php-ai / php-ml

                for ($i = $n - 1; $i >= 0; --$i) {

                    $w = $this->H[$i][$i] - $p;

                    $r = 0.0;

                    for ($j = $l; $j <= $n; ++$j) {

                        $r = $r + $this->H[$i][$j] * $this->H[$j][$n];

                    }

                    if ($this->e[$i] < 0.0) {

                        $z = $w;

                        // Overflow control

                        $t = abs($this->H[$i][$n]);

                        if (($eps * $t) * $t > 1) {

                            for ($j = $i; $j <= $n; ++$j) {

                                $this->H[$j][$n] = $this->H[$j][$n] / $t;

                            }

                        }

                    }

                }