fix: first timestep is not startdate but startdate + dt

apps/hiopy/configure/configure.py

@@ -9,10 +9,10 @@ def add_time(dataset, startdate, enddate, dt, name="time"):
         startdate = np.datetime64(startdate)
     if type(enddate) is str:
         enddate = np.datetime64(enddate)
+    if type(dt) is int:
+        dt = np.timedelta64(dt, "s")
 
-    time_data = (
-        np.arange(startdate, enddate, np.timedelta64(dt, "s")) - startdate
-    ) // np.timedelta64(1, "s")
+    time_data = (np.arange(startdate + dt, enddate + dt, dt) - startdate) // np.timedelta64(1, "s")
 
     for g in _collect_groups(dataset):
         time = g.create_dataset(name, data=time_data, fill_value=None, shape=time_data.shape)

apps/hiopy/worker.py

@@ -131,15 +131,14 @@ def main():
                 "seconds since " in time_coordinate.attrs["units"]
             ), "Currently the time must be given in seconds"
 
+            dt = time_coordinate[1] - time_coordinate[0]
             # compute time start index
             t0 = (
                 np.datetime64(start_datetime())
-                - np.datetime64(var_group["time"].attrs["units"][len("seconds since ") :])
-            ) / np.timedelta64(1, "s")
-            t0_idx = np.searchsorted(var_group["time"], t0)
-            assert var_group["time"][t0_idx] == t0, "start_datetime not found in time axis"
-
-            dt = time_coordinate[t0_idx + 1] - time_coordinate[t0_idx]
+                - np.datetime64(var_group[time_dim_name].attrs["units"][len("seconds since ") :])
+            ) / np.timedelta64(1, "s") + dt
+            t0_idx = np.searchsorted(var_group[time_dim_name], t0)
+            assert var_group[time_dim_name][t0_idx] == t0, "start_datetime not found in time axis"
 
             # see YAC_REDUCTION_TIME_NONE etc. (TODO: pass constants through coyote)
             time_methods2yac = {"point": 0, "sum": 1, "mean": 2, "min": 3, "max": 4}