| public static errorFunction ( number $x ) : number | ||
| $x | number | |
| Результат | number | |
public static function errorFunction($x)
{
if ($x == 0) {
return 0;
}
$p = 0.3275911;
$t = 1 / (1 + $p * abs($x));
$a₁ = 0.254829592;
$a₂ = -0.284496736;
$a₃ = 1.421413741;
$a₄ = -1.453152027;
$a₅ = 1.061405429;
$error = 1 - ($a₁ * $t + $a₂ * $t ** 2 + $a₃ * $t ** 3 + $a₄ * $t ** 4 + $a₅ * $t ** 5) * exp(-abs($x) ** 2);
return $x > 0 ? $error : -$error;
}