Source: dolfin Version: 2019.2.0~legacy20240219.1c52e83-11 Followup-For: Bug #1088865
The mesh itself seems to be fine. >From Francesco's example, both python 3.12 and 3.12 give >>> mesh.cells() array([[0, 1, 4], [0, 3, 4], [1, 2, 5], [1, 4, 5], [3, 4, 7], [3, 6, 7], [4, 5, 8], [4, 7, 8]], dtype=uint32) That suggests the problem is in the high level cells() function (distinct from the cells() method in mesh).