observe cell traitlet

Author: eimrek

example/example.ipynb

@@ -41,6 +41,20 @@
     "display(bz)"
    ]
   },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# update cell:\n",
+    "bz.cell = [\n",
+    "    [5.0, 0.0, 0.0],\n",
+    "    [0.0, 1.0, 0.0],\n",
+    "    [0.0, 0.0, 1.0],\n",
+    "]"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,

src/widget_bzvisualizer/__init__.py

@@ -2,7 +2,7 @@
 import pathlib
 
 import anywidget
-import traitlets
+import traitlets as tl
 
 from . import utils
 
@@ -16,17 +16,26 @@ class BZVisualizer(anywidget.AnyWidget):
     _esm = pathlib.Path(__file__).parent / "static" / "widget.js"
     _css = pathlib.Path(__file__).parent / "static" / "widget.css"
 
-    seekpath_data = traitlets.Dict({}).tag(sync=True)
+    # primary input parameters, not directly used in the JS app
+    cell = tl.List().tag(sync=True)
+    rel_coords = tl.List().tag(sync=True)
+    atom_numbers = tl.List().tag(sync=True)
 
-    # parameters passed to the js BZVisualizer
-    show_axes = traitlets.Bool(True).tag(sync=True)
-    show_bvectors = traitlets.Bool(True).tag(sync=True)
-    show_pathpoints = traitlets.Bool(False).tag(sync=True)
-    disable_interact_overlay = traitlets.Bool(False).tag(sync=True)
+    # auxiliary traitlet to easily manage the previous ones
+    system = tl.Dict({}).tag(sync=True)
 
-    # Parameters to control the size of the div-container
-    width = traitlets.Unicode("100%").tag(sync=True)
-    height = traitlets.Unicode("400px").tag(sync=True)
+    # Data used in the JS app
+    seekpath_data = tl.Dict({}).tag(sync=True)
+
+    # optional parameters passed to the JS BZVisualizer
+    show_axes = tl.Bool(True).tag(sync=True)
+    show_bvectors = tl.Bool(True).tag(sync=True)
+    show_pathpoints = tl.Bool(False).tag(sync=True)
+    disable_interact_overlay = tl.Bool(False).tag(sync=True)
+
+    # parameters to control the size of the div-container
+    width = tl.Unicode("100%").tag(sync=True)
+    height = tl.Unicode("400px").tag(sync=True)
 
     def __init__(
         self,
@@ -40,6 +49,14 @@ def __init__(
         The traitlets defined above can be set as a kwargs.
         """
         super().__init__(**kwargs)
-        self.seekpath_data = utils.get_seekpath_data_for_visualizer(
-            cell, rel_coords, atom_numbers
-        )
+        self.system = {
+            "cell": cell,
+            "rel_coords": rel_coords,
+            "atom_numbers": atom_numbers,
+        }
+        self.seekpath_data = utils.get_seekpath_data_for_visualizer(self.system)
+
+    @tl.observe("cell")
+    def _cell_changed(self, change):
+        self.system[change["name"]] = change["new"]
+        self.seekpath_data = utils.get_seekpath_data_for_visualizer(self.system)

src/widget_bzvisualizer/utils.py

@@ -3,8 +3,12 @@
 from seekpath.brillouinzone.brillouinzone import get_BZ
 
 
-def get_seekpath_data_for_visualizer(cell, relcoords, atomic_numbers):
-    system = (np.array(cell), np.array(relcoords), np.array(atomic_numbers))
+def get_seekpath_data_for_visualizer(system):
+    system = (
+        np.array(system["cell"]),
+        np.array(system["rel_coords"]),
+        np.array(system["atom_numbers"]),
+    )
     res = seekpath.get_explicit_k_path(system, with_time_reversal=False)
 
     b1, b2, b3 = res["reciprocal_primitive_lattice"]