1. CIRAD, UMR AMAP, 97410 St Pierre, Réunion Island, France
2. AMAP, Univ Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France
3. Department of Mathematics and Applied Mathematics, University of Pretoria, Pretoria, South Africa
4. INRIA, équipe Mimesis, Université de Strasbourg, Icube, 1 Place de l’Hôpital, Strasbourg, France