Issue with boundary conditions on a basic example

Hi all,

I have a warning I don’t understand about my boundary conditions:
Warning: – Your set of boundary condition is incompatible with the mesh label.

The basic example I’m testing is the following:

border a(t=0, dims[0]){x=t; y=0; label=1;};
border b(t=0, dims[1]){x=dims[0]; y=t; label=2;};
border f(t=0, dims[0]){x=dims[0]-t; y=dims[1]; label=3;};
border d(t=0, dims[1]){x=0; y=dims[1]-t; label=4;};
n = 3;
mesh fm = buildmesh(a(n) + b(n) + f(n) + d(n));
fespace Vh(fm, P1);
func real heatsource(){
return 1;
Vh u, v;
Vh myHeat = heatsource();
problem heat(u,v) = int2d(fm)(dx(u)*dx(v) + dy(u)dy(v)) - int2d(fm)(myHeatv)
+ on(a, u=0)
+ on(b, u=0)
+ on(f, u=0)
+ on(d, u=0);

Do you have any idea which mistake did I do ?


+ on(a, u=0)
+ on(b, u=0)
+ on(f, u=0)
+ on(d, u=0);

should read

+ on(1, u=0)
+ on(2, u=0)
+ on(3, u=0)
+ on(4, u=0);

Indeed, no warning anymore, thanks a lot :slight_smile: