82 (2*(*devel_psi_un[1])(nz_un-1, 0, 0, 0)+
83 2*(*devel_psi_deux[1])(nz_deux-1, 0, 0, 0)+
84 (*devel_n_deux[1])(nz_deux-1, 0, 0, 0) +
85 (*devel_n_un[1])(nz_un-1, 0, 0, 0))
86 / fabs ((*devel_n_deux[1])(nz_deux-1, 0, 0, 0) +
87 (*devel_n_un[1])(nz_un-1, 0, 0, 0)) ;