public static boolean are_d_connected(AbstractVariable x1, AbstractVariable x2, Vector evidence)
throws RemoteException {
// Find all paths between x1 and x2, then see if there is some path which is
// d-connecting given the evidence. If so, return true, otherwise false.
Hashtable path_sets = new Hashtable(); // HEY !!! THIS OUGHT TO BE CACHED SOMEWHERE !!!
PathAnalysis.compile_paths(x1, x2, path_sets);
Vector path_set = (Vector) path_sets.get(new VariablePair(x1, x2));
if (path_set == null)
// No connections whatsoever.
return false;
Enumeration path_set_enum = path_set.elements();
while (path_set_enum.hasMoreElements()) {
AbstractVariable[] path = (AbstractVariable[]) path_set_enum.nextElement();
if (is_d_connecting(path, evidence)) {
System.err.print("PathAnalysis.are_d_connected: path ");
int i;
for (i = 0; i < path.length; i++) System.err.print(path[i].get_name() + " ");
System.err.print("is d-connected given evidence ");
for (i = 0; i < evidence.size(); i++)
System.err.print(((AbstractVariable) evidence.elementAt(i)).get_name() + " ");
System.err.println("");
return true;
}
}
return false;
}
public String toString() {
String s = "[" + helper_type + ";";
for (Enumeration e = seq.elements(); e.hasMoreElements(); ) {
try {
Class c = (Class) e.nextElement();
s += c.getName() + ",";
} catch (NoSuchElementException ee) {
s += "???" + ",";
}
}
return s + "]";
}
public static void find_all_paths(
AbstractVariable x, AbstractVariable end, Vector path_set, Stack path_stack)
throws RemoteException {
int i;
path_stack.push(x);
if (x == end) {
// Construct a path from the beginning to the end, using what's on the stack.
AbstractVariable[] path = new AbstractVariable[path_stack.size()];
// System.err.println( "\tFound path: " );
Enumeration e;
for (i = 0, e = path_stack.elements(); e.hasMoreElements(); i++) {
path[i] = (AbstractVariable) e.nextElement();
// System.err.print( path[i].get_name()+" " );
}
// System.err.println("");
path_set.addElement(path);
path_stack.pop();
return;
}
AbstractVariable[] parents = x.get_parents();
for (i = 0; i < parents.length; i++) {
Enumeration e = path_stack.elements();
boolean is_on_stack = false;
while (e.hasMoreElements())
if (e.nextElement() == parents[i]) {
is_on_stack = true;
break;
}
if (!is_on_stack) find_all_paths(parents[i], end, path_set, path_stack);
}
AbstractVariable[] children = x.get_children();
for (i = 0; i < children.length; i++) {
Enumeration e = path_stack.elements();
boolean is_on_stack = false;
while (e.hasMoreElements())
if (e.nextElement() == children[i]) {
is_on_stack = true;
break;
}
if (!is_on_stack) find_all_paths(children[i], end, path_set, path_stack);
}
path_stack.pop();
}
public boolean equals(Object another) {
if (another instanceof HelperCacheKey) {
HelperCacheKey another_key = (HelperCacheKey) another;
if (!this.helper_type.equals(another_key.helper_type)) return false;
Enumeration e1, e2;
for (e1 = this.seq.elements(), e2 = another_key.seq.elements(); e1.hasMoreElements(); ) {
Object o1, o2;
try {
o1 = e1.nextElement();
} catch (NoSuchElementException ex) {
throw new RuntimeException("HelperCacheKey.equals: should never happen, " + ex);
}
try {
o2 = e2.nextElement();
} catch (NoSuchElementException ex) {
return false;
} // e2 has fewer elements than e2, no match
if (!o1.equals(o2)) return false;
}
if (e2.hasMoreElements()) return false;
else return true;
} else return false;
}
/**
* Check the helpers currently stored in the helper cache to see if any of them can handle the
* sequence we've just been given. This avoids pinging the belief network context to get a helper
* list.
*/
public static Class find_helper_class1(
Vector seq, String helper_type, int[] max_class_score, int[] max_count_score)
throws ClassNotFoundException {
int[] class_score1 = new int[1], count_score1 = new int[1];
max_class_score[0] = -1;
max_count_score[0] = -1;
Class cmax_score = null;
for (Enumeration e = helper_cache.keys(); e.hasMoreElements(); ) {
try {
HelperCacheKey key = (HelperCacheKey) e.nextElement();
if (!key.helper_type.equals(helper_type)) continue;
Class c = (Class) helper_cache.get(key);
SeqTriple[] sm = (SeqTriple[]) invoke_description(c);
if (sm == null) continue; // apparently not a helper class
if (MatchClassPattern.matches(sm, seq, class_score1, count_score1)) {
if (class_score1[0] > max_class_score[0]
|| (class_score1[0] == max_class_score[0] && count_score1[0] > max_count_score[0])) {
cmax_score = c;
max_class_score[0] = class_score1[0];
max_count_score[0] = count_score1[0];
}
}
} catch (Exception e2) {
} // eat it; stagger forward
}
if (Global.debug > 1)
System.err.println(
"PiHelperLoader.find_helper_class1: helper "
+ (cmax_score == null ? "is NOT" : "is")
+ " in cache.");
if (cmax_score == null) // no luck; try to get a helper list from the bnc & plunge ahead
return find_helper_class0(seq, helper_type, max_class_score, max_count_score);
else // success!
return cmax_score;
}
/**
* Contact a belief network context, get the helper list, and search the list to see if there's a
* helper which matches the type sequence specified. If there's more than one helper which
* matches, find the ``best fit.''
*
* <p>The class and count scores of the best-fitting helper class are written into
* <tt>max_class_score[0]</tt> and <tt>max_count_score[0]</tt>, respectively.
*/
public static Class find_helper_class0(
Vector seq, String helper_type, int[] max_class_score, int[] max_count_score)
throws ClassNotFoundException {
long t0 = System.currentTimeMillis();
if (bnc != null) // make sure the reference is still alive
try {
bnc.get_name();
} catch (RemoteException e) {
bnc = null;
}
if (bnc == null) // need to locate a context
{
String cb = System.getProperty("java.rmi.server.codebase", "http://localhost");
long tt0 = System.currentTimeMillis();
try {
bnc = BeliefNetworkContext.locate_context(new URL(cb).getHost());
} catch (Exception e) {
throw new ClassNotFoundException("nested: " + e);
}
}
String[] helperlist;
try {
helperlist = bnc.get_helper_names(helper_type);
} catch (RemoteException e) {
throw new ClassNotFoundException("bnc.get_helper_names failed");
}
int[] class_score1 = new int[1], count_score1 = new int[1];
max_class_score[0] = -1;
max_count_score[0] = -1;
Class cmax_score = null;
for (int i = 0; i < helperlist.length; i++) {
try {
Class c = RMIClassLoader.loadClass(helperlist[i]);
SeqTriple[] sm = (SeqTriple[]) invoke_description(c);
if (sm == null) continue; // apparently not a helper class
if (MatchClassPattern.matches(sm, seq, class_score1, count_score1)) {
if (class_score1[0] > max_class_score[0]
|| (class_score1[0] == max_class_score[0] && count_score1[0] > max_count_score[0])) {
cmax_score = c;
max_class_score[0] = class_score1[0];
max_count_score[0] = count_score1[0];
}
}
} catch (Exception e2) {
System.err.println("PiHelperLoader: attempt to load " + helperlist[i] + " failed; " + e2);
}
}
if (cmax_score == null) {
System.err.println("find_helper_class0: failed; helper list:");
for (int i = 0; i < helperlist.length; i++) System.err.println("\t" + helperlist[i]);
String s = "";
for (Enumeration e = seq.elements(); e.hasMoreElements(); ) {
try {
Class c = (Class) e.nextElement();
s += c.getName() + ",";
} catch (NoSuchElementException ee) {
s += "???" + ",";
}
}
throw new ClassNotFoundException("no " + helper_type + " helper for sequence [" + s + "]");
}
// FOR NOW IGNORE THE POSSIBILITY OF TWO OR MORE MATCHES !!!
return cmax_score;
}
public static void main(String[] args) {
boolean do_compile_all = false;
String bn_name = "", x1_name = "", x2_name = "";
Vector evidence_names = new Vector();
for (int i = 0; i < args.length; i++) {
if (args[i].charAt(0) != '-') continue;
switch (args[i].charAt(1)) {
case 'b':
bn_name = args[++i];
break;
case 'a':
do_compile_all = true;
break;
case 'x':
if (args[i].charAt(2) == '1') x1_name = args[++i];
else if (args[i].charAt(2) == '2') x2_name = args[++i];
else System.err.println("PathAnalysis.main: " + args[i] + " -- huh???");
break;
case 'e':
evidence_names.addElement(args[++i]);
break;
default:
System.err.println("PathAnalysis.main: " + args[i] + " -- huh???");
}
}
try {
BeliefNetworkContext bnc = new BeliefNetworkContext(null);
bnc.add_path("/bechtel/users10/krarti/dodier/belief-nets/assorted");
AbstractBeliefNetwork bn = bnc.load_network(bn_name);
Hashtable path_sets;
Enumeration p;
if ((p = PathAnalysis.has_directed_cycle(bn)) == null)
System.err.println("PathAnalysis: no directed cycles found in " + bn_name);
else {
System.err.println("PathAnalysis.main: " + bn_name + " has a directed cycle; quit.");
System.err.print(" cycle is: ");
while (p.hasMoreElements()) {
System.err.print(((AbstractVariable) p.nextElement()).get_name());
if (p.hasMoreElements()) System.err.print(" -> ");
else System.err.println("");
}
System.exit(1);
}
Vector evidence = new Vector();
if (evidence_names.size() > 0) {
for (int i = 0; i < evidence_names.size(); i++)
evidence.addElement(bn.name_lookup((String) (evidence_names.elementAt(i))));
}
if (do_compile_all) {
path_sets = PathAnalysis.compile_all_paths(bn);
} else {
AbstractVariable x1 = (AbstractVariable) bn.name_lookup(x1_name);
AbstractVariable x2 = (AbstractVariable) bn.name_lookup(x2_name);
path_sets = new Hashtable();
PathAnalysis.compile_paths(x1, x2, path_sets);
if (PathAnalysis.are_d_connected(x1, x2, evidence))
System.err.print(
x1.get_name() + " and " + x2.get_name() + " are d-connected given evidence ");
else
System.err.print(
x1.get_name() + " and " + x2.get_name() + " are NOT d-connected given evidence ");
for (int i = 0; i < evidence.size(); i++)
System.err.print(((AbstractVariable) evidence.elementAt(i)).get_name() + " ");
System.err.println("");
}
System.err.println("PathAnalysis.main: results of path finding:");
AbstractVariable[] u = bn.get_variables();
for (int i = 0; i < u.length; i++) {
System.err.println(" --- paths from: " + u[i].get_name() + " ---");
for (int j = i + 1; j < u.length; j++) {
VariablePair vp = new VariablePair(u[i], u[j]);
Vector path_set = (Vector) path_sets.get(vp);
if (path_set == null) continue;
Enumeration path_set_enum = path_set.elements();
while (path_set_enum.hasMoreElements()) {
AbstractVariable[] path = (AbstractVariable[]) path_set_enum.nextElement();
System.err.print(" path: ");
for (int k = 0; k < path.length; k++) System.err.print(path[k].get_name() + " ");
System.err.println("");
}
}
}
System.exit(0);
} catch (Exception e) {
System.err.println("PathAnalysis.main:");
e.printStackTrace();
System.exit(1);
}
}