public double getDoubleValue(int valueIndex) {
BitString clear = getClearBitCode(valueIndex);
double f = 1.0;
double val = 0.0;
for (int i = getPrecision() - 1; i >= 1; i--, f *= 2.0) val += (clear.get(i) ? 1.0 : 0.0) * f;
if (clear.get(0)) val = -val;
val /= decimalScale;
return val;
}
public void setDoubleValue(int valueIndex, double value) {
double setVal = Math.rint(value * decimalScale);
if (setVal >= Long.MAX_VALUE || setVal <= Long.MIN_VALUE)
throw new IllegalArgumentException("Absolute decimal value too big");
BitString clear = new BitString(getPrecision());
clear.set(0, setVal < 0);
setVal = Math.abs(setVal);
double f = 1.0;
for (int i = getPrecision() - 1; i >= 1; i--, f *= 2.0) clear.set(i, (setVal % (2.0 * f) >= f));
setClearBitCode(valueIndex, clear);
}
public Individual[] reproduce(Individual[] parents, GAParameterSet params) {
if (parents.length != getRequiredNumberOfParents())
throw new IllegalArgumentException(
"Need "
+ getRequiredNumberOfParents()
+ " parents for reproduction (not "
+ parents.length
+ ")");
// Check correct type for parents, get length:
int bitLen = checkParentsTypeAndLength(parents);
// Chance (1 - xover probability) that parents wont be changed:
final RandomGenerator rnd = params.getRandomGenerator();
if (rnd.nextDouble() >= getXOverProbability()) return makeCopyOfParents(parents, params);
// Get parents bitsrings:
BitString p1 = ((BinaryEncodedIndividual) parents[0]).getBitStringRepresentation();
BitString p2 = ((BinaryEncodedIndividual) parents[1]).getBitStringRepresentation();
// x-over:
final int maxAttempts = params.getMaxBadReproductionAttempts();
int attempts = 0;
boolean kidsAreValid = false;
do {
kidsAreValid = false;
int xPoint = rnd.nextInt(1, bitLen);
// offspring bit strings:
BitString c1 = new BitString(bitLen);
BitString c2 = new BitString(bitLen);
// copy before xover-point:
for (int i = 0; i < xPoint; i++) {
c1.set(i, p1.get(i));
c2.set(i, p2.get(i));
}
// copy after xover-point:
for (int i = xPoint; i < bitLen; i++) {
c1.set(i, p2.get(i));
c2.set(i, p1.get(i));
}
// create children and check if children are valid:
ClassifierIndividual[] kids = createKidsFromEncoding(params, c1, c2);
kidsAreValid = kidsSatisfyConstraints(kids, params);
// return valid kids or have another attempts:
if (kidsAreValid) return kids;
else attempts++;
} while (!kidsAreValid && attempts < maxAttempts);
// all attempts failed:
return makeCopyOfParents(parents, params);
}
