gtsam/gtsam_unstable/discrete/Domain.h

/*
 * Domain.h
 * @brief Domain restriction constraint
 * @date Feb 13, 2012
 * @author Frank Dellaert
 */

#pragma once

#include <gtsam_unstable/discrete/Constraint.h>
#include <gtsam/discrete/DiscreteKey.h>

namespace gtsam {

  /**
   * Domain restriction constraint
   */
  class GTSAM_UNSTABLE_EXPORT Domain: public Constraint {

    size_t cardinality_; /// Cardinality
    std::set<size_t> values_; /// allowed values

  public:

    typedef boost::shared_ptr<Domain> shared_ptr;

    // Constructor on Discrete Key initializes an "all-allowed" domain
    Domain(const DiscreteKey& dkey) :
      Constraint(dkey.first), cardinality_(dkey.second) {
      for (size_t v = 0; v < cardinality_; v++)
        values_.insert(v);
    }

    // Constructor on Discrete Key with single allowed value
    // Consider SingleValue constraint
    Domain(const DiscreteKey& dkey, size_t v) :
      Constraint(dkey.first), cardinality_(dkey.second) {
      values_.insert(v);
    }

    /// Constructor
    Domain(const Domain& other) :
      Constraint(other.keys_[0]), values_(other.values_) {
    }

    /// insert a value, non const :-(
    void insert(size_t value) {
      values_.insert(value);
    }

    /// erase a value, non const :-(
    void erase(size_t value) {
       values_.erase(value);
    }

    size_t nrValues() const {
      return values_.size();
    }

    bool isSingleton() const {
      return nrValues() == 1;
    }

    size_t firstValue() const {
      return *values_.begin();
    }

    // print
    virtual void print(const std::string& s = "",
        const IndexFormatter& formatter = DefaultIndexFormatter) const;

    bool contains(size_t value) const {
      return values_.count(value)>0;
    }

    /// Calculate value
    virtual double operator()(const Values& values) const;

    /// Convert into a decisiontree
    virtual DecisionTreeFactor toDecisionTreeFactor() const;

    /// Multiply into a decisiontree
    virtual DecisionTreeFactor operator*(const DecisionTreeFactor& f) const;

    /*
     * Ensure Arc-consistency
     * @param j domain to be checked
     * @param domains all other domains
     */
    bool ensureArcConsistency(size_t j, std::vector<Domain>& domains) const;

    /**
     *  Check for a value in domain that does not occur in any other connected domain.
     *  If found, we make this a singleton... Called in AllDiff::ensureArcConsistency
     *  @param keys connected domains through alldiff
     */
    bool checkAllDiff(const std::vector<Index> keys, std::vector<Domain>& domains);

    /// Partially apply known values
    virtual Constraint::shared_ptr partiallyApply(
        const Values& values) const;

    /// Partially apply known values, domain version
    virtual Constraint::shared_ptr partiallyApply(
        const std::vector<Domain>& domains) const;
  };

} // namespace gtsam