public function testGuess()
{
$schema = new Schema();
$schema->addField('rooms')->addField('area');
$dataset = new KNN(3, $schema);
$dataset->add(new DistanceNode(array('rooms' => 1, 'area' => 350, 'type' => 'apartment')));
$dataset->add(new DistanceNode(array('rooms' => 2, 'area' => 300, 'type' => 'apartment')));
$dataset->add(new DistanceNode(array('rooms' => 3, 'area' => 300, 'type' => 'apartment')));
$dataset->add(new DistanceNode(array('rooms' => 4, 'area' => 250, 'type' => 'apartment')));
$dataset->add(new DistanceNode(array('rooms' => 7, 'area' => 850, 'type' => 'house')));
$dataset->add(new DistanceNode(array('rooms' => 7, 'area' => 900, 'type' => 'house')));
$dataset->add(new DistanceNode(array('rooms' => 7, 'area' => 1200, 'type' => 'house')));
$dataset->add(new DistanceNode(array('rooms' => 8, 'area' => 1500, 'type' => 'house')));
$dataset->add(new DistanceNode(array('rooms' => 1, 'area' => 800, 'type' => 'flat')));
$dataset->add(new DistanceNode(array('rooms' => 3, 'area' => 900, 'type' => 'flat')));
$dataset->add(new DistanceNode(array('rooms' => 2, 'area' => 700, 'type' => 'flat')));
$dataset->add(new DistanceNode(array('rooms' => 1, 'area' => 900, 'type' => 'flat')));
$this->assertEquals('flat', $dataset->guess(new DistanceNode(array('rooms' => 4, 'area' => 900)), 'type'));
$this->assertEquals('house', $dataset->guess(new DistanceNode(array('rooms' => 7, 'area' => 900)), 'type'));
$this->assertEquals('apartment', $dataset->guess(new DistanceNode(array('rooms' => 1, 'area' => 200)), 'type'));
}
/**
* Calculates distances
*
* @param DistanceNode $node
*/
protected function calculateDistances(DistanceNode $node)
{
$ranges = $this->calculateRanges();
foreach ($this->nodes as $neighbor) {
$deltas = array();
foreach ($this->schema->getFields() as $field) {
$range = $ranges[$field];
$delta = $neighbor->getField($field) - $node->getField($field);
$delta = $delta / $range;
$deltas[$field] = $delta;
}
$total = 0;
foreach ($deltas as $delta) {
$total += $delta * $delta;
}
$neighbor->setDistance(sqrt($total));
}
}