Fixing non-second timedelta64 bug

parcels/tools/converters.py

@@ -57,10 +57,13 @@
         self.time_origin = time_origin
         self.calendar: str | None = None
         if isinstance(time_origin, np.datetime64):
+            self.time_origin = time_origin
             self.calendar = "np_datetime64"
         elif isinstance(time_origin, np.timedelta64):
+            self.time_origin = time_origin.astype("timedelta64[ns]")
             self.calendar = "np_timedelta64"
         elif isinstance(time_origin, cftime.datetime):
+            self.time_origin = time_origin
             self.calendar = time_origin.calendar
 
     def reltime(self, time: TimeConverter | np.datetime64 | np.timedelta64 | cftime.datetime) -> float | npt.NDArray:
@@ -79,8 +82,10 @@
 
         """
         time = time.time_origin if isinstance(time, TimeConverter) else time
-        if self.calendar in ["np_datetime64", "np_timedelta64"]:
+        if self.calendar in ["np_datetime64"]:
             return (time - self.time_origin) / np.timedelta64(1, "s")  # type: ignore
+        elif self.calendar in ["np_timedelta64"]:
+            return (time - self.time_origin) / np.timedelta64(1, "ns")  # type: ignore
         elif self.calendar in _get_cftime_calendars():
             if isinstance(time, (list, np.ndarray)):
                 try:

tests/tools/test_converters.py

@@ -40,6 +40,18 @@ def test_TimeConverter_reltime_one_day():
         assert tc.reltime(time) == ONE_DAY
 
 
+def test_TimeConverter_timedelta64_float():
+    ONE_DAY = 24 * 60 * 60
+    tc = TimeConverter(np.timedelta64(0, "s"))
+    assert tc.reltime(1 * ONE_DAY) == 1 * ONE_DAY
+
+    tc = TimeConverter(np.timedelta64(0, "D"))
+    assert tc.reltime(1 * ONE_DAY) == 1 * ONE_DAY
+
+    tc = TimeConverter(np.timedelta64(0, "ns"))
+    assert tc.reltime(1 * ONE_DAY) == 1 * ONE_DAY
+
+
 @pytest.mark.parametrize(
     "x, y",
     [