@Override
public Object visit(RealBinaryExpression n, Void arg) {
Double leftDouble = (Double) n.getLeftOperand().accept(this, null);
Double rightDouble = (Double) n.getRightOperand().accept(this, null);
double leftVal = leftDouble.doubleValue();
double rightVal = rightDouble.doubleValue();
Operator op = n.getOperator();
switch (op) {
case DIV:
return leftVal / rightVal;
case MUL:
return leftVal * rightVal;
case MINUS:
return leftVal - rightVal;
case PLUS:
return leftVal + rightVal;
case REM:
return leftVal % rightVal;
case ATAN2:
return Math.atan2(leftVal, rightVal);
case COPYSIGN:
return Math.copySign(leftVal, rightVal);
case HYPOT:
return Math.hypot(leftVal, rightVal);
case IEEEREMAINDER:
return Math.IEEEremainder(leftVal, rightVal);
case MAX:
return Math.max(leftVal, rightVal);
case MIN:
return Math.min(leftVal, rightVal);
case NEXTAFTER:
return Math.nextAfter(leftVal, rightVal);
case POW:
return Math.pow(leftVal, rightVal);
case SCALB:
return Math.scalb(leftVal, (int) rightVal);
default:
log.warn("IntegerBinaryExpression: unimplemented operator: " + op);
return null;
}
}
@Override
public Double next() {
double diff = to - from;
double next = from + diff * workingRandom.nextDouble();
if (next >= to) {
// Rounding error occurred
next = Math.nextAfter(next, Double.NEGATIVE_INFINITY);
}
return next;
}
@Override
public int compare(DataKeyValue o1, DataKeyValue o2) {
int cmp;
// ensure we have DataKeyValue objects...
if (o1 == null) {
return (o2 == null) ? 0 : -1;
}
if (o2 == null) {
return 1;
}
// ensure we have matching column names...
if (o1.column == null) {
// value is meaningless if no column name...
return (o2.column == null) ? 0 : -1;
}
cmp = o1.column.compareTo(o2.column);
if (cmp != 0) {
// column names do not match
return cmp;
}
// ensure we have non-null values...
if (o1.value == null) {
return (o2.value == null) ? 0 : -1;
}
if (o2.value == null) {
return 1;
}
cmp = o1.value.compareTo(o2.value);
if (cmp == 0) {
// common case...
return 0;
}
// Argh! we need to deal with possible numeric representation
// problems...
ElementDataType dt = columnMap.get(o1.column);
if (dt == ElementDataType.number) {
// special case of numeric data.
// !!Important!! Double.valueOf(str) handles NaN and +/-Infinity
Double localNumber = Double.valueOf(o1.value);
Double serverNumber = Double.valueOf(o2.value);
if (localNumber.equals(serverNumber)) {
// simple case -- trailing zeros or string representation mix-up
//
return 0;
} else if (localNumber.isInfinite() && serverNumber.isInfinite()) {
// if they are both plus or both minus infinity, we have a match
if (Math.signum(localNumber) == Math.signum(serverNumber)) {
return 0;
} else {
return (Math.signum(localNumber) < 0.0) ? -1 : 1;
}
} else if (localNumber.isNaN() && serverNumber.isNaN()) {
// can't distinguish them...
return 0;
} else if (localNumber.isNaN()) {
// NaN less than infinities...
return -1;
} else if (serverNumber.isNaN()) {
return 1;
} else if (localNumber.isInfinite()) {
// infinity is high or low, based upon its sign
return (Math.signum(localNumber) < 0.0) ? -1 : 1;
} else if (serverNumber.isInfinite()) {
return (Math.signum(serverNumber) < 0.0) ? 1 : -1;
} else {
double localDbl = localNumber;
double serverDbl = serverNumber;
if (localDbl == serverDbl) {
// should handle two values like 9.80 and 9.8
// but equals() earlier should also handle this.
return 0;
}
// We have two values that may be like:
// 9.8+epsilon and 9.8
// consider them equal if they are within 2 steps of
// each other. Deals with differing double-to-string
// and string-to-double conversion libraries across
// platforms and languages.
double localNear = localDbl;
int idist = 0;
int idistMax = 2;
for (idist = 0; idist < idistMax; ++idist) {
localNear = Math.nextAfter(localNear, serverDbl);
if (localNear == serverDbl) {
break;
}
}
if (idist < idistMax) {
return 0;
}
return localNumber.compareTo(serverNumber);
}
}
// otherwise, return whatever the string compare gave...
return cmp;
}
/**
* Evolves the specified variables using the SBX operator.
*
* @param v1 the first variable
* @param v2 the second variable
* @param distributionIndex the distribution index of this SBX operator
*/
public void evolve(RealVariable v1, RealVariable v2, double distributionIndex) {
double x0 = v1.getValue();
double x1 = v2.getValue();
double dx = Math.abs(x1 - x0);
if (dx > Settings.EPS) {
double lb = v1.getLowerBound();
double ub = v1.getUpperBound();
double bl;
double bu;
if (x0 < x1) {
bl = 1 + 2 * (x0 - lb) / dx;
bu = 1 + 2 * (ub - x1) / dx;
} else {
bl = 1 + 2 * (x1 - lb) / dx;
bu = 1 + 2 * (ub - x0) / dx;
}
// use symmetric distributions
if (bl < bu) {
bu = bl;
} else {
bl = bu;
}
double p_bl = 1 - 1 / (2 * Math.pow(bl, distributionIndex + 1));
double p_bu = 1 - 1 / (2 * Math.pow(bu, distributionIndex + 1));
double u = pprng.nextDouble();
// prevent out-of-bounds values if PRNG draws the value 1.0
if (u == 1.0) {
u = Math.nextAfter(u, -1.0);
}
double u0 = u * p_bl;
double u1 = u * p_bu;
double b0;
double b1;
if (u0 <= 0.5) {
b0 = Math.pow(2 * u0, 1 / (distributionIndex + 1));
} else {
b0 = Math.pow(0.5 / (1 - u0), 1 / (distributionIndex + 1));
}
if (u1 <= 0.5) {
b1 = Math.pow(2 * u1, 1 / (distributionIndex + 1));
} else {
b1 = Math.pow(0.5 / (1 - u1), 1 / (distributionIndex + 1));
}
if (x0 < x1) {
v1.setValue(0.5 * (x0 + x1 + b0 * (x0 - x1)));
v2.setValue(0.5 * (x0 + x1 + b1 * (x1 - x0)));
} else {
v1.setValue(0.5 * (x0 + x1 + b1 * (x0 - x1)));
v2.setValue(0.5 * (x0 + x1 + b0 * (x1 - x0)));
}
// this makes PISA's SBX compatible with other implementations
// which swap the values
if (pprng.nextBoolean()) {
double temp = v1.getValue();
v1.setValue(v2.getValue());
v2.setValue(temp);
}
// guard against out-of-bounds values
if (v1.getValue() < lb) {
v1.setValue(lb);
} else if (v1.getValue() > ub) {
v1.setValue(ub);
}
if (v2.getValue() < lb) {
v2.setValue(lb);
} else if (v2.getValue() > ub) {
v2.setValue(ub);
}
}
}
@MethodSubstitution(isStatic = true)
static double nextAfter(double x, double d) {
double xx = (x == -0.0 ? 0.0 : x);
return Math.nextAfter(xx, d);
}
static double nextAfter(double x, double d) {
return Math.nextAfter(x, d);
}
static double next2(double v) {
return Math.nextAfter(v, 1.0);
}