// Computes the least common multiple of the two simple expression.
// Assumes se1 and se2 have been normalized.
private static SimpleExpression computeLCM(SimpleExpression se1, SimpleExpression se2) {
se1 = se1.factorize();
se2 = se2.factorize();
List<SimpleExpression> gcd = computeGCD(se1, se2);
SimpleExpression ret = multiply(gcd.get(0), gcd.get(1));
ret = multiply(ret, gcd.get(2));
return ret;
}
// Normalizes a MOD expression
private SimpleExpression normalizeMOD() {
if (!allow(DIVIDE)) return this;
SimpleExpression lhs = getChild(0), rhs = getChild(1), ret = null;
if (rhs.equals(szero)) ret = this;
else if (lhs.sop == LIT && rhs.sop == LIT) ret = mod(lhs, rhs);
else if (rhs.equals(sone) || rhs.equals(getInt(-1))) ret = szero;
if (ret == null) {
lhs = lhs.factorize();
rhs = rhs.factorize();
List<SimpleExpression> gcd = computeGCD(lhs, rhs);
if (gcd.get(0).equals(sone)) ret = this;
else // (a*x)%(b*x) = (a%b)*x
ret = multiply(gcd.get(0), new SimpleExpression(gcd.get(1), MOD, gcd.get(2)));
}
// Tools.printlnStatus("[MOD] "+this+" --> "+ret, 1);
return ret;
}
// Normalizes a DIV expression
private SimpleExpression normalizeDIV() {
if (!allow(DIVIDE)) return this;
SimpleExpression lhs = getChild(0), rhs = getChild(1), ret = null;
if (rhs.equals(szero)) ret = this; // Don't do anything with division by zero
else if (lhs.equals(szero)) ret = szero; // 0/<expr>: expr=0 is an exception anyhow
else if (lhs.sop == LIT && rhs.sop == LIT) ret = divide(lhs, rhs); // Call compute method
else if (rhs.equals(sone) || rhs.equals(getInt(-1)))
ret = multiply(rhs, lhs); // Division by one -> multiplication by one
if (ret == null) {
lhs = lhs.factorize();
rhs = rhs.factorize();
List<SimpleExpression> gcd = computeGCD(lhs, rhs);
if (gcd.get(0).equals(sone)) ret = this;
else ret = divide(gcd.get(1), gcd.get(2));
}
// Tools.printlnStatus("[DIV] "+this+" --> "+ret, 1);
return ret;
}