GMSH - No physical group found

General
1

Hey there.

I am trying to generate a semicircular mesh with GMSH. The code to generate this semicircular mesh (.py) is shown:

import gmsh
from math import pi, cos, sin

gmsh.initialize()
gdim = 2

R = 0.1  
m0 = 0.0025

p_center = gmsh.model.geo.addPoint(0, 0, 0, m0)
num_points = 100  # Points in the circumference
angle_increment = pi / (num_points - 1)  

points = [p_center] 
for i in range(num_points):
    angle = i * angle_increment
    x = R * cos(angle)
    y = R * sin(angle)
    points.append(gmsh.model.geo.addPoint(x, y, 0, m0))

lines = []
for i in range(len(points) - 1):
    lines.append(gmsh.model.geo.addLine(points[i], points[i + 1]))

lines.append(gmsh.model.geo.addLine(points[-1], points[0]))

semicircle_loop = gmsh.model.geo.addCurveLoop(lines)

surface = gmsh.model.geo.addPlaneSurface([semicircle_loop])

domain_id = 1
gmsh.model.addPhysicalGroup(gdim, [surface], domain_id)
gmsh.model.setPhysicalName(gdim, domain_id, "domain")

gmsh.model.addPhysicalGroup(gdim - 1, [semicircle_loop], domain_id)
gmsh.model.setPhysicalName(gdim - 1, domain_id, "surface")

gmsh.model.geo.synchronize()

gmsh.model.mesh.generate(gdim)
gmsh.write("malla_semircircular.msh")

gmsh.fltk.run()
gmsh.finalize()

When I try to use this mesh in a specific simulation, I get:

No physical group found for the domain.
            Define the domain physical group.
                - if dim=2, the domain is a surface
                - if dim=3, the domain is a volume

Which, I believe, has to do with the fact that I have not defined a Physical Surface. I just don’t see how I should implement this Physical Surface.

Thanks in advance.

2

Sorry, this is a gmsh-related question with no interaction with dolfinx. You should ask this question to gmsh support channels.