feat: support sub-hourly steps (#188)

Author: b8raoult

src/anemoi/datasets/create/input/result.py

@@ -15,6 +15,7 @@
 from functools import cached_property
 
 import numpy as np
+from anemoi.utils.dates import as_timedelta
 from anemoi.utils.humanize import seconds_to_human
 from anemoi.utils.humanize import shorten_list
 from earthkit.data.core.order import build_remapping
@@ -97,10 +98,12 @@ def _merge(md1, md2):
             # assert md['param'] != 'unknown', (md, f.metadata('param'))
 
         startStep = f.metadata("startStep", default=None)
-        assert startStep is None or isinstance(startStep, int), (startStep, type(f))
+        if startStep is not None:
+            startStep = as_timedelta(startStep)
 
         endStep = f.metadata("endStep", default=None)
-        assert endStep is None or isinstance(endStep, int), endStep
+        if endStep is not None:
+            endStep = as_timedelta(endStep)
 
         stepTypeForConversion = f.metadata("stepTypeForConversion", default=None)
         typeOfStatisticalProcessing = f.metadata("typeOfStatisticalProcessing", default=None)

src/anemoi/datasets/data/dataset.py

@@ -541,6 +541,13 @@ def plot(self, date, variable, member=0, **kwargs):
         """
 
         from anemoi.utils.devtools import plot_values
+
+        values = self[self.to_index(date, variable, member)]
+
+        return plot_values(values, self.latitudes, self.longitudes, **kwargs)
+
+    def to_index(self, date, variable, member=0):
+
         from earthkit.data.utils.dates import to_datetime
 
         if not isinstance(date, int):
@@ -562,6 +569,4 @@ def plot(self, date, variable, member=0, **kwargs):
 
             variable_index = self.name_to_index[variable]
 
-        values = self[date_index, variable_index, member]
-
-        return plot_values(values, self.latitudes, self.longitudes, **kwargs)
+        return (date_index, variable_index, member)