Rename _apply_counterpart_filter -> _drop_filtered_counterpart_contacts

"apply ... filter" didn't convey what the function does. It clears mask
entries for contacts whose counterpart link is filtered out, matching the
wording already used for this behavior elsewhere (e.g. the test docstring
"drops contacts whose counterpart is filtered"). The self-describing name
replaces the docstring, which is dropped.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Milotrince

genesis/engine/sensors/contact_force.py

@@ -39,12 +39,9 @@ def _func_link_is_filtered(filter_links_idx: qd.types.ndarray(), i_s: int, link:
     return is_filtered
 
 
-def _apply_counterpart_filter(is_a: torch.Tensor, is_b: torch.Tensor, link_a, link_b, shared_metadata) -> None:
-    """Zero out, in place, the contacts a filtered sensor should ignore. ``is_a``/``is_b`` are the per-side
-    "this contact touches the sensor link" masks, shape ``(B, n_sensors, n_contacts)``; when the sensor is on side
-    a its counterpart is ``link_b`` (and vice versa), so a contact is dropped when that counterpart is blacklisted.
-    Only the filtered-sensor rows are touched, so unfiltered sensors keep the cheap masks unchanged.
-    """
+def _drop_filtered_counterpart_contacts(
+    is_a: torch.Tensor, is_b: torch.Tensor, link_a, link_b, shared_metadata
+) -> None:
     filt = shared_metadata.filtered_sensor_idx
     if filt.numel() == 0:
         return
@@ -182,7 +179,7 @@ def _update_raw_data(cls, shared_context: None, shared_metadata: ContactSensorMe
 
         is_contact_a = link_a[..., None, :] == shared_metadata.expanded_links_idx[..., None]
         is_contact_b = link_b[..., None, :] == shared_metadata.expanded_links_idx[..., None]
-        _apply_counterpart_filter(is_contact_a, is_contact_b, link_a, link_b, shared_metadata)
+        _drop_filtered_counterpart_contacts(is_contact_a, is_contact_b, link_a, link_b, shared_metadata)
         # Float-valued contact count per sensor (intermediate cache is float; bool projection in `_post_process`).
         result = (is_contact_a | is_contact_b).sum(dim=-1).to(dtype=gs.tc_float)
         raw_data_T[:] = result.T
@@ -312,7 +309,7 @@ def _update_raw_data(
             # Forces are aggregated BEFORE moving them in local frame for efficiency.
             force_mask_a = link_a[:, None] == shared_metadata.links_idx[None, :, None]
             force_mask_b = link_b[:, None] == shared_metadata.links_idx[None, :, None]
-            _apply_counterpart_filter(force_mask_a, force_mask_b, link_a, link_b, shared_metadata)
+            _drop_filtered_counterpart_contacts(force_mask_a, force_mask_b, link_a, link_b, shared_metadata)
             force_mask = force_mask_b.to(dtype=gs.tc_float) - force_mask_a.to(dtype=gs.tc_float)
             sensors_force = (force_mask[..., None] * force[:, None]).sum(dim=2)
             sensors_quat = links_quat[:, shared_metadata.links_idx]