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| package org.sat4j.ubcsat.algorithms; |
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| import org.sat4j.ubcsat.Random; |
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| import org.sat4j.ubcsat.lit.Lits; |
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| import org.sat4j.ubcsat.triggers.VarScore; |
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| public class PickGSatSimple implements IAlgorithm { |
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| private int iNumCandidates; |
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| private int[] aCandidateList; |
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| private int iInitVarFlip = 0; |
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| public void init(int nVars) {
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0
| if (iInitVarFlip > 0) {
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| for (int j = 0; j < iInitVarFlip; j++) {
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| int iVar;
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| boolean bAdded = true;
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| do {
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| iVar = (int) Random.randomInt(nVars) + 1;
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| if (j > 0) {
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| for (int k = 0; k < j; k++) {
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| if (aCandidateList[k] == iVar) {
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| bAdded = false;
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| break;
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| } |
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| } |
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| } |
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| } while (!bAdded);
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| aCandidateList[j] = iVar;
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| Lits.aVarValue[iVar] = 1 - Lits.aVarValue[iVar];
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| } |
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| } |
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| } |
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| public void selectVariableToFlip(int nClauses, int nVars, VarScore score) {
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| long iScore;
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| iNumCandidates = 0;
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| if (aCandidateList == null) {
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| aCandidateList = new int[nVars];
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| } |
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| long iBestScore = nClauses;
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| for (int j = 1; j <= nVars; j++) {
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| iScore = score.aVarScore[j];
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| if (iScore <= iBestScore) {
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| if (iScore < iBestScore) {
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| iNumCandidates = 0;
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| iBestScore = iScore;
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| } |
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| aCandidateList[iNumCandidates++] = j;
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| } |
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| } |
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| if (iNumCandidates > 1) {
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| score.iFlipCandidate = aCandidateList[(int) Random
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| .randomInt(iNumCandidates)]; |
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| } else { |
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| score.iFlipCandidate = aCandidateList[0];
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| } |
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| } |
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| } |
