protected final int getLasVegasCoef(int i) {
// <hca> I round it to PRECISION because of issues between versions of the jvm on mac and pc
final double log = MathUtils.roundedLog(i * divFactor + 1, geometricalIntFactor);
final int k = (int) Math.floor(log);
if (log == k) {
return MathUtils.pow(geometricalIntFactor, k - 1);
} else {
// recursion
return getLasVegasCoef(i - geometricalSum(geometricalIntFactor, k));
}
}
protected boolean propagateNewUpperBound(int myub) throws ContradictionException {
Explanation expl = this.explainVariablesUB();
boolean anyChange = false;
int nbVars = getNbVars();
if (myub < 0) {
AbstractIntSConstraint.logger.finer("ub = " + myub + " < 0 => fail");
((ExplainedSolver) this.getProblem()).explainedFail(expl);
}
int i;
for (i = 0; i < nbPosVars; i++) {
int newInfi = MathUtils.divCeil(-(myub), coeffs[i]) + vars[i].getSup();
if (((ExplainedIntVar) vars[i]).updateInf(newInfi, cIndices[i], expl)) {
AbstractIntSConstraint.logger.finer(
"INF("
+ vars[i].toString()
+ ") >= "
+ -(myub)
+ "/"
+ coeffs[i]
+ " + "
+ vars[i].getSup()
+ " = "
+ newInfi);
anyChange = true;
}
}
for (i = nbPosVars; i < nbVars; i++) {
int newSupi = MathUtils.divFloor(myub, -(coeffs[i])) + vars[i].getInf();
if (((ExplainedIntVar) vars[i]).updateSup(newSupi, cIndices[i], expl)) {
AbstractIntSConstraint.logger.finer(
"SUP("
+ vars[i].toString()
+ ") <= "
+ myub
+ "/"
+ -(coeffs[i])
+ " + "
+ vars[i].getInf()
+ " = "
+ newSupi);
anyChange = true;
}
}
return anyChange;
}
private static final int geometricalSum(int value, int exponent) {
return (MathUtils.pow(value, exponent) - 1) / (value - 1);
}