Merge pull request #1810 from OceanParcels/warn_particle_times_outsid…

…e_fieldset_time_bounds

Implement warning for particles initialised outside time domain

parcels/particleset.py

@@ -14,7 +14,7 @@
 from parcels._compat import MPI
 from parcels.application_kernels.advection import AdvectionRK4
 from parcels.compilation.codecompiler import GNUCompiler
-from parcels.field import NestedField
+from parcels.field import Field, NestedField
 from parcels.grid import CurvilinearGrid, GridType
 from parcels.interaction.interactionkernel import InteractionKernel
 from parcels.interaction.neighborsearch import (
@@ -32,7 +32,7 @@
 from parcels.tools.global_statics import get_package_dir
 from parcels.tools.loggers import logger
 from parcels.tools.statuscodes import StatusCode
-from parcels.tools.warnings import FileWarning
+from parcels.tools.warnings import ParticleSetWarning
 
 __all__ = ["ParticleSet"]
 
@@ -174,6 +174,8 @@ def ArrayClass_init(self, *args, **kwargs):
             raise NotImplementedError("If fieldset.time_origin is not a date, time of a particle must be a double")
         time = np.array([self.time_origin.reltime(t) if _convert_to_reltime(t) else t for t in time])
         assert lon.size == time.size, "time and positions (lon, lat, depth) do not have the same lengths."
+        if isinstance(fieldset.U, Field) and (not fieldset.U.allow_time_extrapolation):
+            _warn_particle_times_outside_fieldset_time_bounds(time, fieldset.U.grid.time_full)
 
         if lonlatdepth_dtype is None:
             lonlatdepth_dtype = self.lonlatdepth_dtype_from_field_interp_method(fieldset.U)
@@ -792,7 +794,7 @@ def from_particlefile(
                 f"Note that the `repeatdt` argument is not retained from {filename}, and that "
                 "setting a new repeatdt will start particles from the _new_ particle "
                 "locations.",
-                FileWarning,
+                ParticleSetWarning,
                 stacklevel=2,
             )
 
@@ -1247,6 +1249,22 @@ def _warn_outputdt_release_desync(outputdt: float, starttime: float, release_tim
             "Some of the particles have a start time difference that is not a multiple of outputdt. "
             "This could cause the first output of some of the particles that start later "
             "in the simulation to be at a different time than expected.",
-            FileWarning,
+            ParticleSetWarning,
             stacklevel=2,
         )
+
+
+def _warn_particle_times_outside_fieldset_time_bounds(release_times: np.ndarray, time_full: np.ndarray):
+    if np.any(release_times):
+        if np.any(release_times < time_full[0]):
+            warnings.warn(
+                "Some particles are set to be released before the fieldset's first time and allow_time_extrapolation is set to False.",
+                ParticleSetWarning,
+                stacklevel=2,
+            )
+        if np.any(release_times > time_full[-1]):
+            warnings.warn(
+                "Some particles are set to be released after the fieldset's last time and allow_time_extrapolation is set to False.",
+                ParticleSetWarning,
+                stacklevel=2,
+            )

parcels/tools/warnings.py

@@ -1,6 +1,6 @@
 import warnings
 
-__all__ = ["FieldSetWarning", "FileWarning", "KernelWarning"]
+__all__ = ["FieldSetWarning", "FileWarning", "KernelWarning", "ParticleSetWarning"]
 
 
 class FieldSetWarning(UserWarning):
@@ -13,6 +13,12 @@ class FieldSetWarning(UserWarning):
     pass
 
 
+class ParticleSetWarning(UserWarning):
+    """Warning that is raised when there are issues in the construction of the ParticleSet."""
+
+    pass
+
+
 class FileWarning(UserWarning):
     """Warning that is raised when there are issues with input or output files.
 

tests/test_particlesets.py

@@ -7,6 +7,7 @@
     FieldSet,
     JITParticle,
     ParticleSet,
+    ParticleSetWarning,
     ScipyParticle,
     StatusCode,
     Variable,
@@ -175,6 +176,14 @@ def test_pset_create_with_time(fieldset, mode):
     assert np.allclose([p.time for p in pset], time, rtol=1e-12)
 
 
+@pytest.mark.parametrize("mode", ["scipy", "jit"])
+def test_pset_create_outside_time(mode):
+    fieldset = create_fieldset_zeros_simple(withtime=True)
+    time = [-1, 0, 1, 20 * 86400]
+    with pytest.warns(ParticleSetWarning, match="Some particles are set to be released*"):
+        ParticleSet(fieldset, pclass=ptype[mode], lon=[0] * len(time), lat=[0] * len(time), time=time)
+
+
 @pytest.mark.parametrize("mode", ["scipy", "jit"])
 def test_pset_not_multipldt_time(fieldset, mode):
     times = [0, 1.1]

tests/tools/test_warnings.py

@@ -9,9 +9,9 @@
     AdvectionRK45,
     FieldSet,
     FieldSetWarning,
-    FileWarning,
     KernelWarning,
     ParticleSet,
+    ParticleSetWarning,
     ScipyParticle,
 )
 from tests.utils import TEST_DATA
@@ -62,7 +62,7 @@ def test_file_warnings(tmp_zarrfile):
     )
     pset = ParticleSet(fieldset=fieldset, pclass=ScipyParticle, lon=[0, 0], lat=[0, 0], time=[0, 1])
     pfile = pset.ParticleFile(name=tmp_zarrfile, outputdt=2)
-    with pytest.warns(FileWarning, match="Some of the particles have a start time difference.*"):
+    with pytest.warns(ParticleSetWarning, match="Some of the particles have a start time difference.*"):
         pset.execute(AdvectionRK4, runtime=3, dt=1, output_file=pfile)
 
 

tests/utils.py

@@ -72,15 +72,24 @@ def create_flat_positions(n_particle):
     return np.random.rand(n_particle * 3).reshape(3, n_particle)
 
 
-def create_fieldset_zeros_simple(xdim=40, ydim=100):
-    U = np.zeros((ydim, xdim), dtype=np.float32)
-    V = np.zeros((ydim, xdim), dtype=np.float32)
+def create_fieldset_zeros_simple(xdim=40, ydim=100, withtime=False):
     lon = np.linspace(0, 1, xdim, dtype=np.float32)
     lat = np.linspace(-60, 60, ydim, dtype=np.float32)
     depth = np.zeros(1, dtype=np.float32)
-    data = {"U": np.array(U, dtype=np.float32), "V": np.array(V, dtype=np.float32)}
     dimensions = {"lat": lat, "lon": lon, "depth": depth}
-    return FieldSet.from_data(data, dimensions)
+    if withtime:
+        tdim = 10
+        time = np.linspace(0, 86400, tdim, dtype=np.float64)
+        dimensions["time"] = time
+        datadims = (tdim, ydim, xdim)
+        allow_time_extrapolation = False
+    else:
+        datadims = (ydim, xdim)
+        allow_time_extrapolation = True
+    U = np.zeros(datadims, dtype=np.float32)
+    V = np.zeros(datadims, dtype=np.float32)
+    data = {"U": np.array(U, dtype=np.float32), "V": np.array(V, dtype=np.float32)}
+    return FieldSet.from_data(data, dimensions, allow_time_extrapolation=allow_time_extrapolation)
 
 
 def assert_empty_folder(path: Path):