Computational Sciences and Engineering, Qatar Computing Research Institute, Doha, P. O. Box 5825, Qatar. m.ceccarelli@gmail.com.|Computational Sciences and Engineering, Qatar Computing Research Institute, Doha, P. O. Box 5825, Qatar. m.ceccarelli@gmail.com.|Computational Sciences and Engineering, Qatar Computing Research Institute, Doha, P. O. Box 5825, Qatar. m.ceccarelli@gmail.com.