Hi,

I am trying to test FreeFem parallel (combined with PETSc) by solving the following linear elastic problem:

- a 2D truss is clamped at the left end and loaded at the right end with a surface force pointing downwards.
- the geometry is constructed as follows:

```
// Domain of admissible shapes: mesh parameters
real L=2.; // length [m]
real H=1.; // height [m]
int nel=80; // mesh density
/* Domain Mesh */
mesh Dh;
int Tn0=0; // label denoting the free part of the boundary
int Tn1=1; // label denoting the loaded part of the boundary
int Td0=10; // label denoting the fixed part of the boundary
if (!mpirank) {
if (verbosity) cout<<" Domain Mesh Generation"<<endl;
Dh=square(int(L)*nel, int(H)*nel, [L*x,H*y], flags=1);
{ func nlabel=(y<1.e+2)? Tn0: label; Dh=change(Dh, flabel=nlabel);}
{ func nlabel=(x<1.e-5)? Td0: label; Dh=change(Dh, flabel=nlabel);}
{ func nlabel=(x>(L-1.e-5) && y>(H/2-H*0.05) && y<(H/2+H*0.05))? Tn1: label;
Dh=change(Dh, flabel=nlabel);}
}
broadcast(processor(0), Dh);
meshN DhG=Dh; // global mesh
int[int] n2o;
macro DhN2O() n2o // EOM // keep local to global correspondance in buildDmesh
buildDmesh(Dh); // domain decomposition
```

As I solve the problem using 4 nodes, I get the following message:

```
Elasticity problem
Warning: -- Your set of boundary condition is incompatible with the mesh label.
Warning: -- Your set of boundary condition is incompatible with the mesh label.
Warning: -- Your set of boundary condition is incompatible with the mesh label.
--- system solved with PETSc (in 2.025411e+00)
```

When I look at Dh in Paraview for example, I see that Tn1 is only existing in one of the 4 subdomainsâ€¦ hence 3 warning messages.

The problem may come from the ways labels are propagated in buildDmeshâ€¦ I would be grateful if you could you help me correct the domain decomposition part such that this error disappears. If needed, I can provide the full code (176 lines).

Thank you in advance.