88 lines
2.7 KiB
C++
88 lines
2.7 KiB
C++
/*
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* SingleValue.h
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* @brief domain constraint
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* @date Feb 6, 2012
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* @author Frank Dellaert
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*/
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#pragma once
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#include <gtsam/discrete/DiscreteKey.h>
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#include <gtsam_unstable/discrete/Constraint.h>
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namespace gtsam {
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/**
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* SingleValue constraint: ensures a variable takes on a certain value.
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* This could of course also be implemented by changing its `Domain`.
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*/
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class GTSAM_UNSTABLE_EXPORT SingleValue : public Constraint {
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size_t cardinality_; /// < Number of values
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size_t value_; ///< allowed value
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DiscreteKey discreteKey() const {
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return DiscreteKey(keys_[0], cardinality_);
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}
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public:
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typedef std::shared_ptr<SingleValue> shared_ptr;
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/// Construct from key, cardinality, and given value.
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SingleValue(Key key, size_t n, size_t value)
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: Constraint(key), cardinality_(n), value_(value) {}
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/// Construct from DiscreteKey and given value.
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SingleValue(const DiscreteKey& dkey, size_t value)
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: Constraint(dkey.first), cardinality_(dkey.second), value_(value) {}
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// print
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void print(const std::string& s = "", const KeyFormatter& formatter =
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DefaultKeyFormatter) const override;
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/// equals
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bool equals(const DiscreteFactor& other, double tol) const override {
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if (!dynamic_cast<const SingleValue*>(&other))
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return false;
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else {
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const SingleValue& f(static_cast<const SingleValue&>(other));
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return (cardinality_ == f.cardinality_) && (value_ == f.value_);
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}
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}
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/// Compute error for each assignment and return as a tree
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AlgebraicDecisionTree<Key> errorTree() const override {
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throw std::runtime_error("SingleValue::error not implemented");
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}
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/// Calculate value
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double evaluate(const Assignment<Key>& values) const override;
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/// Convert into a decisiontree
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DecisionTreeFactor toDecisionTreeFactor() const override;
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/// Multiply into a decisiontree
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DecisionTreeFactor operator*(const DecisionTreeFactor& f) const override;
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/*
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* Ensure Arc-consistency: just sets domain[j] to {value_}.
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* @param j domain to be checked
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* @param (in/out) domains all domains, but only domains->at(j) will be checked.
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* @return true if domains->at(j) was changed, false otherwise.
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*/
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bool ensureArcConsistency(Key j, Domains* domains) const override;
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/// Partially apply known values
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Constraint::shared_ptr partiallyApply(const DiscreteValues& values) const override;
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/// Partially apply known values, domain version
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Constraint::shared_ptr partiallyApply(
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const Domains& domains) const override;
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// Scale just returns the same constraint.
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DiscreteFactor::shared_ptr scale() const override {
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return std::make_shared<SingleValue>(*this);
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}
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};
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} // namespace gtsam
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