PHPOffice / PhpSpreadsheet

                        $t = $this->s[$k];

                        $this->s[$k] = $this->s[$k + 1];

                        $this->s[$k + 1] = $t;

                        if ($wantv and ($k < $this->n - 1)) {

                            for ($i = 0; $i < $this->n; ++$i) {

                                $t = $this->V[$i][$k + 1];

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

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

                            }

                        }

                        if ($wantu and ($k < $this->m - 1)) {

                            for ($i = 0; $i < $this->m; ++$i) {

                                $t = $this->U[$i][$k + 1];

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

                            }

                        }

                        if ($wantu and ($k < $this->m - 1)) {

                            for ($i = 0; $i < $this->m; ++$i) {

                                $t = $this->U[$i][$k + 1];

                                $this->U[$i][$k + 1] = $this->U[$i][$k];

                                $this->U[$i][$k] = $t;

                            }

                        }

                        ++$k;

                    }

                    $iter = 0;