[1] Univ Politecn Cataluna, Dept Matemat Aplicada 3, ETS Ingenieros Caminos, E-08034 Barcelona, Spain
[2] Univ Politecn Catalunya BarcelonaTech, Lab Calcul Numer LaCaN, Barcelona 08034, Spain
[3] Univ Politecn Cataluna, Escola Engn Telecomunicacio & Aeroespacial Castel, E-08034 Barcelona, Spain