (int i = y.size(); i--; ) if (y[i].assigned()) { noa++; int idx; if (!lookupValue(k,y[i].val(),idx)) return ES_FAILED; count[idx]++; if (Card::propagate && (k[idx].max() == 0)) return ES_FAILED; }
if (noa == y.size()) { // All views are assigned for (int i = k.size(); i--; ) { if ((k[i].min() > count[i]) || (count[i] > k[i].max())) return ES_FAILED; // the solution contains ci occurences of value k[i].card(); if (Card::propagate) GECODE_ME_CHECK(k[i].eq(home, count[i])); } return home.ES_SUBSUMED(*this); }
// before propagation performs inferences on cardinality variables: if (Card::propagate) { if (noa > 0) for (int i = k.size(); i--; ) if (!k[i].assigned()) { GECODE_ME_CHECK(k[i].lq(home, y.size() - (noa - count[i]))); GECODE_ME_CHECK(k[i].gq(home, count[i])); }
GECODE_ES_CHECK(prop_card<Card>(home,y,k)); if (!card_consistent<Card>(y,k)) return ES_FAILED; }
if (x.size() == 0) { for (int j = k.size(); j--; ) if ((k[j].min() > k[j].counter()) || (k[j].max() < k[j].counter())) return ES_FAILED; return home.ES_SUBSUMED(*this); } else if ((x.size() == 1) && (x[0].assigned())) { int idx; if (!lookupValue(k,x[0].val(),idx)) return ES_FAILED; GECODE_ME_CHECK(k[idx].inc()); for (int j = k.size(); j--; ) if ((k[j].min() > k[j].counter()) || (k[j].max() < k[j].counter())) return ES_FAILED; return home.ES_SUBSUMED(*this); }
if (vvg == nullptr) { int smin = 0; int smax = 0; for (int i=k.size(); i--; ) if (k[i].counter() > k[i].max() ) { return ES_FAILED; } else { smax += (k[i].max() - k[i].counter()); if (k[i].counter() < k[i].min()) smin += (k[i].min() - k[i].counter()); }
if ((x.size() < smin) || (smax < x.size())) return ES_FAILED;
vvg = new (home) VarValGraph<Card>(home, x, k, smin, smax); GECODE_ES_CHECK(vvg->min_require(home,x,k)); GECODE_ES_CHECK(vvg->template maximum_matching<UBC>()); if (!card_fixed) GECODE_ES_CHECK(vvg->template maximum_matching<LBC>()); } else { GECODE_ES_CHECK(vvg->sync(x,k)); }
vvg->template free_alternating_paths<UBC>(); vvg->template strongly_connected_components<UBC>();
GECODE_ES_CHECK(vvg->template narrow<UBC>(home,x,k));
if (!card_fixed) { if (Card::propagate) GECODE_ES_CHECK(vvg->sync(x,k));
vvg->template free_alternating_paths<LBC>(); vvg->template strongly_connected_components<LBC>();
GECODE_ES_CHECK(vvg->template narrow<LBC>(home,x,k)); }
{ bool card_assigned = true; if (Card::propagate) { GECODE_ES_CHECK(prop_card<Card>(home, y, k)); card_assigned = k.assigned(); }
if (card_assigned) { if (x.size() == 0) { for (int j=k.size(); j--; ) if ((k[j].min() > k[j].counter()) || (k[j].max() < k[j].counter())) return ES_FAILED; return home.ES_SUBSUMED(*this); } else if ((x.size() == 1) && x[0].assigned()) { int idx; if (!lookupValue(k,x[0].val(),idx)) return ES_FAILED; GECODE_ME_CHECK(k[idx].inc());
for (int j = k.size(); j--; ) if ((k[j].min() > k[j].counter()) || (k[j].max() < k[j].counter())) return ES_FAILED; return home.ES_SUBSUMED(*this); } } }
for (int i = k.size(); i--; ) count[i] = 0;
bool all_assigned = true; // total number of assigned views for (int i = y.size(); i--; ) if (y[i].assigned()) { int idx; if (!lookupValue(k,y[i].val(),idx)) return ES_FAILED; count[idx]++; if (Card::propagate && (k[idx].max() == 0)) return ES_FAILED; } else { all_assigned = false; }
if (Card::propagate) GECODE_ES_CHECK(prop_card<Card>(home, y, k));
if (all_assigned) { for (int i = k.size(); i--; ) { if ((k[i].min() > count[i]) || (count[i] > k[i].max())) return ES_FAILED; // the solution contains count[i] occurences of value k[i].card(); if (Card::propagate) GECODE_ME_CHECK(k[i].eq(home,count[i])); } return home.ES_SUBSUMED(*this); }
if (Card::propagate) { int ysmax = y.size(); for (int i=k.size(); i--; ) ysmax -= k[i].max(); int smax = 0; bool card_ass = true; for (int i = k.size(); i--; ) { GECODE_ME_CHECK(k[i].gq(home, ysmax + k[i].max())); smax += k[i].max(); GECODE_ME_CHECK(k[i].lq(home, y.size() + k[i].min())); if (!k[i].assigned()) card_ass = false; } if (card_ass && (smax != y.size())) return ES_FAILED; }
return Card::propagate ? ES_NOFIX : ES_FIX; }
template<class Card> inline ExecStatus Dom<Card>::post(Home home, ViewArray<IntView>& x, ViewArray<Card>& k) { GECODE_ES_CHECK((postSideConstraints<Card>(home,x,k)));
if (isDistinct<Card>(x,k)) return Distinct::Dom<IntView>::post(home,x);
bool cardfix = true; for (int i = k.size(); i--; ) if (!k[i].assigned()) { cardfix = false; break; }
(void) new (home) Dom<Card>(home,x,k,cardfix); return ES_OK; }
}}}
// STATISTICS: int-prop