Fix ravel_index call for uxgrid grids

Author: fluidnumericsJoe

parcels/field.py

@@ -345,13 +345,21 @@ def __getitem__(self, key):
 def _update_particles_ei(particles, position, field):
     """Update the element index (ei) of the particles"""
     if particles is not None:
-        particles.ei[:, field.igrid] = field.grid.ravel_index(
-            {
-                "X": position["X"][0],
-                "Y": position["Y"][0],
-                "Z": position["Z"][0],
-            }
-        )
+        if isinstance(field.grid, XGrid):
+            particles.ei[:, field.igrid] = field.grid.ravel_index(
+                {
+                    "X": position["X"][0],
+                    "Y": position["Y"][0],
+                    "Z": position["Z"][0],
+                }
+            )
+        elif isinstance(field.grid, UxGrid):
+            particles.ei[:, field.igrid] = field.grid.ravel_index(
+                {
+                    "Z": position["Z"][0],
+                    "FACE": position["FACE"][0],
+                }
+            )
 
 
 def _update_particle_states_position(particle, position):

tests/v4/test_particleset_execute.py

@@ -400,8 +400,8 @@ def test_uxstommelgyre_pset_execute():
         dt=np.timedelta64(60, "s"),
         pyfunc=AdvectionEE,
     )
-    assert utils.round_and_hash_float_array([p.lon for p in pset]) == 1165396086
-    assert utils.round_and_hash_float_array([p.lat for p in pset]) == 1142124776
+    assert utils.round_and_hash_float_array([p.lon for p in pset]) == 1165397121
+    assert utils.round_and_hash_float_array([p.lat for p in pset]) == 1142123780
 
 
 @pytest.mark.xfail(reason="Output file not implemented yet")