Represents a single factor or set of factors whose parameters should be estimated. More...

#include <dai/emalg.h>

Public Types
typedef size_t	FactorIndex
	Convenience label for an index of a factor in a FactorGraph. More...

typedef std::map< FactorIndex, std::vector< Var > >	FactorOrientations
	Convenience label for a grouping of factor orientations. More...

Public Member Functions
	SharedParameters (const FactorOrientations &varorders, ParameterEstimation *estimation, bool ownPE=false)
	Constructor. More...

	SharedParameters (std::istream &is, const FactorGraph &fg)
	Construct a SharedParameters object from an input stream is and a factor graph fg. More...

	SharedParameters (const SharedParameters &sp)
	Copy constructor. More...

	~SharedParameters ()
	Destructor. More...

void	collectExpectations (InfAlg &alg)
	Collect the expected values (beliefs) according to alg. More...

const Prob &	currentExpectations () const
	Return the current accumulated expectations. More...

ParameterEstimation &	getPEst () const

void	setParameters (FactorGraph &fg)
	Estimate and set the shared parameters. More...

const FactorOrientations &	getFactorOrientations () const
	Return a reference to the vector of factor orientations. More...

void	clear ()
	Reset the current expectations. More...

Private Member Functions
void	setPermsAndVarSetsFromVarOrders ()
	Initializes _varsets and _perms from _varorders and checks whether their state spaces correspond with _estimation.probSize() More...

Static Private Member Functions
static Permute	calculatePermutation (const std::vector< Var > &varOrder, VarSet &outVS)
	Calculates the permutation that permutes the canonical ordering into the desired ordering. More...

Private Attributes
std::map< FactorIndex, VarSet >	_varsets
	Maps factor indices to the corresponding VarSets. More...

std::map< FactorIndex, Permute >	_perms
	Maps factor indices to the corresponding Permute objects that permute the canonical ordering into the desired ordering. More...

FactorOrientations	_varorders
	Maps factor indices to the corresponding desired variable orderings. More...

ParameterEstimation *	_estimation
	Parameter estimation method to be used. More...

bool	_ownEstimation
	Indicates whether `*this` gets ownership of _estimation. More...

Prob *	_expectations
	The accumulated expectations. More...

Detailed Description

Represents a single factor or set of factors whose parameters should be estimated.

To ensure that parameters can be shared between different factors during EM learning, each factor's values are reordered to match a desired variable ordering. The ordering of the variables in a factor may therefore differ from the canonical ordering used in libDAI. The SharedParameters class combines one or more factors (together with the specified orderings of the variables) with a ParameterEstimation object, taking care of the necessary permutations of the factor entries / parameters.

Author: Charles Vaske

Member Typedef Documentation

typedef size_t dai::SharedParameters::FactorIndex

Convenience label for an index of a factor in a FactorGraph.

typedef std::map<FactorIndex, std::vector<Var> > dai::SharedParameters::FactorOrientations

Convenience label for a grouping of factor orientations.

Constructor & Destructor Documentation

dai::SharedParameters::SharedParameters	(	const FactorOrientations &	varorders,
		ParameterEstimation *	estimation,
		bool	ownPE = `false`
	)

Constructor.

Parameters

varorders	all the factor orientations for this parameter
estimation	a pointer to the parameter estimation method
ownPE	whether the constructed object gets ownership of estimation

dai::SharedParameters::SharedParameters	(	std::istream &	is,
		const FactorGraph &	fg
	)

Construct a SharedParameters object from an input stream is and a factor graph fg.

See also: Shared parameters block format

Exceptions

INVALID_EMALG_FILE if the input stream is not valid

dai::SharedParameters::SharedParameters ( const SharedParameters & sp )

inline

Copy constructor.

dai::SharedParameters::~SharedParameters ( )

inline

Destructor.

Member Function Documentation

Permute dai::SharedParameters::calculatePermutation	(	const std::vector< Var > &	varOrder,
		VarSet &	outVS
	)

staticprivate

Calculates the permutation that permutes the canonical ordering into the desired ordering.

Parameters

varOrder	Desired ordering of variables
outVS	Contains variables in varOrder represented as a VarSet

Returns: Permute object for permuting variables in varOrder from the canonical libDAI ordering into the desired ordering

void dai::SharedParameters::setPermsAndVarSetsFromVarOrders ( )

private

Initializes _varsets and _perms from _varorders and checks whether their state spaces correspond with _estimation.probSize()

void dai::SharedParameters::collectExpectations ( InfAlg & alg )

Collect the expected values (beliefs) according to alg.

For each of the relevant factors (that shares the parameters we are interested in), the corresponding belief according to alg is obtained and its entries are permuted such that their ordering corresponds with the shared parameters that we are estimating.

const Prob& dai::SharedParameters::currentExpectations ( ) const

inline

Return the current accumulated expectations.

void dai::SharedParameters::setParameters ( FactorGraph & fg )

Estimate and set the shared parameters.

Based on the expectation statistics collected so far, the shared parameters are estimated using the parameter estimation subclass method estimate(). Then, each of the relevant factors in fg (that shares the parameters we are interested in) is set according to those parameters (permuting the parameters accordingly).

const FactorOrientations& dai::SharedParameters::getFactorOrientations ( ) const

inline

Return a reference to the vector of factor orientations.

This is necessary for determing which variables were used to estimate parameters, and analysis of expectations after an Estimation step has been performed.

void dai::SharedParameters::clear ( )

inline

Reset the current expectations.

Member Data Documentation

std::map<FactorIndex, VarSet> dai::SharedParameters::_varsets

private

Maps factor indices to the corresponding VarSets.

std::map<FactorIndex, Permute> dai::SharedParameters::_perms

private

Maps factor indices to the corresponding Permute objects that permute the canonical ordering into the desired ordering.

FactorOrientations dai::SharedParameters::_varorders

private

Maps factor indices to the corresponding desired variable orderings.

ParameterEstimation* dai::SharedParameters::_estimation

private

Parameter estimation method to be used.

bool dai::SharedParameters::_ownEstimation

private

Indicates whether *this gets ownership of _estimation.

Prob* dai::SharedParameters::_expectations

private

The accumulated expectations.

The documentation for this class was generated from the following files:

include/dai/emalg.h
src/emalg.cpp

Public Types

Public Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation