DiscreteBayesNet.cpp

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/* ----------------------------------------------------------------------------
 
 * GTSAM Copyright 2010, Georgia Tech Research Corporation,
 * Atlanta, Georgia 30332-0415
 * All Rights Reserved
 * Authors: Frank Dellaert, et al. (see THANKS for the full author list)
 
 * See LICENSE for the license information
 
 * -------------------------------------------------------------------------- */
 
#include <gtsam/discrete/DiscreteBayesNet.h>
#include <gtsam/discrete/DiscreteConditional.h>
#include <gtsam/inference/FactorGraph-inst.h>
 
namespace gtsam {
 
// Instantiate base class
template class FactorGraph<DiscreteConditional>;
 
/* ************************************************************************* */
bool DiscreteBayesNet::equals(const This& bn, double tol) const {
  return Base::equals(bn, tol);
}
 
/* ************************************************************************* */
double DiscreteBayesNet::logProbability(const DiscreteValues& values) const {
  // evaluate all conditionals and add
  double result = 0.0;
  for (const DiscreteConditional::shared_ptr& conditional : *this)
    result += conditional->logProbability(values);
  return result;
}
 
/* ************************************************************************* */
double DiscreteBayesNet::evaluate(const DiscreteValues& values) const {
  // evaluate all conditionals and multiply
  double result = 1.0;
  for (const DiscreteConditional::shared_ptr& conditional : *this)
    result *= (*conditional)(values);
  return result;
}
 
/* ************************************************************************* */
DiscreteValues DiscreteBayesNet::sample() const {
  DiscreteValues result;
  return sample(result);
}
 
DiscreteValues DiscreteBayesNet::sample(DiscreteValues result) const {
  // sample each node in turn in topological sort order (parents first)
  for (auto it = std::make_reverse_iterator(end());
       it != std::make_reverse_iterator(begin()); ++it) {
    const DiscreteConditional::shared_ptr& conditional = *it;
    // Sample the conditional only if value for j not already in result
    const Key j = conditional->firstFrontalKey();
    if (result.count(j) == 0) {
      conditional->sampleInPlace(&result);
    }
  }
  return result;
}
 
/* *********************************************************************** */
std::string DiscreteBayesNet::markdown(
    const KeyFormatter& keyFormatter,
    const DiscreteFactor::Names& names) const {
  using std::endl;
  std::stringstream ss;
  ss << "`DiscreteBayesNet` of size " << size() << endl << endl;
  for (const DiscreteConditional::shared_ptr& conditional : *this)
    ss << conditional->markdown(keyFormatter, names) << endl;
  return ss.str();
}
 
/* *********************************************************************** */
std::string DiscreteBayesNet::html(const KeyFormatter& keyFormatter,
                                   const DiscreteFactor::Names& names) const {
  using std::endl;
  std::stringstream ss;
  ss << "<div><p><tt>DiscreteBayesNet</tt> of size " << size() << "</p>";
  for (const DiscreteConditional::shared_ptr& conditional : *this)
    ss << conditional->html(keyFormatter, names) << endl;
  return ss.str();
}
 
/* ************************************************************************* */
}  // namespace gtsam