[1] Univ Lyon, CNRS, ENS de Lyon, Université Claude Bernard Lyon 1, LIP UMR5668, France
[2] Université Clermont Auvergne, CNRS, Clermont Auvergne INP, Mines Saint-Etienne, LIMOS, Clermont-Ferrand,63000, France
[3] Univ. Orléans, INSA Centre Val de Loire, LIFO EA 4022, Orléans,F-45067, Cedex 2, France
[4] Univ Lyon, UCBL, CNRS, LIRIS, UMR 5205, F69622, France
[5] University of Turku, Department of Mathematics and Statistics, Turku, Finland
[6] Univ Lyon, CNRS, INSA Lyon, UCBL, Centrale Lyon, Univ Lyon 2, LIRIS, UMR5205, Villeurbanne,F-69622, France