[1] Western Norway Univ Appl Sci, Dept Comp Math & Phys, Inndalsveien 28, N-5063 Bergen, Norway
[2] Univ Cape Town, Ctr Res Computat & Appl Mech CERECAM, ZA-7701 Rondebosch, South Africa
[3] Univ Cape Town, Dept Math & Appl Math, ZA-7701 Rondebosch, South Africa
[4] African Inst Math Sci AIMS South Africa, 6-8 Melrose Rd, ZA-7945 Muizenberg, South Africa
[5] Tech Univ Chemnitz, D-09126 Chemnitz, Germany
[6] African Inst Math Sci AIMS Senegal, Km 2,Route Joal,BP 1418, Mbour, Senegal