package hep.aida.util.comparison;

import hep.aida.ext.IComparisonData;

/**
 *
 * @author The FreeHEP team @ SLAC.
 * Algorithm taken from http://www.ge.infn.it/geant4/analysis/HEPstatistics/
 *
 */
public class AndersonDarlingComparisonAlgorithm extends AbstractComparisonAlgorithm {

    private static final String[] names = new String[] {"AndersonDarling","AD"};
    private static final int dType = ANY_DATA;
    private static final int eType = ANY_NUMBER_OF_EVENTS;

    private static final double[] rejectionValues = new double[] {0.1, 0.05, 0.01, 0.001};
    private static final double[] criticalValues = new double[] {1.933, 2.492, 3.857, 4.356};
    
    public AndersonDarlingComparisonAlgorithm() {
        super(dType, eType);
    }

    public void setRejectionLevel() {
        super.setRejectionLevel();
        double aL = rejectionLevel();
        boolean found = false;
        for ( int i = 0; i < rejectionValues.length; i++ )
            if ( aL == rejectionValues[i]) {
                found = true;
                break;
            }
        if ( ! found ) {
            String levels = "";
            for ( int i = 0; i < rejectionValues.length; i++ )
                levels += rejectionValues[i]+" ";
            System.out.println("Algorithm "+algorithmNames()[0]+" can currently support ONLY the following rejection levels: "+levels);
        }
    }
    
    public double matchLowerBound() {
        return 0;
    }
    
    public double matchUpperBound() {
        double aL = rejectionLevel();
        for ( int i = 0; i < rejectionValues.length; i++ )
            if ( aL == rejectionValues[i])
                return criticalValues[i];
        return criticalValues[1];
    }
    
    public double quality(IComparisonData d1, IComparisonData d2) {
        
        if ( d1.type() != d2.type() )
            throw new IllegalArgumentException("Incompatible data sets: one is binned the other is unbinned. Cannot perform test");

        int nPoints1 = d1.nPoints();
        int nPoints2 = d2.nPoints();
        
        // Calculate the sum of weights
        double sumOfWeights1=0.,sumOfWeights2=0.;
        for(int i=0; i