[pstricks] psgrid

[Alain Matthes]

Herbert and Jean-Côme, thanks for your answers.

With Herbert's solution, I need to make some calculations, because it  
is necessary that the code is included in a macro.

The solution of Jean-Côme is more complicated but very interesting  
and teaching, but I need to study it because
I want to make some changes ( I would like that the grid is  
positioned on the axes).

Thanks again

Alain Matthes