Fix Mesh::operator=

- assign pointelements
- sometimes region names were not copied correctly
- add some basic pytests for Mesh.Copy()

libsrc/meshing/meshclass.cpp

@@ -319,17 +319,24 @@ namespace netgen
     hglob = mesh2.hglob;
     hmin = mesh2.hmin;
     maxhdomain = mesh2.maxhdomain;
+    pointelements = mesh2.pointelements;
 
     // Remap string* values to new mesh
     std::map<const string*, string*> names_map;
     for (auto fi : Range(facedecoding))
       names_map[&mesh2.facedecoding[fi].bcname] = &facedecoding[fi].bcname;
 
+    auto get_name = [&](const string *old_name) -> string* {
+      if (!old_name) return nullptr;
+      if (names_map.count(old_name)) return names_map[old_name];
+      return new string(*old_name);
+    };
+
     materials.SetSize( mesh2.materials.Size() );
     for ( int i = 0; i < mesh2.materials.Size(); i++ )
     {
       const string * old_name = mesh2.materials[i];
-      if ( old_name ) materials[i] = dimension == 2 ? names_map[old_name] : new string ( *old_name );
+      if ( old_name ) materials[i] = dimension == 2 ? get_name(old_name) : new string ( *old_name );
       else materials[i] = 0;
     }
 
@@ -337,7 +344,7 @@ namespace netgen
     for ( int i = 0; i < mesh2.bcnames.Size(); i++ )
     {
       const string * old_name = mesh2.bcnames[i];
-      if ( old_name ) bcnames[i] = dimension == 3 ? names_map[old_name] : new string ( *old_name );
+      if ( old_name ) bcnames[i] = dimension == 3 ? get_name(old_name) : new string ( *old_name );
       else bcnames[i] = 0;
     }
 

tests/pytest/test_meshclass.py

@@ -1,16 +1,19 @@
 import pyngcore
 import netgen
+import pytest
+import tempfile
 
 from meshes import unit_mesh_3d
 
+
 def test_element_arrays(unit_mesh_3d):
     mesh = unit_mesh_3d
-    el0 = mesh.Elements0D()
     el1 = mesh.Elements1D()
     el2 = mesh.Elements2D()
     el3 = mesh.Elements3D()
     p = mesh.Points()
 
+    assert len(el1) > 0
     assert len(el2) > 0
     assert len(el3) > 0
     assert len(p) > 0
@@ -20,3 +23,43 @@ def test_element_arrays(unit_mesh_3d):
 
     for el in el3:
         assert len(el.vertices) == 4
+
+
+def test_copy_mesh():
+    pytest.importorskip("netgen.occ")
+    import netgen.occ as occ
+
+    box1 = occ.Box((0, 0, 0), (1, 1, 1))
+    box2 = occ.Box((1, 0, 0), (2, 1, 1))
+    box1.faces.name = "bnd1"
+    box1.name = "mat1"
+    box2.faces.name = "bnd2"
+    box2.name = "mat1"
+
+    geo = occ.OCCGeometry(occ.Glue([box1, box2]))
+    m3d = geo.GenerateMesh(maxh=99)
+
+    plane1 = occ.WorkPlane(occ.Axes((0, 0, 0), occ.X, occ.Y)).Rectangle(1, 1).Face()
+    plane1.name = "mat1"
+    plane1.edges.name = "bnd1"
+
+    plane2 = occ.WorkPlane(occ.Axes((0, 0, 0), occ.X, occ.Y)).Rectangle(2, 2).Face()
+    plane2.name = "mat2"
+    plane2.edges.name = "bnd2"
+
+    geo2 = occ.OCCGeometry(occ.Glue([plane1, plane2]), dim=2)
+    m2d = geo2.GenerateMesh(maxh=99)
+
+    for mesh in [m2d, m3d]:
+        copy = mesh.Copy()
+
+        assert copy.dim == mesh.dim
+        assert len(copy.Elements0D()) == len(mesh.Elements0D())
+        assert len(copy.Elements1D()) == len(mesh.Elements1D())
+        assert len(copy.Elements2D()) == len(mesh.Elements2D())
+        assert len(copy.Elements3D()) == len(mesh.Elements3D())
+        assert copy.GetNDomains() == mesh.GetNDomains()
+        assert copy.GetNFaceDescriptors() == mesh.GetNFaceDescriptors()
+        for dim in range(1, mesh.dim + 1):
+            assert copy.GetRegionNames(dim) == mesh.GetRegionNames(dim)
+        assert copy.GetIdentifications() == mesh.GetIdentifications()