PEC gradient support for Box and PolySlab geometries

tests/test_components/test_geometry.py

@@ -1298,3 +1298,136 @@ def test_cleanup_shapely_object():
     orig_polygon = shapely.Polygon(exterior_coords)
     new_polygon = cleanup_shapely_object(orig_polygon, tolerance_ratio=1e-12)
     assert len(new_polygon.exterior.coords) == 0  # empty / collinear polygons should get deleted
+
+
+def test_snap_coords_outside():
+    """Test coordinate snapping for box geometries."""
+    num_coords = 101
+    coords_to_snap = np.linspace(-1, 1, num_coords)
+
+    coord_face_min = np.mean(coords_to_snap[0:2])
+    coord_face_max = np.mean(coords_to_snap[-2:])
+
+    snap_pt_min = td.Box._snap_coords_outside(
+        min_max_index=0, snap_coords_values=coords_to_snap, coord_normal_face=coord_face_min
+    )
+    snap_pt_max = td.Box._snap_coords_outside(
+        min_max_index=1, snap_coords_values=coords_to_snap, coord_normal_face=coord_face_max
+    )
+
+    assert snap_pt_min == coords_to_snap[0], "Unexpected snapping point minimum"
+    assert snap_pt_max == coords_to_snap[-1], "Unexpected snapping point maximum"
+
+    with AssertLogLevel("WARNING", contains_str="Unable to snap coordinates outside"):
+        snap_pt_min = td.Box._snap_coords_outside(
+            min_max_index=0,
+            snap_coords_values=coords_to_snap,
+            coord_normal_face=coords_to_snap[0] - 0.1,
+        )
+
+        assert snap_pt_min == coords_to_snap[0], "Unexpected snapping point minimum"
+
+    with AssertLogLevel("WARNING", contains_str="Unable to snap coordinates outside"):
+        snap_pt_min = td.Box._snap_coords_outside(
+            min_max_index=1,
+            snap_coords_values=coords_to_snap,
+            coord_normal_face=coords_to_snap[-1] + 0.1,
+        )
+
+        assert snap_pt_min == coords_to_snap[-1], "Unexpected snapping point maxium"
+
+
+def test_singularity_correction_pec():
+    """Tests singularity correction detection used for PEC gradients of `Box` geometries."""
+
+    check_3d_size = (1.0, 2.0, 3.0)
+
+    for axis in range(3):
+        is_2d, zero_dimension, do_singularity_correction = td.Box._check_singularity_correction_pec(
+            size=check_3d_size, axis_normal=axis
+        )
+        assert not is_2d, "Unexpectedly found 2D geometry"
+        assert not zero_dimension, "Unexpectedly found zero_dimension"
+        assert not do_singularity_correction, (
+            "Unexpectedly identifying need for singularity correction"
+        )
+
+    check_1d_error_size = (1.0, 0.0, 0.0)
+
+    for axis in range(3):
+        with AssertLogLevel(
+            "ERROR", contains_str="Derivative of PEC material with less than 2 dimensions"
+        ):
+            is_2d, zero_dimension, do_singularity_correction = (
+                td.Box._check_singularity_correction_pec(size=check_1d_error_size, axis_normal=axis)
+            )
+
+    check_2d_size = 1.0
+
+    for index_2d in range(3):
+        check_2d_size = tuple(0.0 if idx == index_2d else 1.0 for idx in range(3))
+
+        for axis in range(3):
+            print(f"check 2d size = {check_2d_size}")
+
+            is_2d, zero_dimension, do_singularity_correction = (
+                td.Box._check_singularity_correction_pec(size=check_2d_size, axis_normal=axis)
+            )
+
+            print(f"is 2d = {is_2d}")
+
+            assert is_2d, "Expected 2D geometry detection"
+            assert zero_dimension == "xyz"[index_2d], "Wrong zero dimension identified"
+
+            if axis == index_2d:
+                assert not do_singularity_correction, (
+                    "Unexpectedly detecting need for singularity correction"
+                )
+            else:
+                assert do_singularity_correction, (
+                    "Unexpectedly not detecting need for singularity correction"
+                )
+
+
+def test_trim_dims_and_bounds_edge():
+    """Tests the dimension and bound trimming for 2D PEC gradient integrations in `Box`."""
+
+    for zero_dimension_idx in range(3):
+        box = td.Box(
+            center=(0.0, 0.0, 0.0),
+            size=tuple(0.0 if zero_dimension_idx == idx else 1.0 * (idx + 1) for idx in range(3)),
+        )
+
+        for axis_normal in range(3):
+            if axis_normal == zero_dimension_idx:
+                continue
+
+            dim_normal, dims_perp = box.pop_axis("xyz", axis=axis_normal)
+            bounds_normal, bounds_perp = box.pop_axis(np.array(box.bounds).T, axis=axis_normal)
+            bounds_perp = np.array(bounds_perp).T
+
+            trimmed_dims, trimmed_bounds = td.Box._trim_dims_and_bounds_edge(
+                dims_perp=dims_perp,
+                bounds_perp=bounds_perp,
+                zero_dimension="xyz"[zero_dimension_idx],
+            )
+
+            expected_trimmed_idx = 0
+            for idx in range(3):
+                if (idx == axis_normal) or (idx == zero_dimension_idx):
+                    continue
+
+                expected_trimmed_idx = idx
+
+            expected_trimmed_dims = ("xyz"[expected_trimmed_idx],)
+            expected_trimmed_bounds = (
+                (-0.5 * (expected_trimmed_idx + 1),),
+                (0.5 * (expected_trimmed_idx + 1),),
+            )
+
+            assert np.all(np.array(expected_trimmed_dims) == np.array(trimmed_dims)), (
+                "Unexpected trimmed dims"
+            )
+            assert np.all(np.array(expected_trimmed_bounds) == np.array(trimmed_bounds)), (
+                "Unexpected trimmed bounds"
+            )