/**
* Creates a stream of pseudo random numbers following a Hypergeometrical distribution. The
* specific parameters N (set size), n (marked amount) and k (subset size) have to be given here
* at creation time.
*
* @param owner Model : The distribution's owner
* @param name java.lang.String : The distribution's name
* @param setSize int : The size of the underlying set.
* @param markedAmount int : The amount of marked objects within the underlying set.
* @param subsetSize int : The size of the random subset of the underlying set.
* @param showInReport boolean : Flag for producing reports
* @param showInTrace boolean : Flag for producing trace output
*/
public DiscreteDistHypergeo(
Model owner,
String name,
int setSize,
int markedAmount,
int subsetSize,
boolean showInReport,
boolean showInTrace) {
super(owner, name, showInReport, showInTrace);
this.setSize = setSize;
this.markedAmount = markedAmount;
this.subsetSize = subsetSize;
valueList = new ArrayList<Entry>();
Entry e;
HypergeometricDistribution hgdist =
new HypergeometricDistributionImpl(setSize, markedAmount, subsetSize);
for (int i = 0; i <= this.subsetSize; i++) {
try {
e = new Entry(i, hgdist.cumulativeProbability(i));
valueList.add(e);
} catch (MathException e1) {
sendWarning(
"Failed to compute cumulative Probability of value "
+ Integer.toString(i)
+ ", entry ignored",
"CustomContDist : " + getName() + " at construction time",
"Impossible to compute cumulative Probability",
"Make sure the subset size as well as the amount of successes are smaller than the main set size");
}
}
}
/**
* @param param population size
* @param param2 number of successes
* @param param3 sample size
* @return hypergeometric distribution
*/
protected HypergeometricDistribution getHypergeometricDistribution(
int param, int param2, int param3) {
if (hypergeometric == null
|| hypergeometric.getNumberOfSuccesses() != param2
|| hypergeometric.getPopulationSize() != param
|| hypergeometric.getSampleSize() != param3)
hypergeometric = new HypergeometricDistributionImpl(param, param2, param3);
return hypergeometric;
}
public static double probabilty(
int backgroundChipSize, int countOnBackground, int filterSetSize, int countFiltered) {
// create the distribution
HypergeometricDistribution dist =
factory.createHypergeometricDistribution(
backgroundChipSize, countOnBackground, filterSetSize);
// return the probability
return dist.probability(countFiltered);
}