Hi all, what’s the best way to include a function of spatial variable x into the weak form? I know that freefem has x and y built in, but is it still necessary to interpolate them onto the mesh or can I simply enter them as they are? E.g:

mesh dom4;

dom4=buildmesh(…);

fespace Vh(dom4, P2);

Vh u, v;

…

Vh xx=x; **<----- is this neccessary to include a function of x in the weak form of my problem?**

problem(u,v)

=int2d(dom4)(… f(xx)… ) <---- **Here, f is just an arbitrary function.**

…

;

**OR, can I write it as follows without interpolating x onto the mesh:**

problem(u,v)

=int2d(dom4)(… f(x)… )

…

;