[Dune] adapting grid and geometrygrid

[Marco Cisternino]

Good morning,
I'd need your help to understand how to adapt a grid with an associated 
geometry grid.
I tried to call the adapt() method for the geometrygrid, but the 
compiler tells me the method is protected.
I tried to call the adapt() method for the host grid and then call the 
update() method for the geometry grid but the update() calls adapt() for 
the geometrygrid which is protected, then same compiling error.
I read from the documentation that if I call adapt() for the host grid, 
the update() method is automatically called for the geometrygrid.
By this way the compiler doesn't complain, but I'm not sure if
Am I well understood? Is this the right way to get the adaptation of 
both the grids (geometry and host)?
If not, could anyone explain me how to adapt a geometrygrid and its host 
grid, please??
Thanks.

Marco