827 lines
25 KiB
C++
827 lines
25 KiB
C++
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/***************************************************************************************[SimpSolver.cc]
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Glucose -- Copyright (c) 2009-2014, Gilles Audemard, Laurent Simon
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CRIL - Univ. Artois, France
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LRI - Univ. Paris Sud, France (2009-2013)
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Labri - Univ. Bordeaux, France
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Syrup (Glucose Parallel) -- Copyright (c) 2013-2014, Gilles Audemard, Laurent Simon
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CRIL - Univ. Artois, France
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Labri - Univ. Bordeaux, France
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Glucose sources are based on MiniSat (see below MiniSat copyrights). Permissions and copyrights of
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Glucose (sources until 2013, Glucose 3.0, single core) are exactly the same as Minisat on which it
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is based on. (see below).
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Glucose-Syrup sources are based on another copyright. Permissions and copyrights for the parallel
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version of Glucose-Syrup (the "Software") are granted, free of charge, to deal with the Software
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without restriction, including the rights to use, copy, modify, merge, publish, distribute,
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sublicence, and/or sell copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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- The above and below copyrights notices and this permission notice shall be included in all
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copies or substantial portions of the Software;
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- The parallel version of Glucose (all files modified since Glucose 3.0 releases, 2013) cannot
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be used in any competitive event (sat competitions/evaluations) without the express permission of
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the authors (Gilles Audemard / Laurent Simon). This is also the case for any competitive event
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using Glucose Parallel as an embedded SAT engine (single core or not).
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--------------- Original Minisat Copyrights
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Copyright (c) 2003-2006, Niklas Een, Niklas Sorensson
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Copyright (c) 2007-2010, Niklas Sorensson
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Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
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associated documentation files (the "Software"), to deal in the Software without restriction,
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including without limitation the rights to use, copy, modify, merge, publish, distribute,
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sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
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furnished to do so, subject to the following conditions:
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The above copyright notice and this permission notice shall be included in all copies or
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substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
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NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT
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OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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**************************************************************************************************/
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#include "mtl/Sort.h"
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#include "simp/SimpSolver.h"
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#include "utils/System.h"
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using namespace Glucose;
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//=================================================================================================
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// Options:
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static const char* _cat = "SIMP";
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static BoolOption opt_use_asymm (_cat, "asymm", "Shrink clauses by asymmetric branching.", false);
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static BoolOption opt_use_rcheck (_cat, "rcheck", "Check if a clause is already implied. (costly)", false);
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static BoolOption opt_use_elim (_cat, "elim", "Perform variable elimination.", true);
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static IntOption opt_grow (_cat, "grow", "Allow a variable elimination step to grow by a number of clauses.", 0);
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static IntOption opt_clause_lim (_cat, "cl-lim", "Variables are not eliminated if it produces a resolvent with a length above this limit. -1 means no limit", 20, IntRange(-1, INT32_MAX));
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static IntOption opt_subsumption_lim (_cat, "sub-lim", "Do not check if subsumption against a clause larger than this. -1 means no limit.", 1000, IntRange(-1, INT32_MAX));
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static DoubleOption opt_simp_garbage_frac(_cat, "simp-gc-frac", "The fraction of wasted memory allowed before a garbage collection is triggered during simplification.", 0.5, DoubleRange(0, false, HUGE_VAL, false));
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//=================================================================================================
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// Constructor/Destructor:
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SimpSolver::SimpSolver() :
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Solver()
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, grow (opt_grow)
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, clause_lim (opt_clause_lim)
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, subsumption_lim (opt_subsumption_lim)
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, simp_garbage_frac (opt_simp_garbage_frac)
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, use_asymm (opt_use_asymm)
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, use_rcheck (opt_use_rcheck)
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, use_elim (opt_use_elim)
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, merges (0)
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, asymm_lits (0)
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, eliminated_vars (0)
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, elimorder (1)
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, use_simplification (true)
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, occurs (ClauseDeleted(ca))
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, elim_heap (ElimLt(n_occ))
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, bwdsub_assigns (0)
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, n_touched (0)
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{
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vec<Lit> dummy(1,lit_Undef);
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ca.extra_clause_field = true; // NOTE: must happen before allocating the dummy clause below.
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bwdsub_tmpunit = ca.alloc(dummy);
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remove_satisfied = false;
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}
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SimpSolver::~SimpSolver()
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{
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}
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SimpSolver::SimpSolver(const SimpSolver &s) : Solver(s)
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, grow (s.grow)
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, clause_lim (s.clause_lim)
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, subsumption_lim (s.subsumption_lim)
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, simp_garbage_frac (s.simp_garbage_frac)
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, use_asymm (s.use_asymm)
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, use_rcheck (s.use_rcheck)
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, use_elim (s.use_elim)
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, merges (s.merges)
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, asymm_lits (s.asymm_lits)
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, eliminated_vars (s.eliminated_vars)
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, elimorder (s.elimorder)
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, use_simplification (s.use_simplification)
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, occurs (ClauseDeleted(ca))
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, elim_heap (ElimLt(n_occ))
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, bwdsub_assigns (s.bwdsub_assigns)
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, n_touched (s.n_touched)
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{
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// TODO: Copy dummy... what is it???
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vec<Lit> dummy(1,lit_Undef);
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ca.extra_clause_field = true; // NOTE: must happen before allocating the dummy clause below.
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bwdsub_tmpunit = ca.alloc(dummy);
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remove_satisfied = false;
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//End TODO
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s.elimclauses.memCopyTo(elimclauses);
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s.touched.memCopyTo(touched);
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s.occurs.copyTo(occurs);
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s.n_occ.memCopyTo(n_occ);
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s.elim_heap.copyTo(elim_heap);
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s.subsumption_queue.copyTo(subsumption_queue);
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s.frozen.memCopyTo(frozen);
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s.eliminated.memCopyTo(eliminated);
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use_simplification = s.use_simplification;
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bwdsub_assigns = s.bwdsub_assigns;
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n_touched = s.n_touched;
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bwdsub_tmpunit = s.bwdsub_tmpunit;
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qhead = s.qhead;
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ok = s.ok;
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}
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Var SimpSolver::newVar(bool sign, bool dvar) {
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Var v = Solver::newVar(sign, dvar);
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frozen .push((char)false);
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eliminated.push((char)false);
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if (use_simplification){
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n_occ .push(0);
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n_occ .push(0);
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occurs .init(v);
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touched .push(0);
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elim_heap .insert(v);
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}
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return v; }
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lbool SimpSolver::solve_(bool do_simp, bool turn_off_simp)
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{
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vec<Var> extra_frozen;
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lbool result = l_True;
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do_simp &= use_simplification;
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if (do_simp){
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// Assumptions must be temporarily frozen to run variable elimination:
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for (int i = 0; i < assumptions.size(); i++){
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Var v = var(assumptions[i]);
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// If an assumption has been eliminated, remember it.
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assert(!isEliminated(v));
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if (!frozen[v]){
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// Freeze and store.
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setFrozen(v, true);
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extra_frozen.push(v);
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} }
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result = lbool(eliminate(turn_off_simp));
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}
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if (result == l_True)
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result = Solver::solve_();
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else if (verbosity >= 1)
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printf("===============================================================================\n");
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if (result == l_True)
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extendModel();
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if (do_simp)
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// Unfreeze the assumptions that were frozen:
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for (int i = 0; i < extra_frozen.size(); i++)
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setFrozen(extra_frozen[i], false);
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return result;
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}
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bool SimpSolver::addClause_(vec<Lit>& ps)
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{
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#ifndef NDEBUG
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for (int i = 0; i < ps.size(); i++)
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assert(!isEliminated(var(ps[i])));
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#endif
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int nclauses = clauses.size();
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if (use_rcheck && implied(ps))
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return true;
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if (!Solver::addClause_(ps))
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return false;
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if(!parsing && certifiedUNSAT) {
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for (int i = 0; i < ps.size(); i++)
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fprintf(certifiedOutput, "%i " , (var(ps[i]) + 1) * (-2 * sign(ps[i]) + 1) );
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fprintf(certifiedOutput, "0\n");
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}
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if (use_simplification && clauses.size() == nclauses + 1){
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CRef cr = clauses.last();
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const Clause& c = ca[cr];
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// NOTE: the clause is added to the queue immediately and then
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// again during 'gatherTouchedClauses()'. If nothing happens
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// in between, it will only be checked once. Otherwise, it may
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// be checked twice unnecessarily. This is an unfortunate
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// consequence of how backward subsumption is used to mimic
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// forward subsumption.
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subsumption_queue.insert(cr);
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for (int i = 0; i < c.size(); i++){
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occurs[var(c[i])].push(cr);
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n_occ[toInt(c[i])]++;
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touched[var(c[i])] = 1;
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n_touched++;
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if (elim_heap.inHeap(var(c[i])))
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elim_heap.increase(var(c[i]));
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}
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}
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return true;
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}
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void SimpSolver::removeClause(CRef cr,bool inPurgatory)
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{
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const Clause& c = ca[cr];
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if (use_simplification)
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for (int i = 0; i < c.size(); i++){
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n_occ[toInt(c[i])]--;
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updateElimHeap(var(c[i]));
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occurs.smudge(var(c[i]));
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}
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Solver::removeClause(cr,inPurgatory);
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}
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bool SimpSolver::strengthenClause(CRef cr, Lit l)
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{
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Clause& c = ca[cr];
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assert(decisionLevel() == 0);
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assert(use_simplification);
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// FIX: this is too inefficient but would be nice to have (properly implemented)
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// if (!find(subsumption_queue, &c))
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subsumption_queue.insert(cr);
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if (certifiedUNSAT) {
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for (int i = 0; i < c.size(); i++)
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if (c[i] != l) fprintf(certifiedOutput, "%i " , (var(c[i]) + 1) * (-2 * sign(c[i]) + 1) );
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fprintf(certifiedOutput, "0\n");
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}
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if (c.size() == 2){
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removeClause(cr);
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c.strengthen(l);
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}else{
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if (certifiedUNSAT) {
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fprintf(certifiedOutput, "d ");
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for (int i = 0; i < c.size(); i++)
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fprintf(certifiedOutput, "%i " , (var(c[i]) + 1) * (-2 * sign(c[i]) + 1) );
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fprintf(certifiedOutput, "0\n");
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}
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detachClause(cr, true);
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c.strengthen(l);
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attachClause(cr);
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remove(occurs[var(l)], cr);
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n_occ[toInt(l)]--;
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updateElimHeap(var(l));
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}
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return c.size() == 1 ? enqueue(c[0]) && propagate() == CRef_Undef : true;
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}
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// Returns FALSE if clause is always satisfied ('out_clause' should not be used).
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bool SimpSolver::merge(const Clause& _ps, const Clause& _qs, Var v, vec<Lit>& out_clause)
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{
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merges++;
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out_clause.clear();
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bool ps_smallest = _ps.size() < _qs.size();
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const Clause& ps = ps_smallest ? _qs : _ps;
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const Clause& qs = ps_smallest ? _ps : _qs;
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for (int i = 0; i < qs.size(); i++){
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if (var(qs[i]) != v){
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for (int j = 0; j < ps.size(); j++)
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if (var(ps[j]) == var(qs[i]))
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if (ps[j] == ~qs[i])
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return false;
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else
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goto next;
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out_clause.push(qs[i]);
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}
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next:;
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}
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for (int i = 0; i < ps.size(); i++)
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if (var(ps[i]) != v)
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out_clause.push(ps[i]);
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return true;
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}
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// Returns FALSE if clause is always satisfied.
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bool SimpSolver::merge(const Clause& _ps, const Clause& _qs, Var v, int& size)
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{
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merges++;
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bool ps_smallest = _ps.size() < _qs.size();
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const Clause& ps = ps_smallest ? _qs : _ps;
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const Clause& qs = ps_smallest ? _ps : _qs;
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const Lit* __ps = (const Lit*)ps;
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const Lit* __qs = (const Lit*)qs;
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size = ps.size()-1;
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for (int i = 0; i < qs.size(); i++){
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if (var(__qs[i]) != v){
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for (int j = 0; j < ps.size(); j++)
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if (var(__ps[j]) == var(__qs[i]))
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if (__ps[j] == ~__qs[i])
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return false;
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else
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goto next;
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size++;
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}
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next:;
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}
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return true;
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}
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void SimpSolver::gatherTouchedClauses()
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{
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if (n_touched == 0) return;
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int i,j;
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for (i = j = 0; i < subsumption_queue.size(); i++)
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if (ca[subsumption_queue[i]].mark() == 0)
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ca[subsumption_queue[i]].mark(2);
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for (i = 0; i < touched.size(); i++)
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if (touched[i]){
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const vec<CRef>& cs = occurs.lookup(i);
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for (j = 0; j < cs.size(); j++)
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if (ca[cs[j]].mark() == 0){
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subsumption_queue.insert(cs[j]);
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ca[cs[j]].mark(2);
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}
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touched[i] = 0;
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}
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for (i = 0; i < subsumption_queue.size(); i++)
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if (ca[subsumption_queue[i]].mark() == 2)
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ca[subsumption_queue[i]].mark(0);
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n_touched = 0;
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}
|
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bool SimpSolver::implied(const vec<Lit>& c)
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{
|
||
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assert(decisionLevel() == 0);
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trail_lim.push(trail.size());
|
||
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for (int i = 0; i < c.size(); i++)
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||
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if (value(c[i]) == l_True){
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cancelUntil(0);
|
||
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return false;
|
||
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}else if (value(c[i]) != l_False){
|
||
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assert(value(c[i]) == l_Undef);
|
||
|
uncheckedEnqueue(~c[i]);
|
||
|
}
|
||
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|
||
|
bool result = propagate() != CRef_Undef;
|
||
|
cancelUntil(0);
|
||
|
return result;
|
||
|
}
|
||
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|
||
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|
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// Backward subsumption + backward subsumption resolution
|
||
|
bool SimpSolver::backwardSubsumptionCheck(bool verbose)
|
||
|
{
|
||
|
int cnt = 0;
|
||
|
int subsumed = 0;
|
||
|
int deleted_literals = 0;
|
||
|
assert(decisionLevel() == 0);
|
||
|
|
||
|
while (subsumption_queue.size() > 0 || bwdsub_assigns < trail.size()){
|
||
|
|
||
|
// Empty subsumption queue and return immediately on user-interrupt:
|
||
|
if (asynch_interrupt){
|
||
|
subsumption_queue.clear();
|
||
|
bwdsub_assigns = trail.size();
|
||
|
break; }
|
||
|
|
||
|
// Check top-level assignments by creating a dummy clause and placing it in the queue:
|
||
|
if (subsumption_queue.size() == 0 && bwdsub_assigns < trail.size()){
|
||
|
Lit l = trail[bwdsub_assigns++];
|
||
|
ca[bwdsub_tmpunit][0] = l;
|
||
|
ca[bwdsub_tmpunit].calcAbstraction();
|
||
|
subsumption_queue.insert(bwdsub_tmpunit); }
|
||
|
|
||
|
CRef cr = subsumption_queue.peek(); subsumption_queue.pop();
|
||
|
Clause& c = ca[cr];
|
||
|
|
||
|
if (c.mark()) continue;
|
||
|
|
||
|
if (verbose && verbosity >= 2 && cnt++ % 1000 == 0)
|
||
|
printf("subsumption left: %10d (%10d subsumed, %10d deleted literals)\r", subsumption_queue.size(), subsumed, deleted_literals);
|
||
|
|
||
|
assert(c.size() > 1 || value(c[0]) == l_True); // Unit-clauses should have been propagated before this point.
|
||
|
|
||
|
// Find best variable to scan:
|
||
|
Var best = var(c[0]);
|
||
|
for (int i = 1; i < c.size(); i++)
|
||
|
if (occurs[var(c[i])].size() < occurs[best].size())
|
||
|
best = var(c[i]);
|
||
|
|
||
|
// Search all candidates:
|
||
|
vec<CRef>& _cs = occurs.lookup(best);
|
||
|
CRef* cs = (CRef*)_cs;
|
||
|
|
||
|
for (int j = 0; j < _cs.size(); j++)
|
||
|
if (c.mark())
|
||
|
break;
|
||
|
else if (!ca[cs[j]].mark() && cs[j] != cr && (subsumption_lim == -1 || ca[cs[j]].size() < subsumption_lim)){
|
||
|
Lit l = c.subsumes(ca[cs[j]]);
|
||
|
|
||
|
if (l == lit_Undef)
|
||
|
subsumed++, removeClause(cs[j]);
|
||
|
else if (l != lit_Error){
|
||
|
deleted_literals++;
|
||
|
|
||
|
if (!strengthenClause(cs[j], ~l))
|
||
|
return false;
|
||
|
|
||
|
// Did current candidate get deleted from cs? Then check candidate at index j again:
|
||
|
if (var(l) == best)
|
||
|
j--;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
return true;
|
||
|
}
|
||
|
|
||
|
|
||
|
bool SimpSolver::asymm(Var v, CRef cr)
|
||
|
{
|
||
|
Clause& c = ca[cr];
|
||
|
assert(decisionLevel() == 0);
|
||
|
|
||
|
if (c.mark() || satisfied(c)) return true;
|
||
|
|
||
|
trail_lim.push(trail.size());
|
||
|
Lit l = lit_Undef;
|
||
|
for (int i = 0; i < c.size(); i++)
|
||
|
if (var(c[i]) != v && value(c[i]) != l_False)
|
||
|
uncheckedEnqueue(~c[i]);
|
||
|
else
|
||
|
l = c[i];
|
||
|
|
||
|
if (propagate() != CRef_Undef){
|
||
|
cancelUntil(0);
|
||
|
asymm_lits++;
|
||
|
if (!strengthenClause(cr, l))
|
||
|
return false;
|
||
|
}else
|
||
|
cancelUntil(0);
|
||
|
|
||
|
return true;
|
||
|
}
|
||
|
|
||
|
|
||
|
bool SimpSolver::asymmVar(Var v)
|
||
|
{
|
||
|
assert(use_simplification);
|
||
|
|
||
|
const vec<CRef>& cls = occurs.lookup(v);
|
||
|
|
||
|
if (value(v) != l_Undef || cls.size() == 0)
|
||
|
return true;
|
||
|
|
||
|
for (int i = 0; i < cls.size(); i++)
|
||
|
if (!asymm(v, cls[i]))
|
||
|
return false;
|
||
|
|
||
|
return backwardSubsumptionCheck();
|
||
|
}
|
||
|
|
||
|
|
||
|
static void mkElimClause(vec<uint32_t>& elimclauses, Lit x)
|
||
|
{
|
||
|
elimclauses.push(toInt(x));
|
||
|
elimclauses.push(1);
|
||
|
}
|
||
|
|
||
|
|
||
|
static void mkElimClause(vec<uint32_t>& elimclauses, Var v, Clause& c)
|
||
|
{
|
||
|
int first = elimclauses.size();
|
||
|
int v_pos = -1;
|
||
|
|
||
|
// Copy clause to elimclauses-vector. Remember position where the
|
||
|
// variable 'v' occurs:
|
||
|
for (int i = 0; i < c.size(); i++){
|
||
|
elimclauses.push(toInt(c[i]));
|
||
|
if (var(c[i]) == v)
|
||
|
v_pos = i + first;
|
||
|
}
|
||
|
assert(v_pos != -1);
|
||
|
|
||
|
// Swap the first literal with the 'v' literal, so that the literal
|
||
|
// containing 'v' will occur first in the clause:
|
||
|
uint32_t tmp = elimclauses[v_pos];
|
||
|
elimclauses[v_pos] = elimclauses[first];
|
||
|
elimclauses[first] = tmp;
|
||
|
|
||
|
// Store the length of the clause last:
|
||
|
elimclauses.push(c.size());
|
||
|
}
|
||
|
|
||
|
|
||
|
|
||
|
bool SimpSolver::eliminateVar(Var v)
|
||
|
{
|
||
|
assert(!frozen[v]);
|
||
|
assert(!isEliminated(v));
|
||
|
assert(value(v) == l_Undef);
|
||
|
|
||
|
// Split the occurrences into positive and negative:
|
||
|
//
|
||
|
const vec<CRef>& cls = occurs.lookup(v);
|
||
|
vec<CRef> pos, neg;
|
||
|
for (int i = 0; i < cls.size(); i++)
|
||
|
(find(ca[cls[i]], mkLit(v)) ? pos : neg).push(cls[i]);
|
||
|
|
||
|
// Check wether the increase in number of clauses stays within the allowed ('grow'). Moreover, no
|
||
|
// clause must exceed the limit on the maximal clause size (if it is set):
|
||
|
//
|
||
|
int cnt = 0;
|
||
|
int clause_size = 0;
|
||
|
|
||
|
for (int i = 0; i < pos.size(); i++)
|
||
|
for (int j = 0; j < neg.size(); j++)
|
||
|
if (merge(ca[pos[i]], ca[neg[j]], v, clause_size) &&
|
||
|
(++cnt > cls.size() + grow || (clause_lim != -1 && clause_size > clause_lim)))
|
||
|
return true;
|
||
|
|
||
|
// Delete and store old clauses:
|
||
|
eliminated[v] = true;
|
||
|
setDecisionVar(v, false);
|
||
|
eliminated_vars++;
|
||
|
|
||
|
if (pos.size() > neg.size()){
|
||
|
for (int i = 0; i < neg.size(); i++)
|
||
|
mkElimClause(elimclauses, v, ca[neg[i]]);
|
||
|
mkElimClause(elimclauses, mkLit(v));
|
||
|
}else{
|
||
|
for (int i = 0; i < pos.size(); i++)
|
||
|
mkElimClause(elimclauses, v, ca[pos[i]]);
|
||
|
mkElimClause(elimclauses, ~mkLit(v));
|
||
|
}
|
||
|
|
||
|
|
||
|
// Produce clauses in cross product:
|
||
|
vec<Lit>& resolvent = add_tmp;
|
||
|
for (int i = 0; i < pos.size(); i++)
|
||
|
for (int j = 0; j < neg.size(); j++)
|
||
|
if (merge(ca[pos[i]], ca[neg[j]], v, resolvent) && !addClause_(resolvent))
|
||
|
return false;
|
||
|
|
||
|
for (int i = 0; i < cls.size(); i++)
|
||
|
removeClause(cls[i]);
|
||
|
|
||
|
// Free occurs list for this variable:
|
||
|
occurs[v].clear(true);
|
||
|
|
||
|
// Free watchers lists for this variable, if possible:
|
||
|
if (watches[ mkLit(v)].size() == 0) watches[ mkLit(v)].clear(true);
|
||
|
if (watches[~mkLit(v)].size() == 0) watches[~mkLit(v)].clear(true);
|
||
|
|
||
|
return backwardSubsumptionCheck();
|
||
|
}
|
||
|
|
||
|
|
||
|
bool SimpSolver::substitute(Var v, Lit x)
|
||
|
{
|
||
|
assert(!frozen[v]);
|
||
|
assert(!isEliminated(v));
|
||
|
assert(value(v) == l_Undef);
|
||
|
|
||
|
if (!ok) return false;
|
||
|
|
||
|
eliminated[v] = true;
|
||
|
setDecisionVar(v, false);
|
||
|
const vec<CRef>& cls = occurs.lookup(v);
|
||
|
|
||
|
vec<Lit>& subst_clause = add_tmp;
|
||
|
for (int i = 0; i < cls.size(); i++){
|
||
|
Clause& c = ca[cls[i]];
|
||
|
|
||
|
subst_clause.clear();
|
||
|
for (int j = 0; j < c.size(); j++){
|
||
|
Lit p = c[j];
|
||
|
subst_clause.push(var(p) == v ? x ^ sign(p) : p);
|
||
|
}
|
||
|
|
||
|
|
||
|
if (!addClause_(subst_clause))
|
||
|
return ok = false;
|
||
|
|
||
|
removeClause(cls[i]);
|
||
|
|
||
|
}
|
||
|
|
||
|
return true;
|
||
|
}
|
||
|
|
||
|
|
||
|
void SimpSolver::extendModel()
|
||
|
{
|
||
|
int i, j;
|
||
|
Lit x;
|
||
|
|
||
|
if(model.size()==0) model.growTo(nVars());
|
||
|
|
||
|
for (i = elimclauses.size()-1; i > 0; i -= j){
|
||
|
for (j = elimclauses[i--]; j > 1; j--, i--)
|
||
|
if (modelValue(toLit(elimclauses[i])) != l_False)
|
||
|
goto next;
|
||
|
|
||
|
x = toLit(elimclauses[i]);
|
||
|
model[var(x)] = lbool(!sign(x));
|
||
|
next:;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
|
||
|
bool SimpSolver::eliminate(bool turn_off_elim)
|
||
|
{
|
||
|
if (!simplify()) {
|
||
|
ok = false;
|
||
|
return false;
|
||
|
}
|
||
|
else if (!use_simplification)
|
||
|
return true;
|
||
|
|
||
|
// Main simplification loop:
|
||
|
//
|
||
|
|
||
|
int toPerform = clauses.size()<=4800000;
|
||
|
|
||
|
if(!toPerform) {
|
||
|
printf("c Too many clauses... No preprocessing\n");
|
||
|
}
|
||
|
|
||
|
while (toPerform && (n_touched > 0 || bwdsub_assigns < trail.size() || elim_heap.size() > 0)){
|
||
|
|
||
|
gatherTouchedClauses();
|
||
|
// printf(" ## (time = %6.2f s) BWD-SUB: queue = %d, trail = %d\n", cpuTime(), subsumption_queue.size(), trail.size() - bwdsub_assigns);
|
||
|
if ((subsumption_queue.size() > 0 || bwdsub_assigns < trail.size()) &&
|
||
|
!backwardSubsumptionCheck(true)){
|
||
|
ok = false; goto cleanup; }
|
||
|
|
||
|
// Empty elim_heap and return immediately on user-interrupt:
|
||
|
if (asynch_interrupt){
|
||
|
assert(bwdsub_assigns == trail.size());
|
||
|
assert(subsumption_queue.size() == 0);
|
||
|
assert(n_touched == 0);
|
||
|
elim_heap.clear();
|
||
|
goto cleanup; }
|
||
|
|
||
|
// printf(" ## (time = %6.2f s) ELIM: vars = %d\n", cpuTime(), elim_heap.size());
|
||
|
for (int cnt = 0; !elim_heap.empty(); cnt++){
|
||
|
Var elim = elim_heap.removeMin();
|
||
|
|
||
|
if (asynch_interrupt) break;
|
||
|
|
||
|
if (isEliminated(elim) || value(elim) != l_Undef) continue;
|
||
|
|
||
|
if (verbosity >= 2 && cnt % 100 == 0)
|
||
|
printf("elimination left: %10d\r", elim_heap.size());
|
||
|
|
||
|
if (use_asymm){
|
||
|
// Temporarily freeze variable. Otherwise, it would immediately end up on the queue again:
|
||
|
bool was_frozen = frozen[elim];
|
||
|
frozen[elim] = true;
|
||
|
if (!asymmVar(elim)){
|
||
|
ok = false; goto cleanup; }
|
||
|
frozen[elim] = was_frozen; }
|
||
|
|
||
|
// At this point, the variable may have been set by assymetric branching, so check it
|
||
|
// again. Also, don't eliminate frozen variables:
|
||
|
if (use_elim && value(elim) == l_Undef && !frozen[elim] && !eliminateVar(elim)){
|
||
|
ok = false; goto cleanup; }
|
||
|
|
||
|
checkGarbage(simp_garbage_frac);
|
||
|
}
|
||
|
|
||
|
assert(subsumption_queue.size() == 0);
|
||
|
}
|
||
|
cleanup:
|
||
|
|
||
|
// If no more simplification is needed, free all simplification-related data structures:
|
||
|
if (turn_off_elim){
|
||
|
touched .clear(true);
|
||
|
occurs .clear(true);
|
||
|
n_occ .clear(true);
|
||
|
elim_heap.clear(true);
|
||
|
subsumption_queue.clear(true);
|
||
|
|
||
|
use_simplification = false;
|
||
|
remove_satisfied = true;
|
||
|
ca.extra_clause_field = false;
|
||
|
|
||
|
// Force full cleanup (this is safe and desirable since it only happens once):
|
||
|
rebuildOrderHeap();
|
||
|
garbageCollect();
|
||
|
}else{
|
||
|
// Cheaper cleanup:
|
||
|
cleanUpClauses(); // TODO: can we make 'cleanUpClauses()' not be linear in the problem size somehow?
|
||
|
checkGarbage();
|
||
|
}
|
||
|
|
||
|
if (verbosity >= 0 && elimclauses.size() > 0)
|
||
|
printf("c | Eliminated clauses: %10.2f Mb |\n",
|
||
|
double(elimclauses.size() * sizeof(uint32_t)) / (1024*1024));
|
||
|
|
||
|
|
||
|
return ok;
|
||
|
|
||
|
|
||
|
}
|
||
|
|
||
|
|
||
|
void SimpSolver::cleanUpClauses()
|
||
|
{
|
||
|
occurs.cleanAll();
|
||
|
int i,j;
|
||
|
for (i = j = 0; i < clauses.size(); i++)
|
||
|
if (ca[clauses[i]].mark() == 0)
|
||
|
clauses[j++] = clauses[i];
|
||
|
clauses.shrink(i - j);
|
||
|
}
|
||
|
|
||
|
|
||
|
//=================================================================================================
|
||
|
// Garbage Collection methods:
|
||
|
|
||
|
|
||
|
void SimpSolver::relocAll(ClauseAllocator& to)
|
||
|
{
|
||
|
if (!use_simplification) return;
|
||
|
|
||
|
// All occurs lists:
|
||
|
//
|
||
|
for (int i = 0; i < nVars(); i++){
|
||
|
vec<CRef>& cs = occurs[i];
|
||
|
for (int j = 0; j < cs.size(); j++)
|
||
|
ca.reloc(cs[j], to);
|
||
|
}
|
||
|
|
||
|
// Subsumption queue:
|
||
|
//
|
||
|
for (int i = 0; i < subsumption_queue.size(); i++)
|
||
|
ca.reloc(subsumption_queue[i], to);
|
||
|
|
||
|
// Temporary clause:
|
||
|
//
|
||
|
ca.reloc(bwdsub_tmpunit, to);
|
||
|
}
|
||
|
|
||
|
|
||
|
void SimpSolver::garbageCollect()
|
||
|
{
|
||
|
// Initialize the next region to a size corresponding to the estimated utilization degree. This
|
||
|
// is not precise but should avoid some unnecessary reallocations for the new region:
|
||
|
ClauseAllocator to(ca.size() - ca.wasted());
|
||
|
|
||
|
cleanUpClauses();
|
||
|
to.extra_clause_field = ca.extra_clause_field; // NOTE: this is important to keep (or lose) the extra fields.
|
||
|
relocAll(to);
|
||
|
Solver::relocAll(to);
|
||
|
if (verbosity >= 2)
|
||
|
printf("| Garbage collection: %12d bytes => %12d bytes |\n",
|
||
|
ca.size()*ClauseAllocator::Unit_Size, to.size()*ClauseAllocator::Unit_Size);
|
||
|
to.moveTo(ca);
|
||
|
}
|