gtsam::Signature Class Reference

Detailed Description

Signature for a discrete conditional density, used to construct conditionals.

The format is (Key % string) for nodes with no parents, and (Key | Key, Key = string) for nodes with parents.

The string specifies a conditional probability table in 00 01 10 11 order. For three-valued, it would be 00 01 02 10 11 12 20 21 22, etc...

For example, given the following keys

Key A("Asia"), S("Smoking"), T("Tuberculosis"), L("LungCancer"), B("Bronchitis"), E("Either"), X("XRay"), D("Dyspnoea");

These are all valid signatures (Asia network example):

A % "99/1" S % "50/50" T|A = "99/1 95/5" L|S = "99/1 90/10" B|S = "70/30 40/60" (E|T,L) = "F F F 1" X|E = "95/5 2/98" (D|E,B) = "9/1 2/8 3/7 1/9"

Public Member Functions
	Signature (const DiscreteKey &key, const DiscreteKeys &parents, const Table &table)
	Construct from key, parents, and a Signature::Table specifying the conditional probability table (CPT) in 00 01 10 11 order.
	Signature (const DiscreteKey &key, const DiscreteKeys &parents, const std::string &spec)
	Construct from key, parents, and a string specifying the conditional probability table (CPT) in 00 01 10 11 order.
	Signature (const DiscreteKey &key)
	Construct from a single DiscreteKey.
const DiscreteKey &	key () const
	the variable key
const DiscreteKeys &	parents () const
	the parent keys
DiscreteKeys	discreteKeys () const
	All keys, with variable key first.
KeyVector	indices () const
	All key indices, with variable key first.
const boost::optional< Table > &	table () const
std::vector< double >	cpt () const
Signature &	operator, (const DiscreteKey &parent)
	Add a parent.
Signature &	operator= (const std::string &spec)
	Add the CPT spec.
Signature &	operator= (const Table &table)
	Add the CPT spec directly as a table.

Public Types
typedef std::vector< double >	Row
	Data type for the CPT.
typedef std::vector< Row >	Table

Friends
GTSAM_EXPORT friend std::ostream &	operator<< (std::ostream &os, const Signature &s)
	provide streaming

Constructor & Destructor Documentation

Signature() [1/3]

gtsam::Signature::Signature	(	const DiscreteKey &	key,
		const DiscreteKeys &	parents,
		const Table &	table )

Construct from key, parents, and a Signature::Table specifying the conditional probability table (CPT) in 00 01 10 11 order.

For three-valued, it would be 00 01 02 10 11 12 20 21 22, etc....

The first string is parsed to add a key and parents.

Example: Signature::Table table{{0.9, 0.1}, {0.2, 0.8}, {0.3, 0.7}, {0.1, 0.9}}; Signature sig(D, {E, B}, table);

Signature() [2/3]

gtsam::Signature::Signature	(	const DiscreteKey &	key,
		const DiscreteKeys &	parents,
		const std::string &	spec )

Construct from key, parents, and a string specifying the conditional probability table (CPT) in 00 01 10 11 order.

For three-valued, it would be 00 01 02 10 11 12 20 21 22, etc....

The first string is parsed to add a key and parents. The second string parses into a table.

Example (same CPT as above): Signature sig(D, {B,E}, "9/1 2/8 3/7 1/9");

Signature() [3/3]

gtsam::Signature::Signature

(

const DiscreteKey &

key

)

Construct from a single DiscreteKey.

The resulting signature has no parents or CPT table. Typical use then either adds parents with | and , operators below, or assigns a table with operator=().

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

• /build/reproducible-path/gtsam-4.2.2+dfsg/gtsam/discrete/Signature.h
• /build/reproducible-path/gtsam-4.2.2+dfsg/gtsam/discrete/Signature.cpp