Start of factor graph port. Things don't work yet, but a lot of syntax updates towards PHP

PHPSkills/FactorGraphs/Factor.php

@@ -0,0 +1,96 @@
+<?php
+namespace Moserware\Skills\FactorGraphs;
+
+require_once(dirname(__FILE__) . "../Guard.php");
+require_once(dirname(__FILE__) . "../HashMap.php");
+
+use Moserware\Skills\Guard;
+use Moserware\Skills\HashMap;
+
+class Factor
+{
+    private $_messages = array();
+    private $_messageToVariableBinding;
+
+    private $_name;
+    private $_variables = array();
+
+    protected function __construct($name)
+    {
+        $this->_name = "Factor[" . $name . "]";
+        $this->_messagesToVariableBinding = new HashMap();
+    }
+
+    /// Returns the log-normalization constant of that factor
+    public function getLogNormalization()
+    {
+        return 0;
+    }
+
+    /// Returns the number of messages that the factor has
+    public function getNumberOfMessages()
+    {
+        return count($this->_messages);
+    }
+
+    protected function getVariables()
+    {
+        return $this->_variables;
+    }
+
+    protected function getMessages()
+    {
+        return $this->_messages;
+    }
+
+    /// Update the message and marginal of the i-th variable that the factor is connected to
+    public function updateMessageIndex($messageIndex)
+    {
+        Guard::argumentIsValidIndex($messageIndex, count($this->_messages), "messageIndex");
+        return $this->updateMessageVariable($this->_messages[$messageIndex], $this->_messageToVariableBinding->getValue($messageIndex));
+    }
+
+    protected function updateMessageVariable($message, $variable)
+    {
+        throw new Exception();
+    }
+
+    /// Resets the marginal of the variables a factor is connected to
+    public function resetMarginals()
+    {
+        foreach ($this->_messageToVariableBindings->getAllValues() as $currentVariable)
+        {
+            $currentVariable->resetToPrior();
+        }
+    }
+
+    /// Sends the ith message to the marginal and returns the log-normalization constant
+    public function sendMessageIndex($messageIndex)
+    {
+        Guard::argumentIsValidIndex($messageIndex, count($_messages), "messageIndex");
+
+        $message = $this->_messages[$messageIndex];
+        $variable = $this->_messageToVariableBinding->getValue($message);
+        return $this->sendMessageVariable($message, $variable);
+    }
+
+    protected abstract function sendMessageVariable($message, $variable);
+
+    public abstract function createVariableToMessageBinding($variable);
+
+    protected function createVariableToMessageBinding($variable, $message)
+    {
+        $index = count($this->_messages);
+        $this->_messages[] = $message;
+        $this->_messageToVariableBinding->setValue($message) = $variable;
+        $this->_variables[] = $variable;
+        return $message;
+    }
+
+    public function __toString()
+    {
+        return ($this->_name != null) ? $this->_name : base::__toString();
+    }
+}
+
+?>