It gets a result... unfortunately it's wrong. But hey, that's progress :) Lots of debugging code left in to make up for a less than ideal debugger

PHPSkills/FactorGraphs/Factor.php

@@ -35,12 +35,14 @@ abstract class Factor
         return count($this->_messages);
     }
 
-    protected function &getVariables()
+    // DEBUG: make protected
+    public function &getVariables()
     {
         return $this->_variables;
     }
 
-    protected function &getMessages()
+    // DEBUG: make protected
+    public function &getMessages()
     {
         return $this->_messages;
     }
@@ -51,6 +53,11 @@ abstract class Factor
         Guard::argumentIsValidIndex($messageIndex, count($this->_messages), "messageIndex");
         $message = &$this->_messages[$messageIndex];
         $variable = &$this->_messageToVariableBinding->getValue($message);
+        // DEBUG
+        $selfName = (string)$this;
+        $debugName = (string)$variable;
+        $debugHash = \spl_object_hash($variable);
+        $debugValue = $variable->getValue();
         return $this->updateMessageVariable($message, $variable);
     }
 
@@ -86,9 +93,11 @@ abstract class Factor
     protected function &createVariableToMessageBindingWithMessage(Variable &$variable, Message &$message)
     {
         $index = count($this->_messages);
-        $this->_messages[] = &$message;
+        $localMessages = &$this->_messages;
+        $localMessages[] = &$message;
         $this->_messageToVariableBinding->setValue($message, $variable);
-        $this->_variables[] = &$variable;
+        $localVariables = &$this->_variables;
+        $localVariables[] = &$variable;
         return $message;
     }
 

PHPSkills/FactorGraphs/Message.php

@@ -20,6 +20,8 @@ class Message
 
     public function setValue(&$value)
     {
+        // DEBUG
+        $selfName = (string)$this;
         $this->_value = &$value;
     }
 

PHPSkills/FactorGraphs/Schedule.php

@@ -34,7 +34,10 @@ class ScheduleStep extends Schedule
 
     public function visit($depth = -1, $maxDepth = 0)
     {
-        $delta = $this->_factor->updateMessageIndex($this->_index);
+        $currentFactor = &$this->_factor;
+        // DEBUG
+        $currentFactorName = (string)$currentFactor;
+        $delta = $currentFactor->updateMessageIndex($this->_index);
         return $delta;
     }
 }

PHPSkills/FactorGraphs/Variable.php

@@ -17,12 +17,18 @@ class Variable
     public function &getValue()
     {
         $value = &$this->_value;
+        // DEBUG
+        $selfHash = \spl_object_hash($this);
+        $selfName = (string)$this;
         return $value;
     }
 
     public function setValue(&$value)
     {
-        $this->_value = $value;
+        // DEBUG
+        $selfName = (string)$this;        
+        $selfHash = \spl_object_hash($this);
+        $this->_value = &$value;
     }
 
     public function resetToPrior()
@@ -57,15 +63,16 @@ class DefaultVariable extends Variable
 class KeyedVariable extends Variable
 {
     private $_key;
-    public function __construct($key, $name, &$prior)
+    public function __construct(&$key, $name, &$prior)
     {
         parent::__construct($name, $prior);
-        $this->_key = $key;
+        $this->_key = &$key;
     }
 
-    public function getKey()
+    public function &getKey()
     {
-        return $this->_key;
+        $key = &$this->_key;
+        return $key;
     }
 }