//  on calcule la solution par une methode de pt fixe
//
function U = cal_sol_ptfixe(cal_Melm,gradP,U)
//
//
    eps = .0001; h = .01; imax = 50;

    U0 = cal_sol_lin(cal_Melm,gradP,U);

   i = 0;
   while norm(U-U0) >= eps & i <= imax
         i = i + 1;
         U0 = U;
         U = cal_sol_lin(cal_Melm,gradP,U0);

         trace_u_1D(U,1);
         fprintf(%io(2),'i = %3i ; ||U-U0|| = %f',i,norm(U-U0));

   end;


endfunction
