Update create_particle_data arg

Make it explicitly an initial dict rather than as kwargs

Author: VeckoTheGecko

parcels/particle.py

@@ -189,8 +189,16 @@ def get_default_particle(spatial_dtype: np.float32 | np.float64) -> ParticleClas
 
 
 def create_particle_data(
-    *, pclass: ParticleClass, nparticles: int, ngrids: int, time_interval: TimeInterval, **initial: dict[str, np.array]
+    *,
+    pclass: ParticleClass,
+    nparticles: int,
+    ngrids: int,
+    time_interval: TimeInterval,
+    initial: dict[str, np.array] | None,
 ):
+    if initial is None:
+        initial = {}
+
     variables = {var.name: var for var in pclass.variables}
 
     assert "ei" not in initial, "'ei' is for internal use, and is unique since is only non 1D array"

parcels/particleset.py

@@ -122,15 +122,17 @@ def __init__(
             nparticles=lon.size,
             ngrids=len(fieldset.gridset),
             time_interval=fieldset.time_interval,
-            lon=lon,
-            lat=lat,
-            depth=depth,
-            time=time,
-            lon_nextloop=lon,
-            lat_nextloop=lat,
-            depth_nextloop=depth,
-            time_nextloop=time,
-            id=trajectory_ids,
+            initial=dict(
+                lon=lon,
+                lat=lat,
+                depth=depth,
+                time=time,
+                lon_nextloop=lon,
+                lat_nextloop=lat,
+                depth_nextloop=depth,
+                time_nextloop=time,
+                id=trajectory_ids,
+            ),
         )
         self._ptype = pclass