[Summary view]

   1  <?php
   2  
   3  declare(strict_types=1);
   4  
   5  namespace Phpml\Classification;
   6  
   7  use Phpml\Exception\InvalidArgumentException;
   8  use Phpml\NeuralNetwork\Network\MultilayerPerceptron;
   9  
  10  class MLPClassifier extends MultilayerPerceptron implements Classifier
  11  {
  12      /**
  13       * @param mixed $target
  14       *
  15       * @throws InvalidArgumentException
  16       */
  17      public function getTargetClass($target): int
  18      {
  19          if (!in_array($target, $this->classes, true)) {
  20              throw new InvalidArgumentException(
  21                  sprintf('Target with value "%s" is not part of the accepted classes', $target)
  22              );
  23          }
  24  
  25          return array_search($target, $this->classes, true);
  26      }
  27  
  28      /**
  29       * @return mixed
  30       */
  31      protected function predictSample(array $sample)
  32      {
  33          $output = $this->setInput($sample)->getOutput();
  34  
  35          $predictedClass = null;
  36          $max = 0;
  37          foreach ($output as $class => $value) {
  38              if ($value > $max) {
  39                  $predictedClass = $class;
  40                  $max = $value;
  41              }
  42          }
  43  
  44          return $predictedClass;
  45      }
  46  
  47      /**
  48       * @param mixed $target
  49       */
  50      protected function trainSample(array $sample, $target): void
  51      {
  52          // Feed-forward.
  53          $this->setInput($sample);
  54  
  55          // Back-propagate.
  56          $this->backpropagation->backpropagate($this->getLayers(), $this->getTargetClass($target));
  57      }
  58  }