Apply max_volume to the default phases in 2D

CHANGELOG.rst

@@ -97,7 +97,10 @@ Fixed
 - 3D ``mesh_max_volume`` and per-phase ``max_volume`` are now honored by
   TetGen. In 2D, a per-phase ``max_volume`` larger than the global value is
   no longer capped, and an infinite ``mesh_max_volume`` is no longer passed
-  to Triangle as the (mis-parsed) switch ``ainf``.
+  to Triangle as the (mis-parsed) switch ``ainf``. The ``max_volume`` of a
+  phase replaces the global value for that phase, an infinite one included,
+  and phases without one, such as the default phases when none are given,
+  use the global value.
 - ``Ellipsoid.approximate`` mapped the axes incorrectly for the ordering
   c >= a >= b, so those grains were tessellated with the wrong orientation.
   The b >= c >= a ordering is now sorted explicitly as well.

docs/source/sphinx_gallery/plot_demos.py

@@ -24,7 +24,7 @@
 # them is edited, and the build would serve stale figures.
 #
 # Managed by docs/example_digest.py. Do not edit by hand.
-EXAMPLES_DIGEST = '2d39355b71ddd257'
+EXAMPLES_DIGEST = '22bb4ed7ea2ddd9f'
 
 example_dir = '../../../src/microstructpy/examples'
 

src/microstructpy/meshing/trimesh.py

@@ -217,8 +217,8 @@ def from_polymesh(cls, polymesh, phases=None, mesher='Triangle/Tetgen',
             polymesh (PolyMesh): A polygon/polyhedron mesh.
             phases (list): *(optional)* A list of dictionaries containing
                 options for each phase.
-                Default is
-                ``{'material_type': 'solid', 'max_volume': float('inf')}``.
+                Default is ``{'material_type': 'solid'}`` for each phase,
+                meshed with the ``max_volume`` argument.
             mesher (str): {'Triangle/TetGen' | 'Triangle'  | 'TetGen' | 'gmsh'}
                 specify the mesh generator. Default is 'Triangle/TetGen'.
             min_angle (float): The minimum interior angle, in degrees, of an
@@ -844,8 +844,7 @@ def from_polymesh(cls, polymesh, mesh_size, phases=None):
             mesh_size (float): The side length of each pixel/voxel.
             phases (list): *(optional)* A list of dictionaries containing
                 options for each phase.
-                Default is
-                ``{'material_type': 'solid', 'max_volume': float('inf')}``.
+                Default is ``{'material_type': 'solid'}`` for each phase.
 
         """
         if phases is None:
@@ -1965,10 +1964,13 @@ def _amorphous_seed_numbers(pmesh, phases):
 
 
 def _default_phases(polymesh):
-    """Default phases: one solid phase per phase number of the polymesh."""
+    """Default phases: one solid phase per phase number of the polymesh.
+
+    They have no ``max_volume``, so the ``max_volume`` argument of the
+    mesher applies to their regions.
+    """
     n_phases = int(np.max(polymesh.phase_numbers)) + 1
-    return [{'material_type': 'solid', 'max_volume': float('inf')}
-            for _ in range(n_phases)]
+    return [{'material_type': 'solid'} for _ in range(n_phases)]
 
 
 def _pt3d(pt):

tests/meshing/test_trimesh_fixes.py

@@ -342,6 +342,19 @@ def test_triangle_per_phase_max_volume_exceeds_global(case_2d):
     assert np.all(areas[elem_phases != 0] <= 1e-3 + 1e-9)
 
 
+@pytest.mark.parametrize('periodic', [False, True])
+def test_triangle_max_volume_without_phases(periodic):
+    # Without phases, the max_volume argument limits the area of the
+    # triangles. The default phases must not carry a limit of their own,
+    # which would replace it (an infinite one left it unapplied).
+    domain = msp.geometry.Square(side_length=4, corner=(0, 0))
+    seeds = msp.seeding.SeedList([msp.seeding.Seed.factory(
+        'circle', r=1.5, position=(2.2, 1.9))])
+    pmesh = msp.meshing.PolyMesh.from_seeds(seeds, domain, periodic=periodic)
+    mesh = TriMesh.from_polymesh(pmesh, min_angle=20, max_volume=0.4)
+    assert np.max(simplex_volumes(mesh)) <= 0.4 + 1e-9
+
+
 def test_triangle_infinite_max_volume_not_passed(case_2d, monkeypatch):
     pmesh, phases, _ = case_2d
     captured = {}