MCordingley\Regression\Observations::getFeatures PHP Метод

    public function getFeatures() : array
    {
        return array_map(function (Observation $observation) {
            return $observation->getFeatures();
        }, $this->observations);
    }

 /**
  * Calculates the standard error of each of the regression coefficients.
  *
  * @return array
  */
 public function getStandardErrorCoefficients() : array
 {
     if (is_null($this->SCoefficients)) {
         $design = new Matrix($this->observations->getFeatures());
         $inverted = $design->transpose()->multiplyMatrix($design)->inverse();
         $diagonalVector = [];
         for ($i = 0, $size = $inverted->getRowCount(); $i < $size; $i++) {
             $diagonalVector[] = $inverted->get($i, $i);
         }
         $this->SCoefficients = (new Matrix([$diagonalVector]))->multiplyScalar($this->getMeanSquaredError())->map(function ($element) {
             return sqrt($element);
         })->toArray()[0];
     }
     return $this->SCoefficients;
 }