Fatal error: Uncaught Error: Class 'Matrix' not found in /var/www/html/inc/classes/PHPExcel/Shared/JAMA/examples/LagrangeInterpolation.php:39 Stack trace: #0 /var/www/html/inc/classes/PHPExcel/Shared/JAMA/examples/LagrangeInterpolation.php(54): LagrangeInterpolation->findPolynomialFactors(Array, Array) #1 {main} thrown in /var/www/html/inc/classes/PHPExcel/Shared/JAMA/examples/LagrangeInterpolation.php on line 39