PHPOffice / PhpSpreadsheet

                        $q = $q / $p;

                        $r = $r / $p;

                        // Row modification

                        for ($j = $k; $j < $nn; ++$j) {

                            $p = $this->H[$k][$j] + $q * $this->H[$k + 1][$j];

                            if ($notlast) {

                                $p = $p + $r * $this->H[$k + 2][$j];

                                $this->H[$k + 2][$j] = $this->H[$k + 2][$j] - $p * $z;

                            }

                            $this->H[$k][$j] = $this->H[$k][$j] - $p * $x;

                            $this->H[$k + 1][$j] = $this->H[$k + 1][$j] - $p * $y;

                        }

                        // Column modification

                        for ($i = 0; $i <= min($n, $k + 3); ++$i) {

                            $p = $x * $this->H[$i][$k] + $y * $this->H[$i][$k + 1];

                            $this->H[$k + 1][$j] = $this->H[$k + 1][$j] - $p * $y;

                        }

                        // Column modification

                        for ($i = 0; $i <= min($n, $k + 3); ++$i) {

                            $p = $x * $this->H[$i][$k] + $y * $this->H[$i][$k + 1];

                            if ($notlast) {

                                $p = $p + $z * $this->H[$i][$k + 2];

                                $this->H[$i][$k + 2] = $this->H[$i][$k + 2] - $p * $r;

                            }

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

                            $this->H[$i][$k + 1] = $this->H[$i][$k + 1] - $p * $q;

                        }

                        // Accumulate transformations

                        for ($i = $low; $i <= $high; ++$i) {

                            $p = $x * $this->V[$i][$k] + $y * $this->V[$i][$k + 1];

                            $this->H[$i][$k + 1] = $this->H[$i][$k + 1] - $p * $q;

                        }

                        // Accumulate transformations

                        for ($i = $low; $i <= $high; ++$i) {

                            $p = $x * $this->V[$i][$k] + $y * $this->V[$i][$k + 1];

                            if ($notlast) {

                                $p = $p + $z * $this->V[$i][$k + 2];

                                $this->V[$i][$k + 2] = $this->V[$i][$k + 2] - $p * $r;

                            }

                            $this->V[$i][$k] = $this->V[$i][$k] - $p;

                            $this->V[$i][$k + 1] = $this->V[$i][$k + 1] - $p * $q;

                        }

                    }  // ($s != 0)

                }  // k loop

            }  // check convergence