Public Member Functions
	ISAM2Params (OptimizationParams _optimizationParams=ISAM2GaussNewtonParams(), RelinearizationThreshold _relinearizeThreshold=0.1, int _relinearizeSkip=10, bool _enableRelinearization=true, bool _evaluateNonlinearError=false, Factorization _factorization=ISAM2Params::CHOLESKY, bool _cacheLinearizedFactors=true, const KeyFormatter &_keyFormatter=DefaultKeyFormatter)
	Specify parameters as constructor arguments See the documentation of member variables above. More...

void	print (const std::string &str="") const
	print iSAM2 parameters

Getters and Setters for all properties
OptimizationParams	getOptimizationParams () const

RelinearizationThreshold	getRelinearizeThreshold () const

int	getRelinearizeSkip () const

bool	isEnableRelinearization () const

bool	isEvaluateNonlinearError () const

std::string	getFactorization () const

bool	isCacheLinearizedFactors () const

KeyFormatter	getKeyFormatter () const

bool	isEnableDetailedResults () const

bool	isEnablePartialRelinearizationCheck () const

void	setOptimizationParams (OptimizationParams optimizationParams)

void	setRelinearizeThreshold (RelinearizationThreshold relinearizeThreshold)

void	setRelinearizeSkip (int relinearizeSkip)

void	setEnableRelinearization (bool enableRelinearization)

void	setEvaluateNonlinearError (bool evaluateNonlinearError)

void	setFactorization (const std::string &factorization)

void	setCacheLinearizedFactors (bool cacheLinearizedFactors)

void	setKeyFormatter (KeyFormatter keyFormatter)

void	setEnableDetailedResults (bool enableDetailedResults)

void	setEnablePartialRelinearizationCheck (bool enablePartialRelinearizationCheck)

GaussianFactorGraph::Eliminate	getEliminationFunction () const

Static Public Member Functions
Some utilities
static Factorization	factorizationTranslator (const std::string &str)

static std::string	factorizationTranslator (const Factorization &value)

Public Attributes
OptimizationParams	optimizationParams
	Optimization parameters, this both selects the nonlinear optimization method and specifies its parameters, either ISAM2GaussNewtonParams or ISAM2DoglegParams. More...

RelinearizationThreshold	relinearizeThreshold
	Only relinearize variables whose linear delta magnitude is greater than this threshold (default: 0.1). More...

int	relinearizeSkip
	Only relinearize any variables every relinearizeSkip calls to ISAM2::update (default: 10)

bool	enableRelinearization
	Controls whether ISAM2 will ever relinearize any variables (default: true)

bool	evaluateNonlinearError
	Whether to evaluate the nonlinear error before and after the update, to return in ISAM2Result from update()

Factorization	factorization
	Specifies whether to use QR or CHOESKY numerical factorization (default: CHOLESKY). More...

bool	cacheLinearizedFactors
	Whether to cache linear factors (default: true). More...

KeyFormatter	keyFormatter
	A KeyFormatter for when keys are printed during debugging (default: DefaultKeyFormatter)

bool	enableDetailedResults
	Whether to compute and return ISAM2Result::detailedResults, this can increase running time (default: false)

bool	enablePartialRelinearizationCheck
	Check variables for relinearization in tree-order, stopping the check once a variable does not need to be relinearized (default: false). More...

bool	findUnusedFactorSlots
	When you will be removing many factors, e.g. More...

Public Types
enum	Factorization { CHOLESKY, QR }

typedef boost::variant< ISAM2GaussNewtonParams, ISAM2DoglegParams >	OptimizationParams
	Either ISAM2GaussNewtonParams or ISAM2DoglegParams.

typedef boost::variant< double, FastMap< char, Vector > >	RelinearizationThreshold
	Either a constant relinearization threshold or a per-variable-type set of thresholds.

Constructor & Destructor Documentation

◆ ISAM2Params()

gtsam::ISAM2Params::ISAM2Params	(	OptimizationParams	_optimizationParams = `ISAM2GaussNewtonParams()`,
		RelinearizationThreshold	_relinearizeThreshold = `0.1`,
		int	_relinearizeSkip = `10`,
		bool	_enableRelinearization = `true`,
		bool	_evaluateNonlinearError = `false`,
		Factorization	_factorization = `ISAM2Params::CHOLESKY`,
		bool	_cacheLinearizedFactors = `true`,
		const KeyFormatter &	_keyFormatter = `DefaultKeyFormatter`
	)

inline

Specify parameters as constructor arguments See the documentation of member variables above.

Parameters

_keyFormatter see ISAM2::Params::keyFormatter

Member Data Documentation

◆ cacheLinearizedFactors

bool gtsam::ISAM2Params::cacheLinearizedFactors

Whether to cache linear factors (default: true).

This can improve performance if linearization is expensive, but can hurt performance if linearization is very cleap due to computation to look up additional keys.

◆ enablePartialRelinearizationCheck

bool gtsam::ISAM2Params::enablePartialRelinearizationCheck

Check variables for relinearization in tree-order, stopping the check once a variable does not need to be relinearized (default: false).

This can improve speed by only checking a small part of the top of the tree. However, variables below the check cut-off can accumulate significant deltas without triggering relinearization. This is particularly useful in exploration scenarios where real-time performance is desired over correctness. Use with caution.

◆ factorization

Factorization gtsam::ISAM2Params::factorization

Specifies whether to use QR or CHOESKY numerical factorization (default: CHOLESKY).

Cholesky is faster but potentially numerically unstable for poorly-conditioned problems, which can occur when uncertainty is very low in some variables (or dimensions of variables) and very high in others. QR is slower but more numerically stable in poorly-conditioned problems. We suggest using the default of Cholesky unless gtsam sometimes throws IndefiniteLinearSystemException when your problem's Hessian is actually positive definite. For positive definite problems, numerical error accumulation can cause the problem to become numerically negative or indefinite as solving proceeds, especially when using Cholesky.

◆ findUnusedFactorSlots

bool gtsam::ISAM2Params::findUnusedFactorSlots

When you will be removing many factors, e.g.

when using ISAM2 as a fixed-lag smoother, enable this option to add factors in the first available factor slots, to avoid accumulating NULL factor slots, at the cost of having to search for slots every time a factor is added.

◆ optimizationParams

OptimizationParams gtsam::ISAM2Params::optimizationParams

Optimization parameters, this both selects the nonlinear optimization method and specifies its parameters, either ISAM2GaussNewtonParams or ISAM2DoglegParams.

In the former, Gauss-Newton optimization will be used with the specified parameters, and in the latter Powell's dog-leg algorithm will be used with the specified parameters.

◆ relinearizeThreshold

RelinearizationThreshold gtsam::ISAM2Params::relinearizeThreshold

Only relinearize variables whose linear delta magnitude is greater than this threshold (default: 0.1).

If this is a FastMap<char,Vector> instead of a double, then the threshold is specified for each dimension of each variable type. This parameter then maps from a character indicating the variable type to a Vector of thresholds for each dimension of that variable. For example, if Pose keys are of type TypedSymbol<'x',Pose3>, and landmark keys are of type TypedSymbol<'l',Point3>, then appropriate entries would be added with:

  FastMap<char,Vector> thresholds;
  thresholds['x'] = (Vector(6) << 0.1, 0.1, 0.1, 0.5, 0.5, 0.5).finished();
// 0.1 rad rotation threshold, 0.5 m translation threshold thresholds['l'] =
Vector3(1.0, 1.0, 1.0);                // 1.0 m landmark position threshold
  params.relinearizeThreshold = thresholds;

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

/Users/dellaert/git/gtsam/gtsam/nonlinear/ISAM2Params.h
/Users/dellaert/git/gtsam/gtsam/nonlinear/ISAM2Params.cpp

Public Member Functions

Static Public Member Functions

Public Attributes

Public Types