pt.tumba.ngram.bayes
Class DiscreteFunction

java.lang.Object
  pt.tumba.ngram.bayes.DiscreteFunction

All Implemented Interfaces:

java.io.Serializable

Direct Known Subclasses:

ProbabilityFunction

public class DiscreteFunction
extends java.lang.Object
implements java.io.Serializable

See Also:

Serialized Form

Field Summary

protected double[]	values
protected DiscreteVariable[]	variables

Constructor Summary

DiscreteFunction()
Default constructor for a DiscreteFunction.

DiscreteFunction(DiscreteVariable[] pvs, double[] v)
Simple constructor for DiscreteFunction.

DiscreteFunction(int n_vb, int n_vl)
Simple constructor for DiscreteFunction.

Method Summary

double	evaluate(DiscreteVariable[] pvs, int[] value_indexes) Evaluate a function given a (possibly partial) instantiation of variables through the indexes.
int	get_index(int ind) Get a DiscreteVariable object with a particular index.
int[]	get_indexes() Get an array with all the indexes of the DiscreteVariable objects in the current DiscreteFunction.
int	get_position_from_indexes(DiscreteVariable[] pvs, int[] variable_indexes) Get position in a function from a (possibly partial) instantiation of variables through the indexes.
double	get_value(int index) Get a value of the current DiscreteFunction given the position of the value in the array of values.
double[]	get_values() Get all values of the current DiscreteFunction.
DiscreteVariable	get_variable(int index) Get a variable in the current DiscreteFunction.
DiscreteVariable[]	get_variables() Get the variables in the current DiscreteFunction.
boolean	memberOf(int index) Check whether an index is present in the function.
DiscreteFunction	multiply(DiscreteVariable[] dvs, DiscreteFunction mult) Multiply two DiscreteFunction objects.
void	normalize_first() Normalize a function (in-place) assuming that it is a conditional distribution for the first variable
void	normalize() Normalize a function (in-place).
int	number_values() Return the number of values in the current DiscreteFunction.
int	number_variables() Return the number of DiscreteVariable objects in the current DiscreteFunction.
void	print() Print method for DiscreteFunction.
void	print(java.io.PrintStream out) Print method for DiscreteFunction into a PrintStream.
(package private) boolean	same_variables(DiscreteFunction df)
void	set_value(int index, double v) Set a value in the current DiscreteFunction given its position in the array of values.
void	set_values(double[] vs) Set the values in the DiscreteFunction.
void	set_variable(int index, DiscreteVariable dv) Set a DiscreteVariable in the current DiscreteFunction given its position in the array of values.
DiscreteFunction	sum_out(DiscreteVariable[] dvs, boolean[] markers) Sum out some variables in the function.

Methods inherited from class java.lang.Object

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

Field Detail

variables

protected DiscreteVariable[] variables

values

protected double[] values

Constructor Detail

DiscreteFunction

public DiscreteFunction()

Default constructor for a DiscreteFunction.

DiscreteFunction

public DiscreteFunction(int n_vb,
                        int n_vl)

Simple constructor for DiscreteFunction.

Parameters:

n_vb - Number of variables in the function.

n_vl - Number of values in the function.

DiscreteFunction

public DiscreteFunction(DiscreteVariable[] pvs,
                        double[] v)

Simple constructor for DiscreteFunction.

Parameters:

pvs - An array of ProbabilityVariable objects.

v - An array of values for the function.

Method Detail

memberOf

public boolean memberOf(int index)

Check whether an index is present in the function.

same_variables

boolean same_variables(DiscreteFunction df)

evaluate

public double evaluate(DiscreteVariable[] pvs,
                       int[] value_indexes)

Evaluate a function given a (possibly partial) instantiation of variables through the indexes. Indexes indicate which variables are present in the function to be evaluated, assuming an array of DiscreteVariable objects is present.

Parameters:

pvs - The array of DiscreteVariable objects that is used to compute the position indicated by the markers.

value_indexes - The markers.

get_position_from_indexes

public int get_position_from_indexes(DiscreteVariable[] pvs,
                                     int[] variable_indexes)

Get position in a function from a (possibly partial) instantiation of variables through the indexes.

sum_out

public DiscreteFunction sum_out(DiscreteVariable[] dvs,
                                boolean[] markers)

Sum out some variables in the function.

Parameters:

markers - A boolean vector indicating which variables are to be summed out. If markers[i] is true, then the ith variable is to be summed out; if markers[i] is false, the ith variable is not to be summed out.

multiply

public DiscreteFunction multiply(DiscreteVariable[] dvs,
                                 DiscreteFunction mult)

Multiply two DiscreteFunction objects.

normalize

public void normalize()

Normalize a function (in-place).

normalize_first

public void normalize_first()

Normalize a function (in-place) assuming that it is a conditional distribution for the first variable

print

public void print()

Print method for DiscreteFunction.

print

public void print(java.io.PrintStream out)

Print method for DiscreteFunction into a PrintStream.

number_variables

public int number_variables()

Return the number of DiscreteVariable objects in the current DiscreteFunction.

number_values

public int number_values()

Return the number of values in the current DiscreteFunction.

get_variables

public DiscreteVariable[] get_variables()

Get the variables in the current DiscreteFunction.

get_variable

public DiscreteVariable get_variable(int index)

Get a variable in the current DiscreteFunction.

Parameters:

index - Position of the variable to be returned in the array of DiscreteVariable objects.

get_indexes

public int[] get_indexes()

Get an array with all the indexes of the DiscreteVariable objects in the current DiscreteFunction.

get_index

public int get_index(int ind)

Get a DiscreteVariable object with a particular index.

Parameters:

ind - Index of the desired DiscreteVariable.

get_values

public double[] get_values()

Get all values of the current DiscreteFunction.

get_value

public double get_value(int index)

Get a value of the current DiscreteFunction given the position of the value in the array of values.

set_value

public void set_value(int index,
                      double v)

Set a value in the current DiscreteFunction given its position in the array of values.

Parameters:

index - The position of the value.

v - The new value.

set_values

public void set_values(double[] vs)

Set the values in the DiscreteFunction.

set_variable

public void set_variable(int index,
                         DiscreteVariable dv)

Set a DiscreteVariable in the current DiscreteFunction given its position in the array of values.

Parameters:

index - The position of the value.

pv - The new DiscreteVariable.