Removing lastID variable, and adding more tests

Author: erikvansebille

parcels/particle.py

@@ -193,10 +193,6 @@ def set_lonlatdepth_dtype(cls, dtype):
         cls.lat_nextloop.dtype = dtype
         cls.depth_nextloop.dtype = dtype
 
-    @classmethod
-    def setLastID(cls, offset):  # TODO v4: check if we can implement this in another way
-        Particle.lastID = offset
-
 
 InteractionParticle = Particle.add_variables(
     [Variable("vert_dist", dtype=np.float32), Variable("horiz_dist", dtype=np.float32)]

parcels/particleset.py

@@ -248,9 +248,11 @@ def add(self, particles):
 
         """
         if isinstance(particles, type(self)):
-            particles._data["trajectory"] = (
-                particles._data["trajectory"].values + self._data["trajectory"].values.max() + 1
-            )
+            if len(self._data["trajectory"]) > 0:
+                offset = self._data["trajectory"].values.max() + 1
+            else:
+                offset = 0
+            particles._data["trajectory"] = particles._data["trajectory"].values + offset
         self._data = xr.concat([self._data, particles._data], dim="trajectory")
         # Adding particles invalidates the neighbor search structure.
         self._dirty_neighbor = True
@@ -646,10 +648,7 @@ def from_particlefile(
             if v not in ["lon", "lat", "depth", "time", "id"]:
                 kwargs[v] = vars[v]
 
-        if restart:
-            pclass.setLastID(0)  # reset to zero offset
-        else:
-            vars["id"] = None
+        vars["id"] = None
 
         return cls(
             fieldset=fieldset,

tests/v4/test_particleset.py

@@ -202,6 +202,22 @@ def test_pset_add_implicit(fieldset):
     assert np.allclose(np.diff(pset._data.trajectory), np.ones(6), atol=1e-12)
 
 
+def test_pset_add_execute(fieldset, npart=10):
+    pset = ParticleSet(fieldset, lon=[], lat=[])
+    for _ in range(npart):
+        pset += ParticleSet(pclass=Particle, lon=0.1, lat=0.1, fieldset=fieldset)
+    assert pset.size == npart
+
+
+def test_pset_merge_inplace(fieldset, npart=100):
+    pset1 = ParticleSet(fieldset, lon=np.linspace(0, 1, npart), lat=np.linspace(1, 0, npart))
+    pset2 = ParticleSet(fieldset, lon=np.linspace(0, 1, npart), lat=np.linspace(0, 1, npart))
+    assert pset1.size == npart
+    assert pset2.size == npart
+    pset1.add(pset2)
+    assert pset1.size == 2 * npart
+
+
 def test_pset_iterator(fieldset):
     npart = 10
     pset = ParticleSet(fieldset, lon=np.zeros(npart), lat=np.ones(npart))