All Packages  Class Hierarchy  This Package  Previous  Next  Index  WEKA's home

Class weka.core.ContingencyTables

java.lang.Object
    |
    +----weka.core.ContingencyTables

public class ContingencyTables
extends java.lang.Object
Class implementing some statistical routines for contingency tables.

Version:
$Revision: 1.4 $
Author:
Eibe Frank (eibe@cs.waikato.ac.nz)

Constructor Index

 o ContingencyTables()
 

Method Index

 o chiSquared(double[][], boolean)
Returns chi-squared probability for a given matrix.
 o chiVal(double[][], boolean)
Computes chi-squared statistic for a contingency table.
 o cochransCriterion(double[][])
Tests if Cochran's criterion is fullfilled for the given contingency table.
 o CramersV(double[][])
Computes Cramer's V for a contingency table.
 o entropy(double[])
Computes the entropy of the given array.
 o entropyConditionedOnColumns(double[][])
Computes conditional entropy of the rows given the columns.
 o entropyConditionedOnRows(double[][])
Computes conditional entropy of the columns given the rows.
 o entropyConditionedOnRows(double[][], double[][], double)
Computes conditional entropy of the columns given the rows of the test matrix with respect to the train matrix.
 o entropyOverColumns(double[][])
Computes the columns' entropy for the given contingency table.
 o entropyOverRows(double[][])
Computes the rows' entropy for the given contingency table.
 o gainRatio(double[][])
Computes gain ratio for contingency table (split on rows).
 o log2MultipleHypergeometric(double[][])
Returns negative base 2 logarithm of multiple hypergeometric probability for a contingency table.
 o main(String[])
Main method for testing this class.
 o reduceMatrix(double[][])
Reduces a matrix by deleting all zero rows and columns.
 o symmetricalUncertainty(double[][])
Calculates the symmetrical uncertainty for base 2.
 o tauVal(double[][])
Computes Goodman and Kruskal's tau-value for a contingency table.

Constructor Detail

 o ContingencyTables
public ContingencyTables()

Method Detail

 o chiSquared
public static double chiSquared(double matrix[][],
                                boolean yates)
          Returns chi-squared probability for a given matrix.
Parameters:
matrix - the contigency table
yates - is Yates' correction to be used?
Returns:
the chi-squared probability
 o chiVal
public static double chiVal(double matrix[][],
                            boolean useYates)
          Computes chi-squared statistic for a contingency table.
Parameters:
matrix - the contigency table
yates - is Yates' correction to be used?
Returns:
the value of the chi-squared statistic
 o cochransCriterion
public static boolean cochransCriterion(double matrix[][])
          Tests if Cochran's criterion is fullfilled for the given contingency table. Rows and columns with all zeros are not considered relevant.
Parameters:
matrix - the contigency table to be tested
Returns:
true if contingency table is ok, false if not
 o CramersV
public static double CramersV(double matrix[][])
          Computes Cramer's V for a contingency table.
Parameters:
matrix - the contingency table
Returns:
Cramer's V
 o entropy
public static double entropy(double array[])
          Computes the entropy of the given array.
Parameters:
array - the array
Returns:
the entropy
 o entropyConditionedOnColumns
public static double entropyConditionedOnColumns(double matrix[][])
          Computes conditional entropy of the rows given the columns.
Parameters:
matrix - the contingency table
Returns:
the conditional entropy of the rows given the columns
 o entropyConditionedOnRows
public static double entropyConditionedOnRows(double matrix[][])
          Computes conditional entropy of the columns given the rows.
Parameters:
matrix - the contingency table
Returns:
the conditional entropy of the columns given the rows
 o entropyConditionedOnRows
public static double entropyConditionedOnRows(double train[][],
                                              double test[][],
                                              double numClasses)
          Computes conditional entropy of the columns given the rows of the test matrix with respect to the train matrix. Uses a Laplace prior. Does NOT normalize the entropy.
Parameters:
train - the train matrix
test - the test matrix
the - number of symbols for Laplace
Returns:
the entropy
 o entropyOverRows
public static double entropyOverRows(double matrix[][])
          Computes the rows' entropy for the given contingency table.
Parameters:
matrix - the contingency table
Returns:
the rows' entropy
 o entropyOverColumns
public static double entropyOverColumns(double matrix[][])
          Computes the columns' entropy for the given contingency table.
Parameters:
matrix - the contingency table
Returns:
the columns' entropy
 o gainRatio
public static double gainRatio(double matrix[][])
          Computes gain ratio for contingency table (split on rows). Returns Double.MAX_VALUE if the split entropy is 0.
Parameters:
matrix - the contingency table
Returns:
the gain ratio
 o log2MultipleHypergeometric
public static double log2MultipleHypergeometric(double matrix[][])
          Returns negative base 2 logarithm of multiple hypergeometric probability for a contingency table.
Parameters:
matrix - the contingency table
Returns:
the log of the hypergeometric probability of the contingency table
 o reduceMatrix
public static double[][] reduceMatrix(double matrix[][])
          Reduces a matrix by deleting all zero rows and columns.
Parameters:
matrix - the matrix to be reduced
the - matrix with all zero rows and columns deleted
 o symmetricalUncertainty
public static double symmetricalUncertainty(double matrix[][])
          Calculates the symmetrical uncertainty for base 2.
Parameters:
matrix - the contingency table
Returns:
the calculated symmetrical uncertainty
 o tauVal
public static double tauVal(double matrix[][])
          Computes Goodman and Kruskal's tau-value for a contingency table.
Parameters:
matrix - the contingency table
Goodman - and Kruskal's tau-value
 o main
public static void main(java.lang.String ops[])
          Main method for testing this class.

All Packages  Class Hierarchy  This Package  Previous  Next  Index  WEKA's home