PhpSpreadsheet/samples/13_CalculationCyclicFormulae.php

<?php

use PhpOffice\PhpSpreadsheet\Calculation;
use PhpOffice\PhpSpreadsheet\Spreadsheet;

require __DIR__ . '/Header.php';

// Create new Spreadsheet object
$helper->log('Create new Spreadsheet object');
$spreadsheet = new Spreadsheet();

// Add some data, we will use some formulas here
$helper->log('Add some data and formulas');
$spreadsheet->getActiveSheet()->setCellValue('A1', '=B1')
        ->setCellValue('A2', '=B2+1')
        ->setCellValue('B1', '=A1+1')
        ->setCellValue('B2', '=A2');

Calculation::getInstance($spreadsheet)->cyclicFormulaCount = 100;

// Calculated data
$helper->log('Calculated data');
for ($row = 1; $row <= 2; ++$row) {
    for ($col = 'A'; $col != 'C'; ++$col) {
        if ((!is_null($formula = $spreadsheet->getActiveSheet()->getCell($col . $row)->getValue())) &&
                ($formula[0] == '=')) {
            echo 'Value of ', $col, $row, ' [', $formula, ']: ',
            $spreadsheet->getActiveSheet()->getCell($col . $row)->getCalculatedValue() . EOL;
        }
    }
}

// Save
$helper->write($spreadsheet, __FILE__);