Detailed Description

Implementation of a discrete-conditioned hybrid factor.

Implements a joint discrete-continuous factor where the discrete variable serves to "select" a component corresponding to a GaussianFactor.

Represents the underlying hybrid Gaussian components as a Decision Tree, where the set of discrete variables indexes to the continuous gaussian distribution.

In factor graphs the error function typically returns 0.5*|A*x - b|^2, i.e., the negative log-likelihood for a Gaussian noise model. In hybrid factor graphs we allow adding an arbitrary scalar dependent on the discrete assignment. For example, adding a 70/30 mode probability is supported by providing the scalars $-log(.7)$ and $-log(.3)$. Note that adding a common constant will not make any difference in the optimization, so $-log(70)$ and $-log(30)$ work just as well.

Inheritance diagram for gtsam::HybridGaussianFactor:

Public Member Functions
Constructors
	HybridGaussianFactor ()=default
	Default constructor, mainly for serialization.
	HybridGaussianFactor (const DiscreteKey &discreteKey, const std::vector< GaussianFactor::shared_ptr > &factors)
	Construct a new HybridGaussianFactor on a single discrete key, providing the factors for each mode m as a vector of factors ϕ_m(x).
	HybridGaussianFactor (const DiscreteKey &discreteKey, const std::vector< GaussianFactorValuePair > &factorPairs)
	Construct a new HybridGaussianFactor on a single discrete key, including a scalar error value for each mode m.
	HybridGaussianFactor (const DiscreteKeys &discreteKeys, const FactorValuePairs &factorPairs)
	Construct a new HybridGaussianFactor on a several discrete keys M, including a scalar error value for each assignment m.
Testable
bool	equals (const HybridFactor &lf, double tol=1e-9) const override
	equals
void	print (const std::string &s="", const KeyFormatter &formatter=DefaultKeyFormatter) const override
	print
Standard API
GaussianFactorValuePair	operator() (const DiscreteValues &assignment) const
	Get factor at a given discrete assignment.
AlgebraicDecisionTree< Key >	errorTree (const VectorValues &continuousValues) const override
	Compute error of the HybridGaussianFactor as a tree.
double	error (const HybridValues &hybridValues) const override
	Compute the log-likelihood, including the log-normalizing constant.
const FactorValuePairs &	factors () const
	Getter for GaussianFactor decision tree.
virtual HybridGaussianProductFactor	asProductFactor () const
	Helper function to return factors and functional to create a DecisionTree of Gaussian Factor Graphs.
std::shared_ptr< Factor >	restrict (const DiscreteValues &discreteValues) const override
	Restrict the factor to the given discrete values.
Public Member Functions inherited from gtsam::HybridFactor
	HybridFactor ()=default
	Default constructor creates empty factor.
	HybridFactor (const KeyVector &keys)
	Construct hybrid factor from continuous keys.
	HybridFactor (const DiscreteKeys &discreteKeys)
	Construct hybrid factor from discrete keys.
	HybridFactor (const KeyVector &continuousKeys, const DiscreteKeys &discreteKeys)
	Construct a new Hybrid Factor object.
bool	isDiscrete () const
	True if this is a factor of discrete variables only.
bool	isContinuous () const
	True if this is a factor of continuous variables only.
bool	isHybrid () const
	True is this is a Discrete-Continuous factor.
size_t	nrContinuous () const
	Return the number of continuous variables in this factor.
const DiscreteKeys &	discreteKeys () const
	Return the discrete keys for this factor.
const KeyVector &	continuousKeys () const
	Return only the continuous keys for this factor.
Public Member Functions inherited from gtsam::Factor
virtual	~Factor ()=default
	Default destructor.
bool	empty () const
	Whether the factor is empty (involves zero variables).
Key	front () const
	First key.
Key	back () const
	Last key.
const_iterator	find (Key key) const
	find
const KeyVector &	keys () const
	Access the factor's involved variable keys.
const_iterator	begin () const
	Iterator at beginning of involved variable keys.
const_iterator	end () const
	Iterator at end of involved variable keys.
size_t	size () const
virtual void	printKeys (const std::string &s="Factor", const KeyFormatter &formatter=DefaultKeyFormatter) const
	print only keys
bool	equals (const This &other, double tol=1e-9) const
	check equality
KeyVector &	keys ()
iterator	begin ()
	Iterator at beginning of involved variable keys.
iterator	end ()
	Iterator at end of involved variable keys.

Public Types
using	Base = HybridFactor
using	This = HybridGaussianFactor
using	shared_ptr = std::shared_ptr<This>
using	sharedFactor = std::shared_ptr<GaussianFactor>
using	FactorValuePairs = DecisionTree<Key, GaussianFactorValuePair>
	typedef for Decision Tree of Gaussian factors and arbitrary value.
Public Types inherited from gtsam::HybridFactor
enum class	Category { None , Discrete , Continuous , Hybrid }
	Enum to help with categorizing hybrid factors.
typedef HybridFactor	This
	This class.
typedef std::shared_ptr< HybridFactor >	shared_ptr
	shared_ptr to this class
typedef Factor	Base
	Our base class.
Public Types inherited from gtsam::Factor
typedef KeyVector::iterator	iterator
	Iterator over keys.
typedef KeyVector::const_iterator	const_iterator
	Const iterator over keys.

Additional Inherited Members
	Factor ()
	Default constructor for I/O.
template<typename CONTAINER>
	Factor (const CONTAINER &keys)
	Construct factor from container of keys.
template<typename ITERATOR>
	Factor (ITERATOR first, ITERATOR last)
	Construct factor from iterator keys.
template<typename CONTAINER>
static Factor	FromKeys (const CONTAINER &keys)
	Construct factor from container of keys.
template<typename ITERATOR>
static Factor	FromIterators (ITERATOR first, ITERATOR last)
	Construct factor from iterator keys.
Protected Attributes inherited from gtsam::HybridFactor
DiscreteKeys	discreteKeys_
KeyVector	continuousKeys_
	Record continuous keys for book-keeping.
Protected Attributes inherited from gtsam::Factor
KeyVector	keys_
	The keys involved in this factor.

Constructor & Destructor Documentation

◆ HybridGaussianFactor() [1/3]

gtsam::HybridGaussianFactor::HybridGaussianFactor	(	const DiscreteKey &	discreteKey,
		const std::vector< GaussianFactor::shared_ptr > &	factors )

Construct a new HybridGaussianFactor on a single discrete key, providing the factors for each mode m as a vector of factors ϕ_m(x).

The value ϕ(x,m) for the factor is simply ϕ_m(x).

Parameters

discreteKey	The discrete key for the "mode", indexing components.
factors	Vector of gaussian factors, one for each mode.

◆ HybridGaussianFactor() [2/3]

gtsam::HybridGaussianFactor::HybridGaussianFactor	(	const DiscreteKey &	discreteKey,
		const std::vector< GaussianFactorValuePair > &	factorPairs )

Construct a new HybridGaussianFactor on a single discrete key, including a scalar error value for each mode m.

The factors and scalars are provided as a vector of pairs (ϕ_m(x), E_m). The value ϕ(x,m) for the factor is now ϕ_m(x) + E_m.

Parameters

discreteKey	The discrete key for the "mode", indexing components.
factorPairs	Vector of gaussian factor-scalar pairs, one per mode.

◆ HybridGaussianFactor() [3/3]

gtsam::HybridGaussianFactor::HybridGaussianFactor	(	const DiscreteKeys &	discreteKeys,
		const FactorValuePairs &	factorPairs )

Construct a new HybridGaussianFactor on a several discrete keys M, including a scalar error value for each assignment m.

The factors and scalars are provided as a DecisionTree<Key> of pairs (ϕ_M(x), E_M). The value ϕ(x,M) for the factor is again ϕ_m(x) + E_m.

Parameters

discreteKeys	Discrete variables and their cardinalities.
factorPairs	The decision tree of Gaussian factor/scalar pairs.

Member Function Documentation

◆ asProductFactor()

HybridGaussianProductFactor gtsam::HybridGaussianFactor::asProductFactor ( ) const

virtual

Helper function to return factors and functional to create a DecisionTree of Gaussian Factor Graphs.

Returns: HybridGaussianProductFactor

◆ equals()

bool gtsam::HybridGaussianFactor::equals	(	const HybridFactor &	lf,
		double	tol = 1e-9 ) const

overridevirtual

equals

Reimplemented from gtsam::HybridFactor.

◆ error()

double gtsam::HybridGaussianFactor::error ( const HybridValues & hybridValues ) const

overridevirtual

Compute the log-likelihood, including the log-normalizing constant.

Returns: double

Reimplemented from gtsam::Factor.

◆ errorTree()

AlgebraicDecisionTree< Key > gtsam::HybridGaussianFactor::errorTree ( const VectorValues & continuousValues ) const

overridevirtual

Compute error of the HybridGaussianFactor as a tree.

Parameters

continuousValues The continuous VectorValues.

Returns: AlgebraicDecisionTree<Key> A decision tree with the same keys as the factors involved, and leaf values as the error.

Implements gtsam::HybridFactor.

◆ print()

void gtsam::HybridGaussianFactor::print	(	const std::string &	s = "",
		const KeyFormatter &	formatter = DefaultKeyFormatter ) const

overridevirtual

print

Reimplemented from gtsam::HybridFactor.

◆ restrict()

std::shared_ptr< Factor > gtsam::HybridGaussianFactor::restrict ( const DiscreteValues & discreteValues ) const

overridevirtual

Restrict the factor to the given discrete values.

Implements gtsam::HybridFactor.

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

/tmp/gtsam-4.3.0-doxygen.rsXPUS/source/gtsam/hybrid/HybridGaussianFactor.h
/tmp/gtsam-4.3.0-doxygen.rsXPUS/source/gtsam/hybrid/HybridGaussianFactor.cpp

Detailed Description

Public Member Functions

Public Types

Additional Inherited Members

Constructor & Destructor Documentation

◆ HybridGaussianFactor() [1/3]

◆ HybridGaussianFactor() [2/3]

◆ HybridGaussianFactor() [3/3]

Member Function Documentation

◆ asProductFactor()

◆ equals()

◆ error()

◆ errorTree()

◆ print()

◆ restrict()