MCordingley\Regression\Algorithm\GradientDescent\Gradient\Linear::cost PHP Метод

    public function cost(array $coefficients, array $features, float $outcome) : float
    {
        return (double) pow(abs($this->predicted($coefficients, $features) - $outcome), $this->power);
    }

 public function testCost()
 {
     $gradient = new Linear(2);
     static::assertEquals(1.0, $gradient->cost([1.0], [2.0], 3.0));
 }