Merge pull request #206 from OceanParcels/changing_kernels_in_script_bug

Changing kernels in script bug fixed

Author: erikvansebille

parcels/particleset.py

@@ -221,7 +221,7 @@ def execute(self, pyfunc=AdvectionRK4, starttime=None, endtime=None, dt=1.,
                          kernel errors.
         :param show_movie: True shows particles; name of field plots that field as background
         """
-        if self.kernel is None:
+        if self.kernel is None or self.kernel.pyfunc is not pyfunc:
             # Generate and store Kernel
             if isinstance(pyfunc, Kernel):
                 self.kernel = pyfunc

tests/test_kernel_execution.py

@@ -189,3 +189,23 @@ def MoveWest(particle, fieldset, time, dt):
     pset.execute(pset.Kernel(MoveEast) + pset.Kernel(MoveWest),
                  starttime=0., endtime=1., dt=1.)
     assert np.allclose([p.lon for p in pset], 0.3, rtol=1e-5)
+
+
+@pytest.mark.parametrize('mode', ['scipy', 'jit'])
+def test_update_kernel_in_script(fieldset, mode):
+    # Testing what happens when kernels are updated during runtime of a script
+    # Should throw a warning, but go ahead regardless
+    def MoveEast(particle, fieldset, time, dt):
+        add_lon = 0.1
+        particle.lon += add_lon
+
+    def MoveWest(particle, fieldset, time, dt):
+        add_lon = -0.3
+        particle.lon += add_lon
+
+    pset = ParticleSet(fieldset, pclass=ptype[mode], lon=[0.5], lat=[0.5])
+    pset.execute(pset.Kernel(MoveEast),
+                 starttime=0., endtime=1., dt=1.)
+    pset.execute(pset.Kernel(MoveWest),
+                 starttime=1., endtime=2., dt=1.)
+    assert np.allclose([p.lon for p in pset], 0.3, rtol=1e-5)  # should be 0.5 + 0.1 - 0.3 = 0.3