Package edu.cmu.tetrad.data

Class CellTableCountSample

java.lang.Object

edu.cmu.tetrad.data.CellTableCountSample

All Implemented Interfaces:

CellTable

public final class CellTableCountSample
extends Object
implements CellTable

Stores a cell count table of arbitrary dimension. Provides methods for incrementing particular cells and for calculating marginals.

This implementation of CellTable uses a MultiDimIntTable to store the cell counts and counts data in the dataset to populate the tables, for each independence question encountered.

Immutable.

Version:

$Id: $Id

Author:

josephramsey

See Also:

• MultiDimIntTable

Constructor Summary

Constructors

Constructor	Description
CellTableCountSample(DataSet dataSet, int[] testIndices)	Constructs a new cell table using the given array for dimensions, initializing all cells in the table to zero.
CellTableCountSample(DataSet dataSet, int[] testIndices, List<Integer> rows)	Constructs a new cell table using the given array for dimensions, initializing all cells in the table to zero.

Method Summary

Modifier and Type	Method	Description
int	calcMargin(int[] coords)	Calculates a marginal sum for the cell table.
int	calcMargin(int[] coords, int[] marginVars)	An alternative way to specify a marginal calculation.
int	getDimension(int varIndex)	Returns the dimensions of the given variable.
int	getValue(int[] coords)	Returns the value of the cell specified by the given coordinates.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

CellTableCountSample

public CellTableCountSample(DataSet dataSet,
 int[] testIndices)

Constructs a new cell table using the given array for dimensions, initializing all cells in the table to zero. This constructor assumes no subsampling.

Parameters:

dataSet - the data set to be used in the table.

testIndices - the indices of the variables to be used in the table.

CellTableCountSample

public CellTableCountSample(DataSet dataSet,
 int[] testIndices,
 List<Integer> rows)

Constructs a new cell table using the given array for dimensions, initializing all cells in the table to zero. The rows of the dataset to use; the default is to use all the rows. This is useful for subsampling.

Parameters:

dataSet - the data set to be used in the table.

testIndices - the indices of the variables to be used in the table.

rows - the rows of the dataset to use; if null, all rows are used.

Method Details

getDimension

public int getDimension(int varIndex)

Returns the dimensions of the given variable.

Specified by:

getDimension in interface CellTable

Parameters:

varIndex - the index of the variable in question.

Returns:

the dimension of the variable.

calcMargin

public int calcMargin(int[] coords)

Calculates a marginal sum for the cell table. The variables over which marginal sums should be taken are indicated by placing "-1's" in the appropriate positions in the coordinate argument. For instance, to find the margin for v0 = 1, v1 = 3, and v3 = 2, where the marginal sum ranges over all values of v2 and v4, the array [1, 3, -1, 2, -1] should be used.

Specified by:

calcMargin in interface CellTable

Parameters:

coords - an array of the sort described above.

Returns:

the marginal sum specified.

calcMargin

public int calcMargin(int[] coords,
 int[] marginVars)

An alternative way to specify a marginal calculation. In this case, coords specifies a particular cell in the table, and varIndices is an array containing the indices of the variables over which the margin sum should be calculated. The sum is over the cell specified by 'coord' and all the cells which differ from that cell in any of the specified coordinates.

Specified by:

calcMargin in interface CellTable

Parameters:

coords - an int[] value

marginVars - an int[] value

Returns:

an int value

getValue

public int getValue(int[] coords)

Returns the value of the cell specified by the given coordinates.

Specified by:

getValue in interface CellTable

Parameters:

coords - the coordinates of the cell.

Returns:

the value of the cell.