Package cc.mallet.fst.semi_supervised.constraints

Class SelfTransitionGEConstraint

java.lang.Object

cc.mallet.fst.semi_supervised.constraints.SelfTransitionGEConstraint

All Implemented Interfaces:

GEConstraint

public class SelfTransitionGEConstraint
extends java.lang.Object
implements GEConstraint

GE Constraint on the probability of self-transitions in the FST.

Author:

Gregory Druck

Constructor Summary

Constructors

Constructor	Description
SelfTransitionGEConstraint(double selfTransProb, double weight)

Method Summary

Modifier and Type	Method	Description
void	computeExpectations(java.util.ArrayList<SumLattice> lattices)	Compute expectations using cached lattices.
GEConstraint	copy()	This is used in multi-threading.
double	getCompositeConstraintFeatureValue(FeatureVector fv, int ip, int si1, int si2)	Computes the composite constraint feature value (over all constraint features) for FeatureVector fv and a transition from state li1 to li2.
double	getValue()	Returns the total constraint value.
boolean	isOneStateConstraint()
void	preProcess(FeatureVector fv)	Gives the constraint the option to do some caching using only the FeatureVector.
java.util.BitSet	preProcess(InstanceList data)
void	setStateLabelMap(StateLabelMap map)	Sets that map between the state indices and label indices.
void	zeroExpectations()	Zero expectation values.

Methods inherited from class java.lang.Object

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

Constructor Detail

SelfTransitionGEConstraint

public SelfTransitionGEConstraint(double selfTransProb,
                                  double weight)

Parameters:

selfTransProb - Probability of self-transition

weight - Weight of this constraint in the objective function

Method Detail

copy

public GEConstraint copy()

Description copied from interface: GEConstraint

This is used in multi-threading.

Specified by:

copy in interface GEConstraint

Returns:

A copy of the GEConstraint.

isOneStateConstraint

public boolean isOneStateConstraint()

Specified by:

isOneStateConstraint in interface GEConstraint

Returns:

true if constraint feature only considers one state

setStateLabelMap

public void setStateLabelMap(StateLabelMap map)

Description copied from interface: GEConstraint

Sets that map between the state indices and label indices.

Specified by:

setStateLabelMap in interface GEConstraint

Parameters:

map - StateLabelMap

preProcess

public void preProcess(FeatureVector fv)

Description copied from interface: GEConstraint

Gives the constraint the option to do some caching using only the FeatureVector. For example, the constrained input features could be cached.

Specified by:

preProcess in interface GEConstraint

Parameters:

fv - FeatureVector input

preProcess

public java.util.BitSet preProcess(InstanceList data)

Specified by:

preProcess in interface GEConstraint

Parameters:

data - Unlabeled data

Returns:

Returns a bitset of the size of the data, with the bit set if a constraint feature fires in that instance.

getCompositeConstraintFeatureValue

public double getCompositeConstraintFeatureValue(FeatureVector fv,
                                                 int ip,
                                                 int si1,
                                                 int si2)

Description copied from interface: GEConstraint

Computes the composite constraint feature value (over all constraint features) for FeatureVector fv and a transition from state li1 to li2.

Specified by:

getCompositeConstraintFeatureValue in interface GEConstraint

Parameters:

fv - FeatureVector on transition

ip - Position of input in sequence

si1 - Source state index for transition

si2 - Destination state index for transition

Returns:

Constraint feature value

getValue

public double getValue()

Description copied from interface: GEConstraint

Returns the total constraint value.

Specified by:

getValue in interface GEConstraint

Returns:

Constraint value

zeroExpectations

public void zeroExpectations()

Description copied from interface: GEConstraint

Zero expectation values. Called before re-computing gradient.

Specified by:

zeroExpectations in interface GEConstraint

computeExpectations

public void computeExpectations(java.util.ArrayList<SumLattice> lattices)

Description copied from interface: GEConstraint

Compute expectations using cached lattices.

Specified by:

computeExpectations in interface GEConstraint

Parameters:

lattices - Cached SumLattices