/* ************************************************************************* */
std::pair<DiscreteConditional::shared_ptr, DecisionTreeFactor::shared_ptr> //
EliminateDiscrete(const DiscreteFactorGraph& factors, const Ordering& frontalKeys) {
// PRODUCT: multiply all factors
gttic(product);
DecisionTreeFactor product;
BOOST_FOREACH(const DiscreteFactor::shared_ptr& factor, factors)
product = (*factor) * product;
gttoc(product);
// sum out frontals, this is the factor on the separator
gttic(sum);
DecisionTreeFactor::shared_ptr sum = product.sum(frontalKeys);
gttoc(sum);
// Ordering keys for the conditional so that frontalKeys are really in front
Ordering orderedKeys;
orderedKeys.insert(orderedKeys.end(), frontalKeys.begin(), frontalKeys.end());
orderedKeys.insert(orderedKeys.end(), sum->keys().begin(), sum->keys().end());
// now divide product/sum to get conditional
gttic(divide);
DiscreteConditional::shared_ptr cond(new DiscreteConditional(product, *sum, orderedKeys));
gttoc(divide);
return std::make_pair(cond, sum);
}
/* ************************************************************************* */
std::pair<DiscreteConditional::shared_ptr, DecisionTreeFactor::shared_ptr> //
EliminateDiscrete(const FactorGraph<DiscreteFactor>& factors, size_t num) {
// PRODUCT: multiply all factors
gttic(product);
DecisionTreeFactor product;
BOOST_FOREACH(const DiscreteFactor::shared_ptr& factor, factors)
product = (*factor) * product;
gttoc(product);
// sum out frontals, this is the factor on the separator
gttic(sum);
DecisionTreeFactor::shared_ptr sum = product.sum(num);
gttoc(sum);
// now divide product/sum to get conditional
gttic(divide);
DiscreteConditional::shared_ptr cond(new DiscreteConditional(product, *sum));
gttoc(divide);
return std::make_pair(cond, sum);
}