/**
* Return a list of indices representing the next values that would be selected using the given
* probabilities
*/
public IntegerVector getNextIndicesDeterministicallyUsingProbs(DoubleVector probs) {
// Check the number of indices is equal to number of probabilities
if (size() != probs.size()) {
throw new ErrorException(
"Number of probabilities ("
+ probs.size()
+ ") does not match the receiver ("
+ size()
+ ")");
}
// Calculate the total number of samples for this selection (One more than the sum of the counts
// so far)
double n = 0;
double cumProb = 0.0;
for (int i = 0; i < size(); i++) {
n += get(i);
cumProb += probs.get(i);
}
double x = n + 1;
if (Math.abs(cumProb - 1.0) > 0.001) {
throw new ErrorException("Probabilities do not sum to 1.000");
}
// Loop through indices
IntegerVector sortedIndices = new IntegerVector();
DoubleVector sortedDiffs = new DoubleVector();
for (int i = 0; i < probs.size(); i++) {
// Calculate the expected number of events for this probability
double expectedNumber = x * probs.get(i);
// Select the index with the largest difference between the current
// number and the expected number of events
double difference = expectedNumber - get(i);
int destIndex = 0;
for (int j = 0; j < sortedDiffs.size(); j++) {
if (sortedDiffs.get(j) < difference) {
break;
}
destIndex++;
}
sortedDiffs.add(destIndex, difference);
sortedIndices.add(destIndex, i);
}
return sortedIndices;
}
/**
* Select indices deterministically from the given probability distribution. The float buffer
* receiver of this method is the number of times that each index has been fully selected. The
* given split determines how many distinct indices will be selected, and by how much they will be
* incremented (the total increments add up to one). The same index can be selected twice.
*/
public IntegerVector selectIndicesDeterministicallyUsingProbs_SplitAllowDuplicateIndex(
DoubleVector probs, DoubleVector split) {
double n;
double maxDifference;
double cumProb;
double expectedNumber;
double difference;
int selectedIndex;
IntegerVector selectedIndices;
// Check that the number of indices is equal to the number of probabilities
if (!(this.size() == probs.size())) {
throw new ErrorException("Number of probabilities does not match the number the receiver");
}
// Check that there is a valid split
if (split.size() == 0) {
throw new ErrorException("No split given");
}
/*else {
if( Math.abs( (split.sum() - 1.0) ) > 0.001 ) {
throw new ErrorException( "Split does not sum to 1.0" );
}
}*/
selectedIndices = new IntegerVector(1, 1);
// Calculate the total number of samples for this selection so far
n = 0.0;
cumProb = 0.0;
for (int j = 1; j <= this.size(); j++) {
n = (n + this.get(j - 1));
cumProb = (cumProb + probs.get(j - 1));
}
if (Math.abs((cumProb - 1.0)) > 0.001) {
throw new ErrorException("Probabilities do not sum to 1.000");
}
for (int i = 1; i <= split.size(); i++) {
n = (n + split.get(i - 1));
// Loop through the indices
maxDifference = -100000.0;
selectedIndex = 0;
for (int j = 1; j <= probs.size(); j++) {
if (probs.get(j - 1) > 0.0) {
// Calculate the expected number of events for this
// probability
expectedNumber = (n * probs.get(j - 1));
// Select the index with the largest difference between
// the current number and the expected number of events
difference = (expectedNumber - this.get(j - 1));
if (!(maxDifference + 1.0E-10 >= difference)) {
maxDifference = difference;
selectedIndex = j;
}
}
}
if (selectedIndex == 0) {
throw new ErrorException("Error in method");
}
// Increment the count for this index
this.addAt(split.get(i - 1), selectedIndex - 1);
selectedIndices.add(selectedIndex);
}
return selectedIndices;
}
