#include <SubgraphSolver.h>

Inheritance diagram for gtsam::SubgraphSolver:

Public Types
typedef SubgraphSolverParameters	Parameters

Public Types inherited from gtsam::IterativeSolver
typedef std::shared_ptr< IterativeSolver >	shared_ptr

Protected Attributes
Parameters	parameters_

std::shared_ptr< SubgraphPreconditioner >	pc_
	preconditioner object More...

Constructors
	SubgraphSolver (const GaussianFactorGraph &A, const Parameters &parameters, const Ordering &ordering)

	SubgraphSolver (const GaussianFactorGraph &Ab1, const GaussianFactorGraph &Ab2, const Parameters &parameters, const Ordering &ordering)

	SubgraphSolver (const GaussianBayesNet &Rc1, const GaussianFactorGraph &Ab2, const Parameters &parameters)

	~SubgraphSolver () override
	Destructor. More...

Implement interface
VectorValues	optimize () const
	Optimize from zero. More...

VectorValues	optimize (const GaussianFactorGraph &gfg, const KeyInfo &keyInfo, const std::map< Key, Vector > &lambda, const VectorValues &initial) override
	Interface that IterativeSolver subclasses have to implement. More...

std::pair< GaussianFactorGraph, GaussianFactorGraph >	splitGraph (const GaussianFactorGraph &gfg)
	Split graph using Kruskal algorithm, treating binary factors as edges. More...

Additional Inherited Members
Public Member Functions inherited from gtsam::IterativeSolver
	IterativeSolver ()

GTSAM_EXPORT VectorValues	optimize (const GaussianFactorGraph &gfg, const KeyInfo =nullptr, const std::map< Key, Vector > lambda=nullptr)

GTSAM_EXPORT VectorValues	optimize (const GaussianFactorGraph &gfg, const KeyInfo &keyInfo, const std::map< Key, Vector > &lambda)

virtual	~IterativeSolver ()

Detailed Description

This class implements the linear SPCG solver presented in Dellaert et al in IROS'10.

$A_t $ is factorized into $ Q_t R_t $ , and we compute $c_t = Q_t^{-1} b_t$ , and $x_t = R_t^{-1} c_t$ accordingly.

Then we solve a reparametrized problem $f(y) = |y|^2 + |A_c R_t^{-1} y -\bar{b_y}|^2$ , where $ y = R_t(x - x_t) $ , and $\bar{b_y} = (b_c - A_c x_t)$

In the matrix form, it is equivalent to solving $[A_c R_t^{-1} ; I ] y = [\bar{b_y} ; 0]$ . We can solve it with the least-squares variation of the conjugate gradient method.

To use it in nonlinear optimization, please see the following example

LevenbergMarquardtParams parameters; parameters.linearSolverType = NonlinearOptimizerParams::CONJUGATE_GRADIENT; parameters.iterativeParams = std::make_shared<SubgraphSolverParameters>(); LevenbergMarquardtOptimizer optimizer(graph, initialEstimate, parameters); Values result = optimizer.optimize();

Definition at line 76 of file SubgraphSolver.h.

Member Typedef Documentation

◆ Parameters

typedef SubgraphSolverParameters gtsam::SubgraphSolver::Parameters

Definition at line 78 of file SubgraphSolver.h.

Constructor & Destructor Documentation

◆ SubgraphSolver() [1/3]

gtsam::SubgraphSolver::SubgraphSolver	(	const GaussianFactorGraph &	A,
		const Parameters &	parameters,
		const Ordering &	ordering
	)

Given a gaussian factor graph, split it into a spanning tree (A1) + others (A2) for SPCG Will throw exception if there are ternary factors or higher arity, as we use Kruskal's algorithm to split the graph, treating binary factors as edges.

Definition at line 34 of file SubgraphSolver.cpp.

◆ SubgraphSolver() [2/3]

gtsam::SubgraphSolver::SubgraphSolver	(	const GaussianFactorGraph &	Ab1,
		const GaussianFactorGraph &	Ab2,
		const Parameters &	parameters,
		const Ordering &	ordering
	)

The user specifies the subgraph part and the constraints part. May throw exception if A1 is underdetermined. An ordering is required to eliminate Ab1. We take Ab1 as a const reference, as it will be transformed into Rc1, but take Ab2 as a shared pointer as we need to keep it around.

Definition at line 60 of file SubgraphSolver.cpp.

◆ SubgraphSolver() [3/3]

gtsam::SubgraphSolver::SubgraphSolver	(	const GaussianBayesNet &	Rc1,
		const GaussianFactorGraph &	Ab2,
		const Parameters &	parameters
	)

The same as above, but we assume A1 was solved by caller. We take two shared pointers as we keep both around.

Definition at line 49 of file SubgraphSolver.cpp.

◆ ~SubgraphSolver()

gtsam::SubgraphSolver::~SubgraphSolver ( )

inlineoverride

Destructor.

Definition at line 112 of file SubgraphSolver.h.

Member Function Documentation

◆ optimize() [1/2]

VectorValues gtsam::SubgraphSolver::optimize ( ) const

Optimize from zero.

Definition at line 68 of file SubgraphSolver.cpp.

◆ optimize() [2/2]

VectorValues gtsam::SubgraphSolver::optimize	(	const GaussianFactorGraph &	gfg,
		const KeyInfo &	keyInfo,
		const std::map< Key, Vector > &	lambda,
		const VectorValues &	initial
	)

overridevirtual

Interface that IterativeSolver subclasses have to implement.

Implements gtsam::IterativeSolver.

Definition at line 74 of file SubgraphSolver.cpp.

◆ splitGraph()

pair< GaussianFactorGraph, GaussianFactorGraph > gtsam::SubgraphSolver::splitGraph ( const GaussianFactorGraph & gfg )

Split graph using Kruskal algorithm, treating binary factors as edges.

Definition at line 81 of file SubgraphSolver.cpp.

Member Data Documentation

◆ parameters_

Parameters gtsam::SubgraphSolver::parameters_

protected

Definition at line 81 of file SubgraphSolver.h.

◆ pc_

std::shared_ptr<SubgraphPreconditioner> gtsam::SubgraphSolver::pc_

protected

preconditioner object

Definition at line 82 of file SubgraphSolver.h.

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

Public Types

Protected Attributes

Constructors

Implement interface

Additional Inherited Members