gtsam/cpp/BayesNet-inl.h

99 lines
3.3 KiB
C++

/**
* @file BayesNet-inl.h
* @brief Bayes chain template definitions
* @author Frank Dellaert
*/
#include <iostream>
#include <boost/foreach.hpp>
#include <boost/tuple/tuple.hpp>
#include <boost/assign/std/vector.hpp> // for +=
using namespace boost::assign;
#include "Ordering.h"
#include "BayesNet.h"
#include "FactorGraph-inl.h"
using namespace std;
namespace gtsam {
/* ************************************************************************* */
template<class Conditional>
void BayesNet<Conditional>::print(const string& s) const {
cout << s << ":\n";
std::string key;
BOOST_FOREACH(sharedConditional conditional,conditionals_)
conditional->print("Node[" + conditional->key() + "]");
}
/* ************************************************************************* */
template<class Conditional>
bool BayesNet<Conditional>::equals(const BayesNet& cbn, double tol) const {
if(size() != cbn.size()) return false;
return equal(conditionals_.begin(),conditionals_.end(),cbn.conditionals_.begin(),equals_star<Conditional>(tol));
}
/* ************************************************************************* */
template<class Conditional>
void BayesNet<Conditional>::push_back(const BayesNet<Conditional> bn) {
BOOST_FOREACH(sharedConditional conditional,bn.conditionals_)
push_back(conditional);
}
/* ************************************************************************* */
template<class Conditional>
void BayesNet<Conditional>::push_front(const BayesNet<Conditional> bn) {
BOOST_FOREACH(sharedConditional conditional,bn.conditionals_)
push_front(conditional);
}
/* ************************************************************************* */
template<class Conditional>
Ordering BayesNet<Conditional>::ordering() const {
Ordering ord;
BOOST_FOREACH(sharedConditional conditional,conditionals_)
ord.push_back(conditional->key());
return ord;
}
/* ************************************************************************* */
template<class Conditional>
typename BayesNet<Conditional>::sharedConditional
BayesNet<Conditional>::operator[](const std::string& key) const {
const_iterator it = find_if(conditionals_.begin(),conditionals_.end(),onKey<Conditional>(key));
if (it == conditionals_.end()) throw(invalid_argument(
"BayesNet::operator['"+key+"']: not found"));
return *it;
}
/* ************************************************************************* */
template<class Factor, class Conditional>
BayesNet<Conditional> marginals(const BayesNet<Conditional>& bn, const Ordering& keys) {
// Convert to factor graph
FactorGraph<Factor> factorGraph(bn);
// Get the keys of all variables and remove all keys we want the marginal for
Ordering ord = bn.ordering();
BOOST_FOREACH(string key, keys) ord.remove(key); // TODO: O(n*k), faster possible?
// add marginal keys at end
BOOST_FOREACH(string key, keys) ord.push_back(key);
// eliminate to get joint
BayesNet<Conditional> joint = _eliminate<Factor,Conditional>(factorGraph,ord);
// remove all integrands, P(K) = \int_I P(I|K) P(K)
size_t nrIntegrands = ord.size()-keys.size();
for(int i=0;i<nrIntegrands;i++) joint.pop_front();
// joint is now only on keys, return it
return joint;
}
/* ************************************************************************* */
} // namespace gtsam