[Summary view]

   1  <?php
   2  
   3  declare(strict_types=1);
   4  
   5  namespace Phpml\SupportVectorMachine;
   6  
   7  use Phpml\Exception\InvalidArgumentException;
   8  
   9  class DataTransformer
  10  {
  11      public static function trainingSet(array $samples, array $labels, bool $targets = false): string
  12      {
  13          $set = '';
  14          $numericLabels = [];
  15  
  16          if (!$targets) {
  17              $numericLabels = self::numericLabels($labels);
  18          }
  19  
  20          foreach ($labels as $index => $label) {
  21              $set .= sprintf('%s %s %s', ($targets ? $label : $numericLabels[$label]), self::sampleRow($samples[$index]), PHP_EOL);
  22          }
  23  
  24          return $set;
  25      }
  26  
  27      public static function testSet(array $samples): string
  28      {
  29          if (count($samples) === 0) {
  30              throw new InvalidArgumentException('The array has zero elements');
  31          }
  32  
  33          if (!is_array($samples[0])) {
  34              $samples = [$samples];
  35          }
  36  
  37          $set = '';
  38          foreach ($samples as $sample) {
  39              $set .= sprintf('0 %s %s', self::sampleRow($sample), PHP_EOL);
  40          }
  41  
  42          return $set;
  43      }
  44  
  45      public static function predictions(string $rawPredictions, array $labels): array
  46      {
  47          $numericLabels = self::numericLabels($labels);
  48          $results = [];
  49          foreach (explode(PHP_EOL, $rawPredictions) as $result) {
  50              if (isset($result[0])) {
  51                  $results[] = array_search((int) $result, $numericLabels, true);
  52              }
  53          }
  54  
  55          return $results;
  56      }
  57  
  58      public static function probabilities(string $rawPredictions, array $labels): array
  59      {
  60          $numericLabels = self::numericLabels($labels);
  61  
  62          $predictions = explode(PHP_EOL, trim($rawPredictions));
  63  
  64          $header = array_shift($predictions);
  65          $headerColumns = explode(' ', (string) $header);
  66          array_shift($headerColumns);
  67  
  68          $columnLabels = [];
  69          foreach ($headerColumns as $numericLabel) {
  70              $columnLabels[] = array_search((int) $numericLabel, $numericLabels, true);
  71          }
  72  
  73          $results = [];
  74          foreach ($predictions as $rawResult) {
  75              $probabilities = explode(' ', $rawResult);
  76              array_shift($probabilities);
  77  
  78              $result = [];
  79              foreach ($probabilities as $i => $prob) {
  80                  $result[$columnLabels[$i]] = (float) $prob;
  81              }
  82  
  83              $results[] = $result;
  84          }
  85  
  86          return $results;
  87      }
  88  
  89      public static function numericLabels(array $labels): array
  90      {
  91          $numericLabels = [];
  92          foreach ($labels as $label) {
  93              if (isset($numericLabels[$label])) {
  94                  continue;
  95              }
  96  
  97              $numericLabels[$label] = count($numericLabels);
  98          }
  99  
 100          return $numericLabels;
 101      }
 102  
 103      private static function sampleRow(array $sample): string
 104      {
 105          $row = [];
 106          foreach ($sample as $index => $feature) {
 107              $row[] = sprintf('%s:%F', $index + 1, $feature);
 108          }
 109  
 110          return implode(' ', $row);
 111      }
 112  }