s. Then a distribution 
   is performed
   to determine which zone must be loaded on each processor.
   Since isosurface computation doesn't require any communications, 
   useCom=0 and fast algorithm are chosen.
   
   Then, only certain zones are loaded on processor according to the 
   distribution using <span style="font-family: courier new,monospace;">C.readZones</span>. Skeleton tree is then converted to
   a partial tree, that is a tree where only loaded zones are defined.
    <span style="font-famil