gtsam 4.1.1 gtsam
gtsam::NonlinearFactorGraph Class Reference

## Detailed Description

A non-linear factor graph is a graph of non-Gaussian, i.e.

non-linear factors, which derive from NonlinearFactor. The values structures are typically (in SAM) more general than just vectors, e.g., Rot3 or Pose3, which are objects in non-linear manifolds. Linearizing the non-linear factor graph creates a linear factor graph on the tangent vector space at the linearization point. Because the tangent space is a true vector space, the config type will be an VectorValues in that linearized factor graph.

Inheritance diagram for gtsam::NonlinearFactorGraph:

## Public Member Functions

NonlinearFactorGraph ()
Default constructor.

template<typename ITERATOR >
NonlinearFactorGraph (ITERATOR firstFactor, ITERATOR lastFactor)
Construct from iterator over factors.

template<class CONTAINER >
NonlinearFactorGraph (const CONTAINER &factors)
Construct from container of factors (shared_ptr or plain objects)

template<class DERIVEDFACTOR >
NonlinearFactorGraph (const FactorGraph< DERIVEDFACTOR > &graph)
Implicit copy/downcast constructor to override explicit template container constructor.

virtual ~NonlinearFactorGraph ()
Destructor.

void print (const std::string &str="NonlinearFactorGraph: ", const KeyFormatter &keyFormatter=DefaultKeyFormatter) const override
print More...

void printErrors (const Values &values, const std::string &str="NonlinearFactorGraph: ", const KeyFormatter &keyFormatter=DefaultKeyFormatter, const std::function< bool(const Factor *, double, size_t)> &printCondition=[](const Factor *, double, size_t) {return true;}) const
print errors along with factors

bool equals (const NonlinearFactorGraph &other, double tol=1e-9) const
Test equality.

void saveGraph (std::ostream &stm, const Values &values=Values(), const GraphvizFormatting &graphvizFormatting=GraphvizFormatting(), const KeyFormatter &keyFormatter=DefaultKeyFormatter) const
Write the graph in GraphViz format for visualization.

void saveGraph (const std::string &file, const Values &values=Values(), const GraphvizFormatting &graphvizFormatting=GraphvizFormatting(), const KeyFormatter &keyFormatter=DefaultKeyFormatter) const
Write the graph in GraphViz format to file for visualization. More...

double error (const Values &values) const
unnormalized error, $$0.5 \sum_i (h_i(X_i)-z)^2/\sigma^2$$ in the most common case

double probPrime (const Values &values) const
Unnormalized probability. More...

boost::shared_ptr< SymbolicFactorGraphsymbolic () const
Create a symbolic factor graph.

Ordering orderingCOLAMD () const
Compute a fill-reducing ordering using COLAMD.

Ordering orderingCOLAMDConstrained (const FastMap< Key, int > &constraints) const
Compute a fill-reducing ordering with constraints using CCOLAMD. More...

boost::shared_ptr< GaussianFactorGraphlinearize (const Values &linearizationPoint) const
Linearize a nonlinear factor graph.

boost::shared_ptr< HessianFactorlinearizeToHessianFactor (const Values &values, const Dampen &dampen=nullptr) const
Instead of producing a GaussianFactorGraph, pre-allocate and linearize directly into a HessianFactor. More...

boost::shared_ptr< HessianFactorlinearizeToHessianFactor (const Values &values, const Ordering &ordering, const Dampen &dampen=nullptr) const
Instead of producing a GaussianFactorGraph, pre-allocate and linearize directly into a HessianFactor. More...

Values updateCholesky (const Values &values, const Dampen &dampen=nullptr) const
Linearize and solve in one pass. More...

Values updateCholesky (const Values &values, const Ordering &ordering, const Dampen &dampen=nullptr) const
Linearize and solve in one pass. More...

NonlinearFactorGraph clone () const
Clone() performs a deep-copy of the graph, including all of the factors.

NonlinearFactorGraph rekey (const std::map< Key, Key > &rekey_mapping) const
Rekey() performs a deep-copy of all of the factors, and changes keys according to a mapping. More...

template<typename T >
void addExpressionFactor (const SharedNoiseModel &R, const T &z, const Expression< T > &h)
Directly add ExpressionFactor that implements |h(x)-z|^2_R. More...

template<typename T >
void addPrior (Key key, const T &prior, const SharedNoiseModel &model=nullptr)
Convenience method which adds a PriorFactor to the factor graph. More...

template<typename T >
void addPrior (Key key, const T &prior, const Matrix &covariance)
Convenience method which adds a PriorFactor to the factor graph. More...

Public Member Functions inherited from gtsam::FactorGraph< NonlinearFactor >
virtual ~FactorGraph ()=default
Default destructor.

void reserve (size_t size)
Reserve space for the specified number of factors if you know in advance how many there will be (works like FastVector::reserve).

IsDerived< DERIVEDFACTOR > push_back (boost::shared_ptr< DERIVEDFACTOR > factor)
Add a factor directly using a shared_ptr.

IsDerived< DERIVEDFACTOR > push_back (const DERIVEDFACTOR &factor)
Add a factor by value, will be copy-constructed (use push_back with a shared_ptr to avoid the copy).

IsDerived< DERIVEDFACTOR > emplace_shared (Args &&... args)
Emplace a shared pointer to factor of given type.

IsDerived< DERIVEDFACTOR > add (boost::shared_ptr< DERIVEDFACTOR > factor)
add is a synonym for push_back.

std::enable_if< std::is_base_of< FactorType, DERIVEDFACTOR >::value, boost::assign::list_inserter< RefCallPushBack< This > > >::type operator+= (boost::shared_ptr< DERIVEDFACTOR > factor)
+= works well with boost::assign list inserter.

HasDerivedElementType< ITERATOR > push_back (ITERATOR firstFactor, ITERATOR lastFactor)
Push back many factors with an iterator over shared_ptr (factors are not copied)

HasDerivedValueType< ITERATOR > push_back (ITERATOR firstFactor, ITERATOR lastFactor)
Push back many factors with an iterator (factors are copied)

HasDerivedElementType< CONTAINER > push_back (const CONTAINER &container)
Push back many factors as shared_ptr's in a container (factors are not copied)

HasDerivedValueType< CONTAINER > push_back (const CONTAINER &container)
Push back non-pointer objects in a container (factors are copied).

Add a factor or container of factors, including STL collections, BayesTrees, etc.

boost::assign::list_inserter< CRefCallPushBack< This > > operator+= (const FACTOR_OR_CONTAINER &factorOrContainer)
Add a factor or container of factors, including STL collections, BayesTrees, etc.

std::enable_if< std::is_base_of< This, typenameCLIQUE::FactorGraphType >::value >::type push_back (const BayesTree< CLIQUE > &bayesTree)
Push back a BayesTree as a collection of factors. More...

FactorIndices add_factors (const CONTAINER &factors, bool useEmptySlots=false)
Add new factors to a factor graph and returns a list of new factor indices, optionally finding and reusing empty factor slots.

bool equals (const This &fg, double tol=1e-9) const
Check equality.

size_t size () const
return the number of factors (including any null factors set by remove() ).

bool empty () const
Check if the graph is empty (null factors set by remove() will cause this to return false).

const sharedFactor at (size_t i) const
Get a specific factor by index (this checks array bounds and may throw an exception, as opposed to operator[] which does not).

sharedFactorat (size_t i)
Get a specific factor by index (this checks array bounds and may throw an exception, as opposed to operator[] which does not).

const sharedFactor operator[] (size_t i) const
Get a specific factor by index (this does not check array bounds, as opposed to at() which does).

sharedFactoroperator[] (size_t i)
Get a specific factor by index (this does not check array bounds, as opposed to at() which does).

const_iterator begin () const
Iterator to beginning of factors.

const_iterator end () const
Iterator to end of factors.

sharedFactor front () const
Get the first factor.

sharedFactor back () const
Get the last factor.

iterator begin ()
non-const STL-style begin()

iterator end ()
non-const STL-style end()

void resize (size_t size)
Directly resize the number of factors in the graph. More...

void remove (size_t i)
delete factor without re-arranging indexes by inserting a nullptr pointer

void replace (size_t index, sharedFactor factor)
replace a factor by index

iterator erase (iterator item)
Erase factor and rearrange other factors to take up the empty space.

iterator erase (iterator first, iterator last)
Erase factors and rearrange other factors to take up the empty space.

size_t nrFactors () const
return the number of non-null factors

KeySet keys () const
Potentially slow function to return all keys involved, sorted, as a set.

KeyVector keyVector () const
Potentially slow function to return all keys involved, sorted, as a vector.

bool exists (size_t idx) const
MATLAB interface utility: Checks whether a factor index idx exists in the graph and is a live pointer.

## Public Types

typedef FactorGraph< NonlinearFactorBase

typedef NonlinearFactorGraph This

typedef boost::shared_ptr< Thisshared_ptr

typedef std::function< void(const boost::shared_ptr< HessianFactor > &hessianFactor)> Dampen
typdef for dampen functions used below

Public Types inherited from gtsam::FactorGraph< NonlinearFactor >
typedef NonlinearFactor FactorType
factor type

typedef boost::shared_ptr< NonlinearFactorsharedFactor
Shared pointer to a factor.

typedef sharedFactor value_type

typedef FastVector< sharedFactor >::iterator iterator

typedef FastVector< sharedFactor >::const_iterator const_iterator

## Friends

class boost::serialization::access
Serialization function.

Protected Member Functions inherited from gtsam::FactorGraph< NonlinearFactor >
FactorGraph ()
Default constructor.

FactorGraph (ITERATOR firstFactor, ITERATOR lastFactor)
Constructor from iterator over factors (shared_ptr or plain objects)

FactorGraph (const CONTAINER &factors)
Construct from container of factors (shared_ptr or plain objects)

Protected Attributes inherited from gtsam::FactorGraph< NonlinearFactor >
FastVector< sharedFactorfactors_
concept check, makes sure FACTOR defines print and equals More...

## Member Function Documentation

template<typename T >
 void gtsam::NonlinearFactorGraph::addExpressionFactor ( const SharedNoiseModel & R, const T & z, const Expression< T > & h )
inline

Directly add ExpressionFactor that implements |h(x)-z|^2_R.

Parameters
 h expression that implements measurement function z measurement R model

template<typename T >
 void gtsam::NonlinearFactorGraph::addPrior ( Key key, const T & prior, const Matrix & covariance )
inline

Convenience method which adds a PriorFactor to the factor graph.

Parameters
 key Variable key prior The variable's prior value covariance Covariance matrix.

Note that the smart noise model associated with the prior factor automatically picks the right noise model (e.g. a diagonal noise model if the provided covariance matrix is diagonal).

template<typename T >
 void gtsam::NonlinearFactorGraph::addPrior ( Key key, const T & prior, const SharedNoiseModel & model = nullptr )
inline

Convenience method which adds a PriorFactor to the factor graph.

Parameters
 key Variable key prior The variable's prior value model Noise model for prior factor

## ◆ linearizeToHessianFactor() [1/2]

 HessianFactor::shared_ptr gtsam::NonlinearFactorGraph::linearizeToHessianFactor ( const Values & values, const Dampen & dampen = nullptr ) const

Instead of producing a GaussianFactorGraph, pre-allocate and linearize directly into a HessianFactor.

Avoids the many mallocs and pointer indirection in constructing a new graph, and hence useful in case a dense solve is appropriate for your problem. An optional lambda function can be used to apply damping on the filled Hessian. No parallelism is exploited, because all the factors write in the same memory.

## ◆ linearizeToHessianFactor() [2/2]

 HessianFactor::shared_ptr gtsam::NonlinearFactorGraph::linearizeToHessianFactor ( const Values & values, const Ordering & ordering, const Dampen & dampen = nullptr ) const

Instead of producing a GaussianFactorGraph, pre-allocate and linearize directly into a HessianFactor.

Avoids the many mallocs and pointer indirection in constructing a new graph, and hence useful in case a dense solve is appropriate for your problem. An ordering is given that still decides how the Hessian is laid out. An optional lambda function can be used to apply damping on the filled Hessian. No parallelism is exploited, because all the factors write in the same memory.

## ◆ orderingCOLAMDConstrained()

 Ordering gtsam::NonlinearFactorGraph::orderingCOLAMDConstrained ( const FastMap< Key, int > & constraints ) const

Compute a fill-reducing ordering with constraints using CCOLAMD.

Parameters
 constraints is a map of Key->group, where 0 is unconstrained, and higher group numbers are further back in the ordering. Only keys with nonzero group indices need to appear in the constraints, unconstrained is assumed for all other variables

## ◆ print()

 void gtsam::NonlinearFactorGraph::print ( const std::string & str = "NonlinearFactorGraph: ", const KeyFormatter & keyFormatter = DefaultKeyFormatter ) const
overridevirtual

print

Reimplemented from gtsam::FactorGraph< NonlinearFactor >.

## ◆ probPrime()

 double gtsam::NonlinearFactorGraph::probPrime ( const Values & values ) const

Unnormalized probability.

O(n)

## ◆ rekey()

 NonlinearFactorGraph gtsam::NonlinearFactorGraph::rekey ( const std::map< Key, Key > & rekey_mapping ) const

Rekey() performs a deep-copy of all of the factors, and changes keys according to a mapping.

Keys not specified in the mapping will remain unchanged.

Parameters
 rekey_mapping is a map of old->new keys
Returns
a cloned graph with updated keys

## ◆ saveGraph()

 void gtsam::NonlinearFactorGraph::saveGraph ( const std::string & file, const Values & values = Values(), const GraphvizFormatting & graphvizFormatting = GraphvizFormatting(), const KeyFormatter & keyFormatter = DefaultKeyFormatter ) const

Write the graph in GraphViz format to file for visualization.

This is a wrapper friendly version since wrapped languages don't have access to C++ streams.

## ◆ updateCholesky() [1/2]

 Values gtsam::NonlinearFactorGraph::updateCholesky ( const Values & values, const Dampen & dampen = nullptr ) const

Linearize and solve in one pass.

Calls linearizeToHessianFactor, densely solves the normal equations, and updates the values.

## ◆ updateCholesky() [2/2]

 Values gtsam::NonlinearFactorGraph::updateCholesky ( const Values & values, const Ordering & ordering, const Dampen & dampen = nullptr ) const

Linearize and solve in one pass.

Calls linearizeToHessianFactor, densely solves the normal equations, and updates the values.

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