Example usage for weka.core ContingencyTables symmetricalUncertainty

Introduction

In this page you can find the example usage for weka.core ContingencyTables symmetricalUncertainty.

Prototype

public static double symmetricalUncertainty(double matrix[][]) 

Source Link

Document

Calculates the symmetrical uncertainty for base 2.

Usage

From source file:moa.reduction.bayes.IncrInfoThAttributeEval.java

License:Open Source License

@Override
/**/* w  ww .  j a v  a 2  s  .  c  om*/
 * Update the contingency tables and the rankings for each features using the counters.
 * Counters are updated in each iteration.
 */
public void applySelection() {
    if (counts != null && updated) {
        m_InfoValues = new double[counts.length];
        for (int i = 0; i < counts.length; i++) {
            if (i != classIndex) {
                Set<Key> keys = counts[i].keySet();
                Set<Entry<Key, Float>> entries = counts[i].entrySet();

                Set<Float> avalues = new HashSet<Float>();
                Set<Float> cvalues = new HashSet<Float>();
                for (Iterator<Key> it = keys.iterator(); it.hasNext();) {
                    Key key = it.next();
                    avalues.add(key.x);
                    cvalues.add(key.y);
                }

                Map<Float, Integer> apos = new HashMap<Float, Integer>();
                Map<Float, Integer> cpos = new HashMap<Float, Integer>();

                int aidx = 0;
                for (Iterator<Float> it = avalues.iterator(); it.hasNext();) {
                    Float f = it.next();
                    apos.put(f, aidx++);
                }

                int cidx = 0;
                for (Iterator<Float> it = cvalues.iterator(); it.hasNext();) {
                    Float f = it.next();
                    cpos.put(f, cidx++);
                }

                double[][] lcounts = new double[avalues.size()][cvalues.size()];
                for (Iterator<Entry<Key, Float>> it = entries.iterator(); it.hasNext();) {
                    Entry<Key, Float> entry = it.next();
                    lcounts[apos.get(entry.getKey().x)][cpos.get(entry.getKey().y)] = entry.getValue();
                }

                switch (method) {
                case 1:
                    m_InfoValues[i] = ContingencyTables.symmetricalUncertainty(lcounts);
                    break;

                default:
                    m_InfoValues[i] = (ContingencyTables.entropyOverColumns(lcounts)
                            - ContingencyTables.entropyConditionedOnRows(lcounts));
                    break;
                }
            }
        }
        //System.out.println("Attribute values: " + Arrays.toString(m_InfoValues));
        updated = false;
    }
}

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