cc.mallet.grmm.types
Class CPT

java.lang.Object
  cc.mallet.grmm.types.CPT

All Implemented Interfaces:

DiscreteFactor, Factor, java.io.Serializable, java.lang.Cloneable

public class CPT
extends java.lang.Object
implements DiscreteFactor

$Id: CPT.java,v 1.1 2007/10/22 21:37:44 mccallum Exp $

See Also:

Serialized Form

Constructor Summary

CPT(DiscreteFactor subFactor, Variable child)

Method Summary

boolean	almostEquals(Factor p) Returns whether this is almost equal to another potential.
boolean	almostEquals(Factor p, double epsilon)
int	argmax() Returns the assignment that maximizes this potential.
AssignmentIterator	assignmentIterator() Returns an iterator over all Assignmentss to this potential.
AbstractTableFactor	asTable()
boolean	containsVar(Variable var) Returns whether the potential is over the given variable.
void	divideBy(Factor pot) Computes this /= pot
java.lang.String	dumpToString()
Factor	duplicate()
double	entropy() Returns the expected log factor value, i.e., sum_x factor.value(x) * Math.log (factor.value (x)) where the summation is taken over all passible assignments.
void	exponentiate(double power)
Factor	extractMax(java.util.Collection vars) Returns a potential phi over the given variables obtained by taking phi (x) = max_[all v that contain x] this.prob (x)
Factor	extractMax(Variable var) Returns a potential phi over the given variables obtained by taking phi (x) = max_[all v that contain x] this.prob (x)
Factor	extractMax(Variable[] vars) Returns a potential phi over the given variables obtained by taking phi (x) = max_[all v that contain x] this.prob (x)
Variable	getChild()
VarSet	getParents()
Variable	getVariable(int i)
int	indexAtLocation(int loc)
boolean	isNaN()
double	logValue(Assignment assn)
double	logValue(AssignmentIterator it)
double	logValue(int loc)
Factor	marginalize(java.util.Collection vars) Returns the marginal of this distribution over the given variables.
Factor	marginalize(Variable var) Returns the marginal of this distribution over one variable.
Factor	marginalize(Variable[] vars) Returns the marginal of this distribution over the given variables.
Factor	marginalizeOut(Variable var) Returns the marginal distribution attained by summing out the given variable.
Factor	marginalizeOut(VarSet varset) Returns the marginal distribution attained by summing out the given set of variables.
Factor	multiply(Factor dist) Returns the elementwise product of this factor with another.
void	multiplyBy(Factor pot) Does this *= pot.
Factor	normalize() Multiplies this potential by a constant such that it sums to 1.
int	numLocations()
java.lang.String	prettyOutputString()
Assignment	sample(Randoms r) Return an assignment sampled from this factor, interpreting it as an unnormalized probability distribution.
int	sampleLocation(Randoms r)
void	setSubFactor(DiscreteFactor subFactor)
int	singleIndex(int[] smallDims)
Factor	slice(Assignment assn)
double	sum() Returns the sum of this potential over all cases.
java.lang.String	toString()
double[]	toValueArray()
double	value(Assignment assn) Returns the value of the local function for a given assignment.
double	value(AssignmentIterator it) Returns the probability of an assignment to these variables.
double	value(int index)
double	valueAtLocation(int loc)
VarSet	varSet() Returns set of variables in this potential.

Methods inherited from class java.lang.Object

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

Constructor Detail

CPT

public CPT(DiscreteFactor subFactor,
           Variable child)

Method Detail

getParents

public VarSet getParents()

getChild

public Variable getChild()

setSubFactor

public void setSubFactor(DiscreteFactor subFactor)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

prettyOutputString

public java.lang.String prettyOutputString()

Specified by:

prettyOutputString in interface Factor

value

public double value(Assignment assn)

Description copied from interface: Factor

Returns the value of the local function for a given assignment. All variables in the potential must be included, but it's okay if the assignment uses variables not in the potential.

Specified by:

value in interface Factor

value

public double value(AssignmentIterator it)

Description copied from interface: Factor

Returns the probability of an assignment to these variables. The assignment used is the curret assignment from the given AssignmentIterator.

This can be used to do things like

         DiscretePotential phi = createMyPtl ();
         for (AssignmentIterator it = phi.assignmentIterator; it.hasNext(); it.advance()) {
           double val = ptl.phi (it);
                 // do something with val
   }
  

This is equivalent to creating an assignment object explicitly using (Assignment) it.next(), but can be much faster.

Specified by:

value in interface Factor

normalize

public Factor normalize()

Description copied from interface: Factor

Multiplies this potential by a constant such that it sums to 1. Destructive; returns this factor.

Specified by:

normalize in interface Factor

marginalize

public Factor marginalize(Variable[] vars)

Description copied from interface: Factor

Returns the marginal of this distribution over the given variables.

Specified by:

marginalize in interface Factor

marginalize

public Factor marginalize(java.util.Collection vars)

Description copied from interface: Factor

Returns the marginal of this distribution over the given variables.

Specified by:

marginalize in interface Factor

marginalize

public Factor marginalize(Variable var)

Description copied from interface: Factor

Returns the marginal of this distribution over one variable.

Specified by:

marginalize in interface Factor

marginalizeOut

public Factor marginalizeOut(Variable var)

Description copied from interface: Factor

Returns the marginal distribution attained by summing out the given variable.

Specified by:

marginalizeOut in interface Factor

extractMax

public Factor extractMax(java.util.Collection vars)

Description copied from interface: Factor

Returns a potential phi over the given variables obtained by taking phi (x) = max_[all v that contain x] this.prob (x)

Specified by:

extractMax in interface Factor

extractMax

public Factor extractMax(Variable var)

Description copied from interface: Factor

Returns a potential phi over the given variables obtained by taking phi (x) = max_[all v that contain x] this.prob (x)

Specified by:

extractMax in interface Factor

extractMax

public Factor extractMax(Variable[] vars)

Description copied from interface: Factor

Returns a potential phi over the given variables obtained by taking phi (x) = max_[all v that contain x] this.prob (x)

Specified by:

extractMax in interface Factor

argmax

public int argmax()

Description copied from interface: Factor

Returns the assignment that maximizes this potential.

Specified by:

argmax in interface Factor

sample

public Assignment sample(Randoms r)

Description copied from interface: Factor

Return an assignment sampled from this factor, interpreting it as an unnormalized probability distribution.

Specified by:

sample in interface Factor

sum

public double sum()

Description copied from interface: Factor

Returns the sum of this potential over all cases.

Specified by:

sum in interface Factor

entropy

public double entropy()

Description copied from interface: Factor

Returns the expected log factor value, i.e., sum_x factor.value(x) * Math.log (factor.value (x)) where the summation is taken over all passible assignments.

Specified by:

entropy in interface Factor

multiply

public Factor multiply(Factor dist)

Description copied from interface: Factor

Returns the elementwise product of this factor with another.

Specified by:

multiply in interface Factor

multiplyBy

public void multiplyBy(Factor pot)

Description copied from interface: Factor

Does this *= pot.

If both potentials are currently in log space, then does addition instead.

Specified by:

multiplyBy in interface Factor

exponentiate

public void exponentiate(double power)

Specified by:

exponentiate in interface Factor

divideBy

public void divideBy(Factor pot)

Description copied from interface: Factor

Computes this /= pot

If both potentials are currently in log space, then does subtraction instead.

Specified by:

divideBy in interface Factor

containsVar

public boolean containsVar(Variable var)

Description copied from interface: Factor

Returns whether the potential is over the given variable.

Specified by:

containsVar in interface Factor

varSet

public VarSet varSet()

Description copied from interface: Factor

Returns set of variables in this potential.

Specified by:

varSet in interface Factor

assignmentIterator

public AssignmentIterator assignmentIterator()

Description copied from interface: Factor

Returns an iterator over all Assignmentss to this potential.

Specified by:

assignmentIterator in interface Factor

almostEquals

public boolean almostEquals(Factor p)

Description copied from interface: Factor

Returns whether this is almost equal to another potential.

Specified by:

almostEquals in interface Factor

almostEquals

public boolean almostEquals(Factor p,
                            double epsilon)

Specified by:

almostEquals in interface Factor

duplicate

public Factor duplicate()

Specified by:

duplicate in interface Factor

isNaN

public boolean isNaN()

Specified by:

isNaN in interface Factor

logValue

public double logValue(AssignmentIterator it)

Specified by:

logValue in interface Factor

logValue

public double logValue(Assignment assn)

Specified by:

logValue in interface Factor

logValue

public double logValue(int loc)

Specified by:

logValue in interface Factor

getVariable

public Variable getVariable(int i)

Specified by:

getVariable in interface Factor

sampleLocation

public int sampleLocation(Randoms r)

Specified by:

sampleLocation in interface DiscreteFactor

value

public double value(int index)

Specified by:

value in interface DiscreteFactor

numLocations

public int numLocations()

Specified by:

numLocations in interface DiscreteFactor

valueAtLocation

public double valueAtLocation(int loc)

Specified by:

valueAtLocation in interface DiscreteFactor

indexAtLocation

public int indexAtLocation(int loc)

Specified by:

indexAtLocation in interface DiscreteFactor

toValueArray

public double[] toValueArray()

Specified by:

toValueArray in interface DiscreteFactor

singleIndex

public int singleIndex(int[] smallDims)

Specified by:

singleIndex in interface DiscreteFactor

dumpToString

public java.lang.String dumpToString()

Specified by:

dumpToString in interface Factor

slice

public Factor slice(Assignment assn)

Specified by:

slice in interface Factor

asTable

public AbstractTableFactor asTable()

Specified by:

asTable in interface Factor

marginalizeOut

public Factor marginalizeOut(VarSet varset)

Description copied from interface: Factor

Returns the marginal distribution attained by summing out the given set of variables.

Specified by:

marginalizeOut in interface Factor