STAR: iSWAP.request_is_parked, and two channels a pitch apart are not too close

The name answers a yes/no question, so it reads as one: `request_is_parked`, callers and tests
renamed with it.

Spots exactly one pitch apart were refused as too close for a tip command: the Y difference of two
float positions is off by float error (130.7 - 121.7 is 8.999999999999986), while the command
carries tenths. The gap is rounded to 0.1 mm before it is compared.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: BioCam

pylabrobot/hamilton/star/driver/features/iswap.py

@@ -3049,7 +3049,7 @@ async def request_pose(self) -> iSWAPPose:
 
   # -- parking ---------------------------------------------------------------
 
-  async def request_parked(self, tolerance_increments: int = 2) -> bool:
+  async def request_is_parked(self, tolerance_increments: int = 2) -> bool:
     """Whether the arm is parked, judged from where its drives are.
 
     Each drive is checked against the parking stop in its stored table, which setup reads:

pylabrobot/hamilton/star/driver/features/iswap_tests.py

@@ -89,7 +89,7 @@ async def test_the_arm_is_parked_when_every_drive_is_at_its_parking_position(sel
         }
       ),
     ):
-      self.assertTrue(await iswap.request_parked())
+      self.assertTrue(await iswap.request_is_parked())
 
   async def test_the_arm_is_not_parked_when_a_drive_is_moved(self):
     iswap, _ = await gripper()
@@ -100,7 +100,7 @@ async def test_the_arm_is_not_parked_when_a_drive_is_moved(self):
       c.elbow_predefined_y_positions_increments.parking - 10
     )
     with patch.object(iswap, "request_joint_state", new=AsyncMock(return_value=joints)):
-      self.assertFalse(await iswap.request_parked())
+      self.assertFalse(await iswap.request_is_parked())
 
   async def test_z_above_the_parking_position_is_still_parked(self):
     iswap, _ = await gripper()
@@ -112,7 +112,7 @@ async def test_z_above_the_parking_position_is_still_parked(self):
       + c.elbow_z_offset_above_finger
     )
     with patch.object(iswap, "request_joint_state", new=AsyncMock(return_value=joints)):
-      self.assertTrue(await iswap.request_parked())
+      self.assertTrue(await iswap.request_is_parked())
 
 
 class TestJawMoves(unittest.IsolatedAsyncioTestCase):
@@ -385,7 +385,7 @@ async def test_it_never_asks_the_master_for_its_parked_flag(self):
     """`C0 RG` is answered wrongly by the firmware, so nothing may read it."""
     iswap, sent = await gripper()
 
-    await iswap.request_parked()
+    await iswap.request_is_parked()
 
     self.assertEqual([command for command in sent if command.startswith("C0RG")], [])
 
@@ -394,13 +394,13 @@ async def test_a_parked_arm_is_parked_and_a_moved_one_is_not(self):
     c = iswap.configuration
 
     await iswap.park()
-    self.assertTrue(await iswap.request_parked())
+    self.assertTrue(await iswap.request_is_parked())
 
     assert c.elbow_predefined_y_positions_increments is not None
     await iswap.elbow_move_to_y_position(
       c.y_increments_to_mm(c.elbow_predefined_y_positions_increments.parking) - 50.0
     )
-    self.assertFalse(await iswap.request_parked())
+    self.assertFalse(await iswap.request_is_parked())
 
   async def test_the_jaws_are_part_of_it(self):
     """Parking closes them, and the gripper's table names that stop its home."""
@@ -412,7 +412,7 @@ async def test_the_jaws_are_part_of_it(self):
     home = c.gripper_increments_to_mm(c.gripper_drive_predefined_increments.home)
     await iswap.gripper_move_to_jaw_position(home + 5.0)
 
-    self.assertFalse(await iswap.request_parked())
+    self.assertFalse(await iswap.request_is_parked())
 
   async def test_a_drive_within_the_tolerance_still_counts_as_parked(self):
     iswap, _ = await gripper()
@@ -424,9 +424,9 @@ async def test_a_drive_within_the_tolerance_still_counts_as_parked(self):
     assert c.elbow_predefined_y_positions_increments is not None
     stop = c.elbow_predefined_y_positions_increments.parking
     iswap.update_location_by_reference_point(y=c.y_increments_to_mm(stop + 2))
-    self.assertTrue(await iswap.request_parked())
+    self.assertTrue(await iswap.request_is_parked())
     iswap.update_location_by_reference_point(y=c.y_increments_to_mm(stop + 20))
-    self.assertFalse(await iswap.request_parked())
+    self.assertFalse(await iswap.request_is_parked())
 
   async def test_a_parked_arm_above_its_z_stop_is_parked_and_below_it_is_not(self):
     """Parked from 284 mm, the device stands at `rz` 26660 against a stop of 25400."""
@@ -438,9 +438,9 @@ async def test_a_parked_arm_above_its_z_stop_is_parked_and_below_it_is_not(self)
     offset = c.elbow_z_offset_above_finger
 
     iswap.update_location_by_reference_point(z=c.z_increments_to_mm(stop + 1260) + offset)
-    self.assertTrue(await iswap.request_parked())
+    self.assertTrue(await iswap.request_is_parked())
     iswap.update_location_by_reference_point(z=c.z_increments_to_mm(stop - 20) + offset)
-    self.assertFalse(await iswap.request_parked())
+    self.assertFalse(await iswap.request_is_parked())
 
 
 class TestElbowXMoves(unittest.IsolatedAsyncioTestCase):

pylabrobot/hamilton/star/driver/features/pipettes.py

@@ -465,7 +465,7 @@ async def _require_iswap_parked(self) -> None:
       RuntimeError: If it is not parked.
     """
     iswap = self.arm.iswap
-    if iswap is not None and not await iswap.request_parked():
+    if iswap is not None and not await iswap.request_is_parked():
       raise RuntimeError(
         "the iSWAP is not parked, and the channels move where it stands. "
         "Call `await star.iswap.park()` first."
@@ -3661,15 +3661,15 @@ def _tip_command_positions(
       ys.append(round(centre.y * 10))
       placed[channel] = (centre.x, centre.y)
 
-    # As legacy checks them: each pair taking part by itself, not the channels between them. Where
-    # those leave the pair too little room, the firmware arranges the channels, as it does for
-    # legacy's commands.
+    # Each pair taking part by itself, as legacy checks them; the firmware arranges the channels
+    # between. Distances in tenths, as the command carries them: 9.0 mm is 9.0 mm, float or not.
     for i, (xi, yi) in placed.items():
       for j, (xj, yj) in placed.items():
         # Channels in different columns are separate moves on the device.
-        if i < j and round(xi, 1) == round(xj, 1) and abs(yi - yj) < self._min_pair_spacing(i, j):
+        apart = round(abs(yi - yj), 1)
+        if i < j and round(xi, 1) == round(xj, 1) and apart < self._min_pair_spacing(i, j):
           raise ValueError(
-            f"channels {i} and {j} would be {abs(yi - yj):.1f} mm apart in Y, closer than "
+            f"channels {i} and {j} would be {apart} mm apart in Y, closer than "
             f"{self._min_pair_spacing(i, j)} mm"
           )
 

pylabrobot/hamilton/star/driver/features/pipettes_tests.py

@@ -457,7 +457,7 @@ async def test_not_parked_refuses(self):
     async def not_parked(*args: Any, **kwargs: Any) -> bool:
       return False
 
-    iswap.request_parked = not_parked  # type: ignore[method-assign]
+    iswap.request_is_parked = not_parked  # type: ignore[method-assign]
     with self.assertRaises(RuntimeError):
       await self.pipettes._require_iswap_parked()
 
@@ -2144,6 +2144,14 @@ async def test_a_pickup_brings_the_other_channels_along_in_y(self):
         f"channels {channel} and {channel + 1} stand too close: {order}",
       )
 
+  async def test_spots_a_pitch_apart_in_floating_point_are_accepted(self):
+    # 130.7 - 121.7 is 8.999999999999986 in floating point; the command carries 9.0 mm.
+    pipettes, _, _ = await channels_over_a_rack()
+    _, ys, _ = pipettes._tip_command_positions(
+      {0: Coordinate(300.0, 130.7, 150.0), 1: Coordinate(300.0, 121.7, 150.0)}
+    )
+    self.assertEqual(ys[:2], [1307, 1217])
+
 
 class TestTipsOfDifferentKinds(unittest.IsolatedAsyncioTestCase):
   """A command names one tip type, so spots holding different tips go out in separate commands."""