61 lines
1.6 KiB
C++
61 lines
1.6 KiB
C++
/**
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* @file Factor.h
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* @brief A simple factor class to use in a factor graph
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* @brief factor
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* @author Kai Ni
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* @author Frank Dellaert
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*/
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// \callgraph
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#pragma once
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#include <list>
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#include <boost/utility.hpp> // for noncopyable
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#include "Testable.h"
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#include "Key.h"
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#include "SymbolMap.h"
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namespace gtsam {
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/** A map from key to dimension, useful in various contexts */
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typedef SymbolMap<int> Dimensions;
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/**
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* A simple factor class to use in a factor graph.
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*
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* We make it noncopyable so we enforce the fact that factors are
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* kept in pointer containers. To be safe, you should make them
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* immutable, i.e., practicing functional programming. However, this
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* conflicts with efficiency as well, esp. in the case of incomplete
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* QR factorization. A solution is still being sought.
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*
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* A Factor is templated on a Config, for example VectorConfig is a configuration of
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* labeled vectors. This way, we can have factors that might be defined on discrete
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* variables, continuous ones, or a combination of both. It is up to the config to
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* provide the appropriate values at the appropriate time.
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*/
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template <class Config>
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class Factor : public Testable< Factor<Config> >
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{
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public:
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virtual ~Factor() {};
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/**
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* negative log probability
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*/
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virtual double error(const Config& c) const = 0;
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/**
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* return keys in preferred order
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*/
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virtual std::list<Symbol> keys() const = 0;
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/**
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* @return the number of nodes the factor connects
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*/
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virtual std::size_t size() const = 0;
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};
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}
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