Setting margin to zero throws error on meshing

[dot-cross]

If margin is set to zero the meshing fails. Tested in the palace_demo_microstrip notebook, the error is:

---

Exception Traceback (most recent call last)
/tmp/ipykernel_38063/362282738.py in ?()
1 # Generate mesh (presets: "coarse", "default", "fine")
----> 2 sim.mesh(preset="default", margin=0)

~/gsim/src/gsim/palace/driven.py in ?(self, preset, refined_mesh_size, max_mesh_size, margin, air_above, fmax, show_gui, model_name, verbose)
612 # Extract ports
613 palace_ports = extract_ports(component, stack)
614
615 # Generate mesh (config is written separately by simulate() or write_config())
--> 616 return self._generate_mesh_internal(
617 output_dir=output_dir,
618 mesh_config=mesh_config,
619 ports=palace_ports,

~/gsim/src/gsim/palace/driven.py in ?(self, output_dir, mesh_config, ports, driven_config, model_name, verbose, write_config)
422
423 if verbose:
424 logger.info("Generating mesh in %s", output_dir)
425
--> 426 mesh_result = generate_mesh(
427 component=component,
428 stack=stack,
429 ports=ports,

~/gsim/src/gsim/palace/mesh/pipeline.py in ?(component, stack, ports, output_dir, config, model_name, driven_config, write_config)
179
180 output_dir = Path(output_dir)
181
182 # Use new generator
--> 183 result = gen_mesh(
184 component=component,
185 stack=stack,
186 ports=ports,

~/gsim/src/gsim/palace/mesh/generator.py in ?(component, stack, ports, output_dir, model_name, refined_mesh_size, max_mesh_size, margin, air_margin, fmax, show_gui, driven_config, write_config)
256 )
257
258 finally:
259 gmsh.clear()
--> 260 gmsh.finalize()
261
262 # Build result (store groups for deferred config generation)
263 result = MeshResult(

~/gsim/.venv/lib/python3.12/site-packages/gmsh.py in ?(dim)
2185 lib.gmshModelMeshGenerate(
2186 c_int(dim),
2187 byref(ierr))
2188 if ierr.value != 0:
-> 2189 raise Exception(logger.getLastError())

Exception: PLC Error: A segment and a facet intersect at point

[mdmaas]

This could be related that we have both "air" and "airbox" volumes.

[dot-cross]

This is solved for the meshing stage, but now Palace fails. It happens when using lumped ports and the margin is smaller that the length of port outside the board. The error is the well known associative table error:

_____________ _______ _____ __ \____ __ /____ ____________ ____ /_/ / __ / / __ ` / / _
___ _____/ // / / // / // /
// _,//_,/__/

--> Warning!
Output folder is not empty; program will overwrite content! (output/palace)
Git changeset ID: v0.16.0-34-gea2e7b23
Running with 1 MPI process, 1 OpenMP thread
Device configuration: omp,cpu
Memory configuration: host-std
libCEED backend: /cpu/self/xsmm/blocked

MFEM abort: (r,c,f) = (1319,1699,7275)
... in function: int mfem::STable3D::operator()(int, int, int) const
... in file: /opt/palace-build/extern/mfem/general/stable3d.cpp:112`

[mdmaas]

I think this was solver with some recent PR, right? Now we can use zero margin in any dimension and set waveports or lumped ports, as long as they are inside the simulation domain.

[dot-cross]

I think this was solver with some recent PR, right? Now we can use zero margin in any dimension and set waveports or lumped ports, as long as they are inside the simulation domain.

Yes, we can consider it solved