TMSS-2344: only loop over unique gridded timestamps

SAS/TMSS/backend/services/scheduling/lib/constraints.py

@@ -904,15 +904,15 @@ def evaluate_sky_min_elevation_constraint(scheduling_unit: models.SchedulingUnit
 
         # evaluate at start/stop/center of observation
         # take along the relative start_time of this task compared to the scheduling unit's start_time
+        # currently we only check at bounds and center, we probably want to add some more samples in between later on
         task_proposed_start_time = proposed_start_time + task.relative_start_time
-        task_proposed_end_time = task_proposed_start_time + task.specified_duration
         task_proposed_center_time = task_proposed_start_time + task.specified_duration / 2
+        task_proposed_end_time = task_proposed_start_time + task.specified_duration
+        gridded_timestamps = set([gridder.grid_time(t) for t in (task_proposed_start_time, task_proposed_center_time, task_proposed_end_time)])
 
-        # currently we only check at bounds and center, we probably want to add some more samples in between later on
-        for timestamp in (task_proposed_start_time, task_proposed_center_time, task_proposed_end_time):
+        for gridded_timestamp in gridded_timestamps:
             for station in stations:
                 for pointing, min_elevation in pointings_and_min_elevations:
-                    gridded_timestamp = gridder.grid_time(timestamp)
                     station_target_rise_and_set_times = coordinates_timestamps_and_stations_to_target_rise_and_set(pointing=pointing,
                                                                                                                    timestamps=(gridded_timestamp,),
                                                                                                                    stations=(station,),
@@ -940,8 +940,8 @@ def evaluate_sky_min_elevation_constraint(scheduling_unit: models.SchedulingUnit
 
                     # check if constraint is met...
                     if rise_and_set_time['always_below_horizon'] or \
-                            (rise_and_set_time['rise'] is not None and timestamp < gridder.minus_margin(rise_and_set_time['rise'])) or \
-                            (rise_and_set_time['set'] is not None and timestamp > gridder.plus_margin(rise_and_set_time['set'])):
+                            (rise_and_set_time['rise'] is not None and gridded_timestamp < gridder.minus_margin(rise_and_set_time['rise'])) or \
+                            (rise_and_set_time['set'] is not None and gridded_timestamp > gridder.plus_margin(rise_and_set_time['set'])):
                         elevation = compute_elevation(pointing, gridded_timestamp, station)
                         if elevation < min_elevation.rad:
                             # constraint not met. update result, and do early exit.