101 lines
2.9 KiB
C++
101 lines
2.9 KiB
C++
/* -*- mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*- */
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/*
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* Main authors:
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* Christian Schulte <schulte@gecode.org>
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*
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* Copyright:
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* Christian Schulte, 2011
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*
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* This file is part of Gecode, the generic constraint
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* development environment:
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* http://www.gecode.org
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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*/
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#include <gecode/int/bool.hh>
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namespace Gecode { namespace Int { namespace Bool {
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/*
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* N-ary Boolean equivalence propagator
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*
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*/
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PropCost
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NaryEqv::cost(const Space&, const ModEventDelta&) const {
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return PropCost::binary(PropCost::LO);
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}
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Actor*
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NaryEqv::copy(Space& home) {
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return new (home) NaryEqv(home,*this);
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}
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ExecStatus
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NaryEqv::post(Home home, ViewArray<BoolView>& x, int pm2) {
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int n = x.size();
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for (int i=n; i--; )
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if (x[i].assigned()) {
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pm2 ^= x[i].val();
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x[i] = x[--n];
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}
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if (n == 0)
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return (pm2 == 1) ? ES_OK : ES_FAILED;
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if (n == 1) {
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GECODE_ME_CHECK(x[0].eq(home,1^pm2));
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return ES_OK;
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}
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if (n == 2) {
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if (pm2 == 1) {
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return Bool::Eq<BoolView,BoolView>::post(home,x[0],x[1]);
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} else {
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NegBoolView nx(x[1]);
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return Bool::Eq<BoolView,NegBoolView>::post(home,x[0],nx);
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}
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}
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x.size(n);
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(void) new (home) NaryEqv(home,x,pm2);
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return ES_OK;
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}
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ExecStatus
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NaryEqv::propagate(Space& home, const ModEventDelta&) {
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resubscribe(home,x0);
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resubscribe(home,x1);
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if (x.size() == 0) {
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if (x0.assigned() && x1.assigned()) {
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return (pm2 == 1) ? home.ES_SUBSUMED(*this) : ES_FAILED;
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} else if (x0.assigned()) {
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GECODE_ME_CHECK(x1.eq(home,1^pm2));
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return home.ES_SUBSUMED(*this);
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} else if (x1.assigned()) {
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GECODE_ME_CHECK(x0.eq(home,1^pm2));
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return home.ES_SUBSUMED(*this);
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}
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}
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return ES_FIX;
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}
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}}}
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// STATISTICS: int-prop
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