26 string grad_approx =
"P" + to_string(uh.get_space().degree()-1) +
"d";
27 space Xh (uh.get_geo(), grad_approx);
28 if (grad_approx ==
"P0d")
return lazy_interpolate (Xh, norm(uh));
29 space T0h (uh.get_geo(), grad_approx);
30 size_t d = uh.get_geo().dimension();
32 return lazy_interpolate (T0h, sqrt(2*norm2(D(uh)) +
lambda*sqr(div(uh))));