Detailed Description

As a type-erased variant of:

The reason why this is important is that Conditional<T> is a CRTP class. CRTP is static polymorphism such that all CRTP classes, while bearing the same name, are different classes not sharing a vtable. This prevents them from being contained in any container, and thus it is impossible to dynamically cast between them. A better option, as illustrated here, is treating them as an implementation detail - such that the hybrid mechanism does not know what is inside the HybridConditional. This prevents us from having diamond inheritances, and neutralized the need to change other components of GTSAM to make hybrid elimination work.

A great reference to the type-erasure pattern is Eduardo Madrid's CppCon talk (https://www.youtube.com/watch?v=s082Qmd_nHs).

Inheritance diagram for gtsam::HybridConditional:

Public Member Functions
Standard Constructors
	HybridConditional ()=default
	Default constructor needed for serialization.
	HybridConditional (const KeyVector &continuousKeys, const DiscreteKeys &discreteKeys, size_t nFrontals)
	Construct a new Hybrid Conditional object.
	HybridConditional (const KeyVector &continuousFrontals, const DiscreteKeys &discreteFrontals, const KeyVector &continuousParents, const DiscreteKeys &discreteParents)
	Construct a new Hybrid Conditional object.
	HybridConditional (const std::shared_ptr< GaussianConditional > &continuousConditional)
	Construct a new Hybrid Conditional object.
	HybridConditional (const std::shared_ptr< DiscreteConditional > &discreteConditional)
	Construct a new Hybrid Conditional object.
	HybridConditional (const std::shared_ptr< HybridGaussianConditional > &hybridGaussianCond)
	Construct a new Hybrid Conditional object.
Testable
void	print (const std::string &s="Hybrid Conditional: ", const KeyFormatter &formatter=DefaultKeyFormatter) const override
	GTSAM-style print.
bool	equals (const HybridFactor &other, double tol=1e-9) const override
	GTSAM-style equals.
Standard Interface
HybridGaussianConditional::shared_ptr	asHybrid () const
	Return HybridConditional as a HybridGaussianConditional.
GaussianConditional::shared_ptr	asGaussian () const
	Return HybridConditional as a GaussianConditional.
template<typename T = DiscreteConditional>
T::shared_ptr	asDiscrete () const
	Return conditional as a DiscreteConditional or specified type T.
std::shared_ptr< Factor >	inner () const
	Get the type-erased pointer to the inner type.
double	error (const HybridValues &hybridValues) const override
	Return the error of the underlying conditional.
AlgebraicDecisionTree< Key >	errorTree (const VectorValues &continuousValues) const override
	Compute error of the HybridConditional as a tree.
double	logProbability (const HybridValues &values) const override
	Return the log-probability (or density) of the underlying conditional.
double	negLogConstant () const override
	Return the negative log of the normalization constant.
double	evaluate (const HybridValues &values) const override
	Return the probability (or density) of the underlying conditional.
bool	frontalsIn (const VectorValues &measurements) const
	Check if VectorValues measurements contains all frontal keys.
std::shared_ptr< Factor >	restrict (const DiscreteValues &assignment) const override
	Return a HybridConditional by choosing branches based on 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.
void	print (const std::string &s="HybridFactor\n", const KeyFormatter &formatter=DefaultKeyFormatter) const override
	print
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 Member Functions inherited from gtsam::Conditional< HybridFactor, HybridConditional >
void	print (const std::string &s="Conditional", const KeyFormatter &formatter=DefaultKeyFormatter) const
	print with optional formatter
bool	equals (const This &c, double tol=1e-9) const
	check equality
size_t	nrFrontals () const
	return the number of frontals
size_t	nrParents () const
	return the number of parents
Key	firstFrontalKey () const
	Convenience function to get the first frontal key.
Frontals	frontals () const
	return a view of the frontal keys
Parents	parents () const
	return a view of the parent keys
double	operator() (const HybridValues &x) const
	Evaluate probability density, sugar.
HybridFactor::const_iterator	beginFrontals () const
	Iterator pointing to first frontal key.
HybridFactor::const_iterator	endFrontals () const
	Iterator pointing past the last frontal key.
HybridFactor::const_iterator	beginParents () const
	Iterator pointing to the first parent key.
HybridFactor::const_iterator	endParents () const
	Iterator pointing past the last parent key.

Public Types
typedef HybridConditional	This
	Typedef to this class.
typedef std::shared_ptr< This >	shared_ptr
	shared_ptr to this class
typedef HybridFactor	BaseFactor
	Typedef to our factor base class.
typedef Conditional< BaseFactor, This >	BaseConditional
	Typedef to our conditional base class.
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.
Public Types inherited from gtsam::Conditional< HybridFactor, HybridConditional >
typedef std::pair< typename HybridFactor::const_iterator, typename HybridFactor::const_iterator >	ConstFactorRange
	A mini implementation of an iterator range, to share const views of frontals and parents.
typedef ConstFactorRangeIterator	Frontals
	View of the frontal keys (call frontals()).
typedef ConstFactorRangeIterator	Parents
	View of the separator keys (call parents()).

Protected Attributes
std::shared_ptr< Factor >	inner_
	Type-erased pointer to the inner type.
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.
Protected Attributes inherited from gtsam::Conditional< HybridFactor, HybridConditional >
size_t	nrFrontals_
	The first nrFrontal variables are frontal and the rest are parents.

Additional Inherited Members
static bool	CheckInvariants (const HybridConditional &conditional, const VALUES &x)
	Check invariants of this conditional, given the values x.
	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.
Protected Member Functions inherited from gtsam::Conditional< HybridFactor, HybridConditional >
	Conditional ()
	Empty Constructor to make serialization possible.
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.