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| ILits | Line # 48 | 0 | 1 | - |
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| 1 | /* | |
| 2 | * SAT4J: a SATisfiability library for Java Copyright (C) 2004-2006 Daniel Le Berre | |
| 3 | * | |
| 4 | * Based on the original minisat specification from: | |
| 5 | * | |
| 6 | * An extensible SAT solver. Niklas E?n and Niklas S?rensson. Proceedings of the | |
| 7 | * Sixth International Conference on Theory and Applications of Satisfiability | |
| 8 | * Testing, LNCS 2919, pp 502-518, 2003. | |
| 9 | * | |
| 10 | * This library is free software; you can redistribute it and/or modify it under | |
| 11 | * the terms of the GNU Lesser General Public License as published by the Free | |
| 12 | * Software Foundation; either version 2.1 of the License, or (at your option) | |
| 13 | * any later version. | |
| 14 | * | |
| 15 | * This library is distributed in the hope that it will be useful, but WITHOUT | |
| 16 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | |
| 17 | * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more | |
| 18 | * details. | |
| 19 | * | |
| 20 | * You should have received a copy of the GNU Lesser General Public License | |
| 21 | * along with this library; if not, write to the Free Software Foundation, Inc., | |
| 22 | * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| 23 | * | |
| 24 | */ | |
| 25 | ||
| 26 | package org.sat4j.minisat.core; | |
| 27 | ||
| 28 | import org.sat4j.specs.IVec; | |
| 29 | ||
| 30 | /** | |
| 31 | * That interface manages the solver's internal vocabulary. Everything related | |
| 32 | * to variables and literals is available from here. | |
| 33 | * | |
| 34 | * For sake of efficiency, literals and variables are not object in SAT4J. They | |
| 35 | * are represented by numbers. If the vocabulary contains n variables, then | |
| 36 | * variables should be accessed by numbers from 1 to n and literals by numbers | |
| 37 | * from 2 to 2*n+1. | |
| 38 | * | |
| 39 | * For a Dimacs variable v, the variable index in SAT4J is v, it's positive | |
| 40 | * literal is 2*v (v << 1) and it's negative literal is 2*v+1 ((v<<1)^1). | |
| 41 | * Note that one can easily access to the complementary literal of p by using | |
| 42 | * bitwise operation ^. | |
| 43 | * | |
| 44 | * In SAT4J, literals are usualy denoted by p or q and variables by v or x. | |
| 45 | * | |
| 46 | * @author leberre | |
| 47 | */ | |
| 48 | public interface ILits { | |
| 49 | ||
| 50 | public static int UNDEFINED = -1; | |
| 51 | ||
| 52 | public abstract void init(int nvar); | |
| 53 | ||
| 54 | /** | |
| 55 | * Translates a Dimacs literal into an internal representation literal. | |
| 56 | * | |
| 57 | * @param x | |
| 58 | * the Dimacs literal (a non null integer). | |
| 59 | * @return the literal in the internal representation. | |
| 60 | */ | |
| 61 | public abstract int getFromPool(int x); | |
| 62 | ||
| 63 | /** | |
| 64 | * Returns true iff the variable is used in the set of constraints. | |
| 65 | * | |
| 66 | * @param x | |
| 67 | * @return true iff the variable belongs to the formula. | |
| 68 | */ | |
| 69 | boolean belongsToPool(int x); | |
| 70 | ||
| 71 | public abstract void resetPool(); | |
| 72 | ||
| 73 | public abstract void ensurePool(int howmany); | |
| 74 | ||
| 75 | public abstract void unassign(int lit); | |
| 76 | ||
| 77 | public abstract void satisfies(int lit); | |
| 78 | ||
| 79 | public abstract boolean isSatisfied(int lit); | |
| 80 | ||
| 81 | public abstract boolean isFalsified(int lit); | |
| 82 | ||
| 83 | public abstract boolean isUnassigned(int lit); | |
| 84 | ||
| 85 | /** | |
| 86 | * @param lit | |
| 87 | * @return true iff the truth value of that literal is due to a unit | |
| 88 | * propagation or a decision. | |
| 89 | */ | |
| 90 | public abstract boolean isImplied(int lit); | |
| 91 | ||
| 92 | /** | |
| 93 | * to obtain the max id of the variable | |
| 94 | * | |
| 95 | * @return the maximum number of variables in the formula | |
| 96 | */ | |
| 97 | public abstract int nVars(); | |
| 98 | ||
| 99 | /** | |
| 100 | * to obtain the real number of variables appearing in the formula | |
| 101 | * | |
| 102 | * @return the number of variables used in the pool | |
| 103 | */ | |
| 104 | int realnVars(); | |
| 105 | ||
| 106 | public abstract int not(int lit); | |
| 107 | ||
| 108 | public abstract void reset(int lit); | |
| 109 | ||
| 110 | public abstract int getLevel(int lit); | |
| 111 | ||
| 112 | public abstract void setLevel(int lit, int l); | |
| 113 | ||
| 114 | public abstract Constr getReason(int lit); | |
| 115 | ||
| 116 | public abstract void setReason(int lit, Constr r); | |
| 117 | ||
| 118 | public abstract IVec<Undoable> undos(int lit); | |
| 119 | ||
| 120 | public abstract void watch(int lit, Propagatable c); | |
| 121 | ||
| 122 | /** | |
| 123 | * @param lit | |
| 124 | * a literal | |
| 125 | * @return the list of all the constraints that watch the negation of lit | |
| 126 | */ | |
| 127 | public abstract IVec<Propagatable> watches(int lit); | |
| 128 | ||
| 129 | public abstract String valueToString(int lit); | |
| 130 | } | |
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