The vorticity associated to a vector field
int main(
int argc,
char** argv) {
const space& Xh = uh.get_space();
string grad_approx =
"P" +
itos(Xh.degree()-1) +
"d";
string valued = (uh.get_geo().dimension() == 3) ? "vector" : "scalar";
space Lh (uh.get_geo(), grad_approx, valued);
}