Added boundaries iterator to Boundaries class (#536)

pde/grids/_mesh.py

@@ -706,7 +706,7 @@ def gather(self, data: TData) -> list[TData] | None:
         """
         from mpi4py.MPI import COMM_WORLD  # @UnresolvedImport
 
-        return COMM_WORLD.gather(data, root=0)  # type: ignore
+        return COMM_WORLD.gather(data, root=0)
 
     def allgather(self, data: TData) -> list[TData]:
         """gather a value from reach node and sends them to all nodes
@@ -720,7 +720,7 @@ def allgather(self, data: TData) -> list[TData]:
         """
         from mpi4py.MPI import COMM_WORLD  # @UnresolvedImport
 
-        return COMM_WORLD.allgather(data)  # type: ignore
+        return COMM_WORLD.allgather(data)
 
     @plot_on_axes()
     def plot(self, ax, **kwargs) -> None:

pde/grids/boundaries/axes.py

@@ -8,7 +8,7 @@
 
 from __future__ import annotations
 
-from collections.abc import Sequence
+from collections.abc import Iterator, Sequence
 from typing import Union
 
 import numpy as np
@@ -17,7 +17,7 @@
 from ...tools.typing import GhostCellSetter
 from ..base import GridBase, PeriodicityError
 from .axis import BoundaryPair, BoundaryPairData, get_boundary_axis
-from .local import BCDataError
+from .local import BCBase, BCDataError
 
 BoundariesData = Union[BoundaryPairData, Sequence[BoundaryPairData]]
 
@@ -170,6 +170,13 @@ def __eq__(self, other):
             return NotImplemented
         return super().__eq__(other) and self.grid == other.grid
 
+    @property
+    def boundaries(self) -> Iterator[BCBase]:
+        """iterator over all non-periodic boundaries"""
+        for boundary_axis in self:  # iterate all axes
+            if not boundary_axis.periodic:  # skip periodic axes
+                yield from boundary_axis
+
     def check_value_rank(self, rank: int) -> None:
         """check whether the values at the boundaries have the correct rank
 

tests/grids/boundaries/test_axes_boundaries.py

@@ -11,6 +11,7 @@
 from pde.grids.base import PeriodicityError
 from pde.grids.boundaries.axes import BCDataError, Boundaries
 from pde.grids.boundaries.axis import BoundaryPair, BoundaryPeriodic, get_boundary_axis
+from pde.grids.boundaries.local import NeumannBC
 
 
 def test_boundaries():
@@ -181,4 +182,17 @@ def test_setting_specific_bcs():
     with pytest.raises(KeyError):
         bcs["nonsense"] = None
 
-    # test different ranks
+
+def test_boundaries_property():
+    """test boundaries property"""
+    g = UnitGrid([2, 2])
+    bc = Boundaries.from_data(g, ["neumann", "dirichlet"])
+    assert len(list(bc.boundaries)) == 4
+
+    bc = Boundaries.from_data(g, "neumann")
+    for b in bc.boundaries:
+        assert isinstance(b, NeumannBC)
+
+    g = UnitGrid([2, 2], periodic=[True, False])
+    bc = Boundaries.from_data(g, "auto_periodic_neumann")
+    assert len(list(bc.boundaries)) == 2