public function __construct($mean, $variance, Variable $variable)
{
parent::__construct(sprintf("Prior value going to %s", $variable));
$this->_newMessage = new GaussianDistribution($mean, sqrt($variance));
$newMessage = new Message(GaussianDistribution::fromPrecisionMean(0, 0), sprintf("message from %s to %s", $this, $variable));
$this->createVariableToMessageBindingWithMessage($variable, $newMessage);
}
public function __construct($betaSquared, Variable $variable1, Variable $variable2)
{
parent::__construct(sprintf("Likelihood of %s going to %s", $variable2, $variable1));
$this->_precision = 1.0 / $betaSquared;
$this->createVariableToMessageBinding($variable1);
$this->createVariableToMessageBinding($variable2);
}
public function __construct($epsilon, Variable &$variable)
{
parent::__construct(sprintf("%s <= %.2f", $variable, $epsilon));
$this->_epsilon = $epsilon;
$this->createVariableToMessageBinding($variable);
}
public function __construct(Variable $sumVariable, array $variablesToSum, array $variableWeights = null)
{
parent::__construct(self::createName($sumVariable, $variablesToSum, $variableWeights));
$this->_weights = array();
$this->_weightsSquared = array();
// The first weights are a straightforward copy
// v_0 = a_1*v_1 + a_2*v_2 + ... + a_n * v_n
$variableWeightsLength = count($variableWeights);
$this->_weights[0] = \array_fill(0, count($variableWeights), 0);
for ($i = 0; $i < $variableWeightsLength; $i++) {
$weight = $variableWeights[$i];
$this->_weights[0][$i] = $weight;
$this->_weightsSquared[0][$i] = square($weight);
}
$variablesToSumLength = count($variablesToSum);
// 0..n-1
$this->_variableIndexOrdersForWeights[0] = array();
for ($i = 0; $i < $variablesToSumLength + 1; $i++) {
$this->_variableIndexOrdersForWeights[0][] = $i;
}
$variableWeightsLength = count($variableWeights);
// The rest move the variables around and divide out the constant.
// For example:
// v_1 = (-a_2 / a_1) * v_2 + (-a3/a1) * v_3 + ... + (1.0 / a_1) * v_0
// By convention, we'll put the v_0 term at the end
$weightsLength = $variableWeightsLength + 1;
for ($weightsIndex = 1; $weightsIndex < $weightsLength; $weightsIndex++) {
$currentWeights = \array_fill(0, $variableWeightsLength, 0);
$variableIndices = \array_fill(0, $variableWeightsLength + 1, 0);
$variableIndices[0] = $weightsIndex;
$currentWeightsSquared = \array_fill(0, $variableWeightsLength, 0);
// keep a single variable to keep track of where we are in the array.
// This is helpful since we skip over one of the spots
$currentDestinationWeightIndex = 0;
for ($currentWeightSourceIndex = 0; $currentWeightSourceIndex < $variableWeightsLength; $currentWeightSourceIndex++) {
if ($currentWeightSourceIndex == $weightsIndex - 1) {
continue;
}
$currentWeight = -$variableWeights[$currentWeightSourceIndex] / $variableWeights[$weightsIndex - 1];
if ($variableWeights[$weightsIndex - 1] == 0) {
// HACK: Getting around division by zero
$currentWeight = 0;
}
$currentWeights[$currentDestinationWeightIndex] = $currentWeight;
$currentWeightsSquared[$currentDestinationWeightIndex] = $currentWeight * $currentWeight;
$variableIndices[$currentDestinationWeightIndex + 1] = $currentWeightSourceIndex + 1;
$currentDestinationWeightIndex++;
}
// And the final one
$finalWeight = 1.0 / $variableWeights[$weightsIndex - 1];
if ($variableWeights[$weightsIndex - 1] == 0) {
// HACK: Getting around division by zero
$finalWeight = 0;
}
$currentWeights[$currentDestinationWeightIndex] = $finalWeight;
$currentWeightsSquared[$currentDestinationWeightIndex] = square($finalWeight);
$variableIndices[count($variableWeights)] = 0;
$this->_variableIndexOrdersForWeights[] = $variableIndices;
$this->_weights[$weightsIndex] = $currentWeights;
$this->_weightsSquared[$weightsIndex] = $currentWeightsSquared;
}
$this->createVariableToMessageBinding($sumVariable);
foreach ($variablesToSum as $currentVariable) {
$localCurrentVariable = $currentVariable;
$this->createVariableToMessageBinding($localCurrentVariable);
}
}
