gtsam  4.1.0 gtsam
gtsam::GaussianConditional Class Reference

## Detailed Description

A conditional Gaussian functions as the node in a Bayes network It has a set of parents y,z, etc.

and implements a probability density on x. The negative log-probability is given by $$\frac{1}{2} |Rx - (d - Sy - Tz - ...)|^2$$

Inheritance diagram for gtsam::GaussianConditional:

## Public Member Functions

GaussianConditional ()
default constructor needed for serialization

GaussianConditional (Key key, const Vector &d, const Matrix &R, const SharedDiagonal &sigmas=SharedDiagonal())
constructor with no parents |Rx-d|

GaussianConditional (Key key, const Vector &d, const Matrix &R, Key name1, const Matrix &S, const SharedDiagonal &sigmas=SharedDiagonal())
constructor with only one parent |Rx+Sy-d|

GaussianConditional (Key key, const Vector &d, const Matrix &R, Key name1, const Matrix &S, Key name2, const Matrix &T, const SharedDiagonal &sigmas=SharedDiagonal())
constructor with two parents |Rx+Sy+Tz-d|

template<typename TERMS >
GaussianConditional (const TERMS &terms, size_t nrFrontals, const Vector &d, const SharedDiagonal &sigmas=SharedDiagonal())
Constructor with arbitrary number of frontals and parents. More...

template<typename KEYS >
GaussianConditional (const KEYS &keys, size_t nrFrontals, const VerticalBlockMatrix &augmentedMatrix, const SharedDiagonal &sigmas=SharedDiagonal())
Constructor with arbitrary number keys, and where the augmented matrix is given all together instead of in block terms. More...

void print (const std::string &="GaussianConditional", const KeyFormatter &formatter=DefaultKeyFormatter) const override
print

bool equals (const GaussianFactor &cg, double tol=1e-9) const override
equals function

constABlock R () const
Return a view of the upper-triangular R block of the conditional.

constABlock S () const
Get a view of the parent blocks.

constABlock S (const_iterator it) const
Get a view of the S matrix for the variable pointed to by the given key iterator.

const constBVector d () const
Get a view of the r.h.s. More...

VectorValues solve (const VectorValues &parents) const
Solves a conditional Gaussian and writes the solution into the entries of x for each frontal variable of the conditional. More...

VectorValues solveOtherRHS (const VectorValues &parents, const VectorValues &rhs) const

void solveTransposeInPlace (VectorValues &gy) const
Performs transpose backsubstition in place on values.

void scaleFrontalsBySigma (VectorValues &gy) const
Scale the values in gy according to the sigmas for the frontal variables in this conditional.

Public Member Functions inherited from gtsam::JacobianFactor
JacobianFactor (const GaussianFactor &gf)
Convert from other GaussianFactor.

JacobianFactor (const JacobianFactor &jf)
Copy constructor.

JacobianFactor (const HessianFactor &hf)
Conversion from HessianFactor (does Cholesky to obtain Jacobian matrix)

JacobianFactor ()
default constructor for I/O

JacobianFactor (const Vector &b_in)
Construct Null factor.

JacobianFactor (Key i1, const Matrix &A1, const Vector &b, const SharedDiagonal &model=SharedDiagonal())
Construct unary factor.

JacobianFactor (Key i1, const Matrix &A1, Key i2, const Matrix &A2, const Vector &b, const SharedDiagonal &model=SharedDiagonal())
Construct binary factor.

JacobianFactor (Key i1, const Matrix &A1, Key i2, const Matrix &A2, Key i3, const Matrix &A3, const Vector &b, const SharedDiagonal &model=SharedDiagonal())
Construct ternary factor.

template<typename TERMS >
JacobianFactor (const TERMS &terms, const Vector &b, const SharedDiagonal &model=SharedDiagonal())
Construct an n-ary factor. More...

template<typename KEYS >
JacobianFactor (const KEYS &keys, const VerticalBlockMatrix &augmentedMatrix, const SharedDiagonal &sigmas=SharedDiagonal())
Constructor with arbitrary number keys, and where the augmented matrix is given all together instead of in block terms. More...

JacobianFactor (const GaussianFactorGraph &graph)
Build a dense joint factor from all the factors in a factor graph. More...

JacobianFactor (const GaussianFactorGraph &graph, const VariableSlots &p_variableSlots)
Build a dense joint factor from all the factors in a factor graph. More...

JacobianFactor (const GaussianFactorGraph &graph, const Ordering &ordering)
Build a dense joint factor from all the factors in a factor graph. More...

JacobianFactor (const GaussianFactorGraph &graph, const Ordering &ordering, const VariableSlots &p_variableSlots)
Build a dense joint factor from all the factors in a factor graph. More...

virtual ~JacobianFactor ()
Virtual destructor.

GaussianFactor::shared_ptr clone () const override
Clone this JacobianFactor.

void print (const std::string &s="", const KeyFormatter &formatter=DefaultKeyFormatter) const override

bool equals (const GaussianFactor &lf, double tol=1e-9) const override
Equals for testable.

Vector unweighted_error (const VectorValues &c) const

Vector error_vector (const VectorValues &c) const
(A*x-b)

double error (const VectorValues &c) const override
(A*x-b)/sigma

Matrix augmentedInformation () const override
0.5*(A*x-b)'D(A*x-b) More...

Matrix information () const override
Return the non-augmented information matrix represented by this GaussianFactor.

void hessianDiagonalAdd (VectorValues &d) const override
Add the current diagonal to a VectorValues instance.

void hessianDiagonal (double *d) const override
Raw memory access version of hessianDiagonal.

std::map< Key, Matrix > hessianBlockDiagonal () const override
Return the block diagonal of the Hessian for this factor.

std::pair< Matrix, Vector > jacobian () const override
Returns (dense) A,b pair associated with factor, bakes in the weights.

std::pair< Matrix, Vector > jacobianUnweighted () const
Returns (dense) A,b pair associated with factor, does not bake in weights.

Matrix augmentedJacobian () const override
Return (dense) matrix associated with factor. More...

Matrix augmentedJacobianUnweighted () const
Return (dense) matrix associated with factor. More...

const VerticalBlockMatrixmatrixObject () const
Return the full augmented Jacobian matrix of this factor as a VerticalBlockMatrix object.

VerticalBlockMatrixmatrixObject ()
Mutable access to the full augmented Jacobian matrix of this factor as a VerticalBlockMatrix object.

GaussianFactor::shared_ptr negate () const override
Construct the corresponding anti-factor to negate information stored stored in this factor. More...

bool empty () const override
Check if the factor is empty. More...

bool isConstrained () const
is noise model constrained ?

DenseIndex getDim (const_iterator variable) const override
Return the dimension of the variable pointed to by the given key iterator todo: Remove this in favor of keeping track of dimensions with variables?

size_t rows () const
return the number of rows in the corresponding linear system

size_t cols () const
return the number of columns in the corresponding linear system

const SharedDiagonal & get_model () const
get a copy of model

SharedDiagonal & get_model ()
get a copy of model (non-const version)

const constBVector getb () const
Get a view of the r.h.s. More...

constABlock getA (const_iterator variable) const
Get a view of the A matrix for the variable pointed to by the given key iterator.

constABlock getA () const
Get a view of the A matrix, not weighted by noise.

BVector getb ()
Get a view of the r.h.s. More...

ABlock getA (iterator variable)
Get a view of the A matrix for the variable pointed to by the given key iterator (non-const version)

ABlock getA ()
Get a view of the A matrix.

void updateHessian (const KeyVector &keys, SymmetricBlockMatrix *info) const override
Update an information matrix by adding the information corresponding to this factor (used internally during elimination). More...

Vector operator* (const VectorValues &x) const
Return A*x.

void transposeMultiplyAdd (double alpha, const Vector &e, VectorValues &x) const
x += alpha * A'*e. More...

void multiplyHessianAdd (double alpha, const VectorValues &x, VectorValues &y) const override
y += alpha * A'*A*x

void multiplyHessianAdd (double alpha, const double *x, double *y, const std::vector< size_t > &accumulatedDims) const
Raw memory access version of multiplyHessianAdd y += alpha * A'*A*x Requires the vector accumulatedDims to tell the dimension of each variable: e.g. More...

A'*b for Jacobian.

void gradientAtZero (double *d) const override
A'*b for Jacobian (raw memory version)

Vector gradient (Key key, const VectorValues &x) const override
Compute the gradient wrt a key at any values.

JacobianFactor whiten () const
Return a whitened version of the factor, i.e. More...

std::pair< boost::shared_ptr< GaussianConditional >, shared_ptreliminate (const Ordering &keys)
Eliminate the requested variables.

void setModel (bool anyConstrained, const Vector &sigmas)
set noiseModel correctly

boost::shared_ptr< GaussianConditionalsplitConditional (size_t nrFrontals)
splits a pre-factorized factor into a conditional, and changes the current factor to be the remaining component. More...

Public Member Functions inherited from gtsam::GaussianFactor
GaussianFactor ()
Default constructor creates empty factor.

template<typename CONTAINER >
GaussianFactor (const CONTAINER &keys)
Construct from container of keys. More...

virtual ~GaussianFactor ()
Destructor.

VectorValues hessianDiagonal () const
Return the diagonal of the Hessian for this factor.

Public Member Functions inherited from gtsam::Factor
Key front () const
First key.

Key back () const
Last key.

const_iterator find (Key key) const
find

const KeyVectorkeys () 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

void print (const std::string &s="Factor", const KeyFormatter &formatter=DefaultKeyFormatter) const
print

void printKeys (const std::string &s="Factor", const KeyFormatter &formatter=DefaultKeyFormatter) const
print only keys

KeyVectorkeys ()

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< JacobianFactor, GaussianConditional >
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

FACTOR::const_iterator beginFrontals () const
Iterator pointing to first frontal key.

FACTOR::const_iterator endFrontals () const
Iterator pointing past the last frontal key.

FACTOR::const_iterator beginParents () const
Iterator pointing to the first parent key.

FACTOR::const_iterator endParents () const
Iterator pointing past the last parent key.

size_t & nrFrontals ()
Mutable version of nrFrontals.

FACTOR::iterator beginFrontals ()
Mutable iterator pointing to first frontal key.

FACTOR::iterator endFrontals ()
Mutable iterator pointing past the last frontal key.

FACTOR::iterator beginParents ()
Mutable iterator pointing to the first parent key.

FACTOR::iterator endParents ()
Mutable iterator pointing past the last parent key.

## Static Public Member Functions

template<typename ITERATOR >
static shared_ptr Combine (ITERATOR firstConditional, ITERATOR lastConditional)
Combine several GaussianConditional into a single dense GC. More...

Static Public Member Functions inherited from gtsam::GaussianFactor
template<typename CONTAINER >
static DenseIndex Slot (const CONTAINER &keys, Key key)

## Public Types

typedef GaussianConditional This
Typedef to this class.

typedef boost::shared_ptr< Thisshared_ptr
shared_ptr to this class

typedef JacobianFactor BaseFactor
Typedef to our factor base class.

typedef Conditional< BaseFactor, ThisBaseConditional
Typedef to our conditional base class.

Public Types inherited from gtsam::JacobianFactor
typedef JacobianFactor This
Typedef to this class.

typedef GaussianFactor Base
Typedef to base class.

typedef boost::shared_ptr< Thisshared_ptr
shared_ptr to this class

typedef VerticalBlockMatrix::Block ABlock

typedef VerticalBlockMatrix::constBlock constABlock

typedef ABlock::ColXpr BVector

typedef constABlock::ConstColXpr constBVector

Public Types inherited from gtsam::GaussianFactor
typedef GaussianFactor This
This class.

typedef boost::shared_ptr< Thisshared_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< JacobianFactor, GaussianConditional >
typedef boost::iterator_range< typename FACTOR::const_iterator > Frontals
View of the frontal keys (call frontals())

typedef boost::iterator_range< typename FACTOR::const_iterator > Parents
View of the separator keys (call parents())

## Friends

class boost::serialization::access
Serialization function.

Protected Member Functions inherited from gtsam::JacobianFactor
template<typename TERMS >
void fillTerms (const TERMS &terms, const Vector &b, const SharedDiagonal &noiseModel)
Internal function to fill blocks and set dimensions.

Protected Member Functions inherited from gtsam::Factor
Factor ()
Default constructor for I/O.

template<typename CONTAINER >
Factor (const CONTAINER &keys)
Construct factor from container of keys. More...

template<typename ITERATOR >
Factor (ITERATOR first, ITERATOR last)
Construct factor from iterator keys. More...

bool equals (const This &other, double tol=1e-9) const
check equality

Protected Member Functions inherited from gtsam::Conditional< JacobianFactor, GaussianConditional >
Conditional ()
Empty Constructor to make serialization possible.

Conditional (size_t nrFrontals)
Constructor.

Static Protected Member Functions inherited from gtsam::Factor
template<typename CONTAINER >
static Factor FromKeys (const CONTAINER &keys)
Construct factor from container of keys. More...

template<typename ITERATOR >
static Factor FromIterators (ITERATOR first, ITERATOR last)
Construct factor from iterator keys. More...

Protected Attributes inherited from gtsam::JacobianFactor
VerticalBlockMatrix Ab_

noiseModel::Diagonal::shared_ptr model_

Protected Attributes inherited from gtsam::Factor
KeyVector keys_
The keys involved in this factor.

Protected Attributes inherited from gtsam::Conditional< JacobianFactor, GaussianConditional >
size_t nrFrontals_
The first nrFrontal variables are frontal and the rest are parents.

## ◆ GaussianConditional() [1/2]

template<typename TERMS >
 gtsam::GaussianConditional::GaussianConditional ( const TERMS & terms, size_t nrFrontals, const Vector & d, const SharedDiagonal & sigmas = SharedDiagonal() )

Constructor with arbitrary number of frontals and parents.

Template Parameters
 TERMS A container whose value type is std::pair, specifying the collection of keys and matrices making up the conditional.

## ◆ GaussianConditional() [2/2]

template<typename KEYS >
 gtsam::GaussianConditional::GaussianConditional ( const KEYS & keys, size_t nrFrontals, const VerticalBlockMatrix & augmentedMatrix, const SharedDiagonal & sigmas = SharedDiagonal() )

Constructor with arbitrary number keys, and where the augmented matrix is given all together instead of in block terms.

Note that only the active view of the provided augmented matrix is used, and that the matrix data is copied into a newly-allocated matrix in the constructed factor.

## ◆ Combine()

template<typename ITERATOR >
 static shared_ptr gtsam::GaussianConditional::Combine ( ITERATOR firstConditional, ITERATOR lastConditional )
static

Combine several GaussianConditional into a single dense GC.

The conditionals enumerated by first and last must be in increasing order, meaning that the parents of any conditional may not include a conditional coming before it.

Parameters
 firstConditional Iterator to the first conditional to combine, must dereference to a shared_ptr. lastConditional Iterator to after the last conditional to combine, must dereference to a shared_ptr.

## ◆ d()

 const constBVector gtsam::GaussianConditional::d ( ) const
inline

Get a view of the r.h.s.

vector d

## ◆ solve()

 VectorValues gtsam::GaussianConditional::solve ( const VectorValues & parents ) const

Solves a conditional Gaussian and writes the solution into the entries of x for each frontal variable of the conditional.

The parents are assumed to have already been solved in and their values are read from x. This function works for multiple frontal variables.

Given the Gaussian conditional with log likelihood $$|R x_f - (d - S x_s)|^2$$, where $$f$$ are the frontal variables and $$s$$ are the separator variables of this conditional, this solve function computes $$x_f = R^{-1} (d - S x_s)$$ using back-substitution.

Parameters
 parents VectorValues containing solved parents $$x_s$$.

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