Detailed Description

template<typename FactorType, int ErrorDim>
class gtsam::BatchFactor< FactorType, ErrorDim >

BatchFactor is a NonlinearFactor that wraps a collection of identical factors.

It linearizes them all at once into a single JacobianFactor.

This is useful for optimizing Structure-from-Motion (SfM) and SLAM graphs where we have many factors of the same type (e.g., projection factors) that can be grouped together to reduce overhead.

Usage Example:

// Assume we have GenericProjectionFactor<Pose3, Point3> using ProjectionFactor = GenericProjectionFactor<Pose3, Point3>;

// Create a batch factor std::vector<Key> poses = {Symbol('x', 1)}; std::vector<Key> points; std::vector<Point2> measurements; for (int i = 0; i < 100; ++i) { points.push_back(Symbol('l', i)); measurements.push_back(Point2(10, 10)); // Dummy measurement }

auto noise = noiseModel::Isotropic::Sigma(2, 1.0);

// Construct using the helper (1 camera, 100 points) auto batch = std::make_shared<BatchFactor<ProjectionFactor, 2>>( poses, points, measurements, noise);

// Add to graph NonlinearFactorGraph graph; graph.add(batch);

// Optimize as usual LevenbergMarquardtOptimizer optimizer(graph, initial_values); Values result = optimizer.optimize();

Template Parameters

FactorType	The type of the individual factors
ErrorDim	The dimension of the error vector for a single factor

Inheritance diagram for gtsam::BatchFactor< FactorType, ErrorDim >:

Public Member Functions
Constructors
	BatchFactor ()=default
	Default constructor.
const FactorVector &	factors () const
	Return the child factors represented by this batch.
size_t	numFactors () const
	Return the number of child factors represented by this batch.
	BatchFactor (std::vector< FactorType, Allocator > &&factors)
	Constructor from a vector of factors (moves the vector).
	BatchFactor (const std::vector< FactorType, Allocator > &factors)
	Constructor from a vector of factors (copies the vector).
	BatchFactor (const std::vector< FactorType > &factors)
	Constructor from a standard vector of factors (copies the vector).
	BatchFactor (std::vector< FactorType > &&factors)
	Constructor from a standard vector of factors (moves elements).
template<typename Measurement, typename... Args>
	BatchFactor (Key key1, const std::map< Key, Measurement > &measurements, const SharedNoiseModel &model, Args &&... args)
	Map-based Constructor (Varying Key2).
template<typename Measurement, typename... Args>
	BatchFactor (const std::map< Key, Measurement > &measurements, Key key2, const SharedNoiseModel &model, Args &&... args)
	Map-based Constructor (Varying Key1).
Testable
void	print (const std::string &s="", const KeyFormatter &keyFormatter=DefaultKeyFormatter) const override
	Print the BatchFactor.
bool	equals (const NonlinearFactor &f, double tol=1e-9) const override
	Check equality with another factor.
Standard Interface
double	error (const Values &c) const override
	Calculate the error of the factor.
size_t	dim () const override
	Get the dimension of the factor (number of rows on linearization).
void	setUseHessianFactor (bool flag)
std::shared_ptr< GaussianFactor >	linearize (const Values &values) const override
	Linearize to a single JacobianFactor.
template<size_t... Is>
void	collectKeys (const FactorType &f, std::index_sequence< Is... >)
	Helper to collect keys and dimensions using fold expression.
void	updateKeys ()
	Update keys_ by collecting unique keys from all factors.
	NonlinearFactor ()
	Default constructor for I/O only.
template<typename CONTAINER>
	NonlinearFactor (const CONTAINER &keys)
	Constructor from a collection of the keys involved in this factor.
void	print (const std::string &s="", const KeyFormatter &keyFormatter=DefaultKeyFormatter) const override
	print
double	error (const HybridValues &c) const override
	All factor types need to implement an error function.
virtual bool	active (const Values &c) const
	Checks whether a factor should be used based on a set of values.
virtual void	qcqpFactors (NonlinearFactorGraph costs, NonlinearEqualityConstraints constraints, size_t columnDimension=1) const
	Add this factor's QCQP cost and constraints over matrix-valued QCQP variables with the given column dimension.
virtual shared_ptr	clone () const
	Creates a shared_ptr clone of the factor - needs to be specialized to allow for subclasses.
virtual shared_ptr	rekey (const std::map< Key, Key > &rekey_mapping) const
	Creates a shared_ptr clone of the factor with different keys using a map from old->new keys.
virtual shared_ptr	rekey (const KeyVector &new_keys) const
	Clones a factor and fully replaces its keys.
virtual bool	sendable () const
	Should the factor be evaluated in the same thread as the caller This is to enable factors that has shared states (like the Python GIL lock).
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 = NonlinearFactor
using	This = BatchFactor<FactorType, ErrorDim>
using	shared_ptr = std::shared_ptr<This>
using	FactorVector
Public Types inherited from gtsam::NonlinearFactor
typedef std::shared_ptr< This >	shared_ptr
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
Protected Types inherited from gtsam::NonlinearFactor
typedef Factor	Base
typedef NonlinearFactor	This
	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::Factor
KeyVector	keys_
	The keys involved in this factor.

Member Typedef Documentation

◆ FactorVector

template<typename FactorType, int ErrorDim>

using gtsam::BatchFactor< FactorType, ErrorDim >::FactorVector

Initial value:

std::vector<FactorType, Eigen::aligned_allocator<FactorType>>

Constructor & Destructor Documentation

◆ BatchFactor() [1/2]

template<typename FactorType, int ErrorDim>

template<typename Measurement, typename... Args>

gtsam::BatchFactor< FactorType, ErrorDim >::BatchFactor	(	Key	key1,
		const std::map< Key, Measurement > &	measurements,
		const SharedNoiseModel &	model,
		Args &&...	args )

inline

Map-based Constructor (Varying Key2).

Constructs factors from a map of measurements, where the map key is the second factor key.

Parameters

key1	The fixed first key (e.g., camera pose).
measurements	Map from Key (2nd key) to Measurement.
model	Noise model.
args	Extra arguments passed to the factor constructor.

◆ BatchFactor() [2/2]

template<typename FactorType, int ErrorDim>

template<typename Measurement, typename... Args>

gtsam::BatchFactor< FactorType, ErrorDim >::BatchFactor	(	const std::map< Key, Measurement > &	measurements,
		Key	key2,
		const SharedNoiseModel &	model,
		Args &&...	args )

inline

Map-based Constructor (Varying Key1).

Constructs factors from a map of measurements, where the map key is the first factor key.

Parameters

measurements	Map from Key (1st key) to Measurement.
key2	The fixed second key (e.g., landmark).
model	Noise model.
args	Extra arguments passed to the factor constructor.

Member Function Documentation

◆ dim()

template<typename FactorType, int ErrorDim>

size_t gtsam::BatchFactor< FactorType, ErrorDim >::dim ( ) const

inlineoverridevirtual

Get the dimension of the factor (number of rows on linearization).

Implements gtsam::NonlinearFactor.

◆ equals()

template<typename FactorType, int ErrorDim>

bool gtsam::BatchFactor< FactorType, ErrorDim >::equals	(	const NonlinearFactor &	f,
		double	tol = 1e-9 ) const

inlineoverridevirtual

Check equality with another factor.

Reimplemented from gtsam::NonlinearFactor.

◆ error()

template<typename FactorType, int ErrorDim>

double gtsam::BatchFactor< FactorType, ErrorDim >::error ( const Values & c ) const

inlineoverridevirtual

Calculate the error of the factor.

This is the sum of the errors of all internal factors.

Reimplemented from gtsam::NonlinearFactor.

◆ linearize()

template<typename FactorType, int ErrorDim>

std::shared_ptr< GaussianFactor > gtsam::BatchFactor< FactorType, ErrorDim >::linearize ( const Values & values ) const

inlineoverridevirtual

Linearize to a single JacobianFactor.

Optimization:

Pre-calculates the total size required for the JacobianFactor.
Collects all unique Keys involved across all sub-factors.
Iterates linearly over factors_ (cache-friendly) to compute Jacobians.
Fills the pre-allocated JacobianFactor directly.

Implements gtsam::NonlinearFactor.

◆ print()

template<typename FactorType, int ErrorDim>

void gtsam::BatchFactor< FactorType, ErrorDim >::print	(	const std::string &	s = "",
		const KeyFormatter &	keyFormatter = DefaultKeyFormatter ) const

inlineoverridevirtual

Print the BatchFactor.

Reimplemented from gtsam::Factor.

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

/tmp/gtsam-4.3.0-doxygen.rsXPUS/source/gtsam/nonlinear/BatchFactor.h

Detailed Description

Public Member Functions

Public Types

Additional Inherited Members

Member Typedef Documentation

◆ FactorVector

Constructor & Destructor Documentation

◆ BatchFactor() [1/2]

◆ BatchFactor() [2/2]

Member Function Documentation

◆ dim()

◆ equals()

◆ error()

◆ linearize()

◆ print()