/*
* Transform an observed ProbabilityVariable into a ProbabilityFunction
* to handle the case where the query involves an observed variable.
*/
private ProbabilityFunction transform_to_probability_function(
BayesNet bn, ProbabilityVariable pv) {
ProbabilityFunction pf = new ProbabilityFunction(bn, 1, pv.number_values(), null);
pf.set_variable(0, pv);
int index_of_value = pv.get_observed_index();
pf.set_value(index_of_value, 1.0);
return (pf);
}
/**
* Constructor for BucketTree. Does the whole initialization; it should be the only method that
* deals with symbolic names for variables.
*/
public BucketTree(Ordering ord, boolean dpc) {
int i, j, markers[];
ProbabilityFunction pf;
ProbabilityVariable pv;
DiscreteVariable aux_pv;
DiscreteFunction ut;
String order[];
do_produce_clusters = dpc;
ordering = ord;
// Collect information from the Ordering object.
bn = ord.bn;
explanation_status = ord.explanation_status;
order = ord.order;
// Indicate the first bucket to process
active_bucket = 0;
// Check the possibility that the query has an observed variable
i = bn.index_of_variable(order[order.length - 1]);
pv = bn.get_probability_variable(i);
if (pv.is_observed() == true) {
pf = transform_to_probability_function(bn, pv);
bucket_tree = new Bucket[1];
bucket_tree[0] = new Bucket(this, pv, do_produce_clusters);
insert(pf);
} else {
// Initialize the bucket objects
bucket_tree = new Bucket[order.length];
for (i = 0; i < order.length; i++) {
j = bn.index_of_variable(order[i]);
bucket_tree[i] = new Bucket(this, bn.get_probability_variable(j), do_produce_clusters);
}
// Insert the probability functions into the bucket_tree;
// first mark all functions that are actually going
// into the bucket_tree.
markers = new int[bn.number_variables()];
for (i = 0; i < order.length; i++) markers[bn.index_of_variable(order[i])] = 1;
// Now insert functions that are marked and non-null.
for (i = 0; i < bn.number_probability_functions(); i++) {
if (markers[bn.get_probability_function(i).get_index(0)] == 1) {
pf = check_evidence(bn.get_probability_function(i));
if (pf != null) {
aux_pv = (bn.get_probability_function(i)).get_variable(0);
insert(pf, !pf.memberOf(aux_pv.get_index()));
}
}
}
// Insert the utility_function.
ut = bn.get_utility_function();
if (ut != null) insert(ut);
}
}