Make bounding_box a cached property of TreeOfBoxes

boxtree/tree.py

@@ -81,6 +81,7 @@
 """
 
 from typing import Tuple
+from functools import cached_property
 
 import pyopencl as cl
 import numpy as np
@@ -214,8 +215,6 @@ class TreeOfBoxes:
     box_child_ids: np.ndarray
     box_levels: np.ndarray
 
-    bounding_box: Tuple[np.ndarray, np.ndarray]
-
     box_flags: np.ndarray
     level_start_box_nrs: np.ndarray
 
@@ -260,6 +259,12 @@ def leaf_boxes(self):
         boxes = np.arange(self.nboxes)
         return boxes[self.leaf_flags]
 
+    @cached_property
+    def bounding_box(self) -> Tuple[np.ndarray, np.ndarray]:
+        lows = self.box_centers[:, 0] - 0.5 * self.root_extent
+        highs = lows + self.root_extent
+        return lows, highs
+
     # {{{ dummy interface for TreePlotter
 
     def get_box_size(self, ibox):

boxtree/tree_of_boxes.py

@@ -59,14 +59,6 @@
 
 # {{{ utils for tree of boxes
 
-def _tob_bounding_box(
-        box_centers: np.ndarray, root_extent: np.ndarray,
-        ) -> Tuple[np.ndarray, np.ndarray]:
-    lows = box_centers[:, 0] - 0.5 * root_extent
-    highs = lows + root_extent
-    return lows, highs
-
-
 def _resized_array(arr: np.ndarray, new_size: int) -> np.ndarray:
     """Return a resized copy of the array. The new_size is a scalar which is
     applied to the last dimension.
@@ -173,7 +165,6 @@ def _apply_refine_flags_without_sorting(refine_flags, tob):
         box_parent_ids=box_parents,
         box_child_ids=box_children,
         box_levels=box_levels,
-        bounding_box=_tob_bounding_box(box_centers, tob.root_extent),
         )
 
 
@@ -236,7 +227,6 @@ def _sort_boxes_by_level(tob, queue=None):
         box_parent_ids=box_parent_ids,
         box_child_ids=box_child_ids,
         box_levels=box_levels,
-        bounding_box=_tob_bounding_box(box_centers, tob.root_extent),
         )
 
 
@@ -346,7 +336,6 @@ def make_tree_of_boxes_root(
             box_parent_ids=box_parent_ids,
             box_child_ids=np.array([0] * 2**dim, box_id_dtype).reshape(2**dim, 1),
             box_levels=np.array([0], box_level_dtype),
-            bounding_box=_tob_bounding_box(box_centers, root_extent),
 
             box_flags=np.empty(1, dtype=box_flags_enum.dtype),
             level_start_box_nrs=np.array([0], dtype=box_level_dtype),

test/test_tree_of_boxes.py

@@ -219,7 +219,6 @@ def test_traversal_from_tob(actx_factory):
         box_parent_ids=actx.from_numpy(tob.box_parent_ids),
         box_child_ids=actx.from_numpy(tob.box_child_ids),
         box_levels=actx.from_numpy(tob.box_levels),
-        bounding_box=tob.bounding_box,
         box_flags=actx.from_numpy(tob.box_flags),
         )