BUG FIX: Updated get_turnaround_flags so that it can catch stationary…

sotodlib/preprocess/processes.py

@@ -1510,7 +1510,8 @@ def calc_and_save(self, aman, proc_aman):
             calc_aman.wrap('turnarounds', ta, [(0, 'dets'), (1, 'samps')])
 
         if ('merge_subscans' not in self.calc_cfgs) or (self.calc_cfgs['merge_subscans']):
-            calc_aman.wrap('subscan_info', aman.subscan_info)
+            if hasattr(aman, 'subscan_info'):
+                calc_aman.wrap('subscan_info', aman.subscan_info)
 
         self.save(proc_aman, calc_aman)
         return aman, proc_aman
@@ -1526,6 +1527,19 @@ def process(self, aman, proc_aman, sim=False, data_aman=None):
             raise NotImplementedError("No support for using data AxisManager in process")
         tod_ops.flags.get_turnaround_flags(aman, **self.process_cfgs)
         return aman, proc_aman
+
+    def select(self, meta, proc_aman=None, in_place=True):
+        if self.select_cfgs is None:
+            return meta
+        if proc_aman is None:
+            proc_aman = meta.preprocess
+
+        ta = proc_aman[self.save_name].turnarounds
+
+        if np.all(count_cuts(ta) == 0):
+            meta.restrict('dets', meta.dets.vals[:0])
+
+        return meta
 
 class SubPolyf(_Preprocess):
     """Fit TOD in each subscan with polynominal of given order and subtract it.

sotodlib/tod_ops/flags.py

@@ -157,7 +157,8 @@ def get_det_bias_flags(aman, detcal=None, rfrac_range=(0.1, 0.7),
 def get_turnaround_flags(aman, az=None, method='scanspeed', name='turnarounds',
                          merge=True, merge_lr=True, overwrite=True, 
                          t_buffer=2., kernel_size=400, peak_threshold=0.1, rel_distance_peaks=0.3,
-                         truncate=False, qlim=1, merge_subscans=True, turnarounds_in_subscan=False):
+                         truncate=False, qlim=1, merge_subscans=True, turnarounds_in_subscan=False,
+                         az_throw_threshold=0.):
     """
     Compute turnaround flags for a dataset.
 
@@ -195,6 +196,8 @@ def get_turnaround_flags(aman, az=None, method='scanspeed', name='turnarounds',
         (Optional). Also merge an AxisManager with subscan information.
     turnarounds_in_subscan : bool
         (Optional). Turnarounds are included as part of a subscan.
+    az_throw_threshold : float
+        (Optional). Minimum azimuth throw required to attempt turnaround flagging. Returns no turnarounds if below threshold.
 
     Returns
     -------
@@ -203,6 +206,18 @@ def get_turnaround_flags(aman, az=None, method='scanspeed', name='turnarounds',
     """
     if az is None : 
         az = aman.boresight.az
+
+    # Get the throw (convert to degrees).
+    az_throw = np.ptp(az) * 90 / np.pi
+
+    # If the throw is below the threshold, just output empty flags
+    if az_throw < az_throw_threshold:
+        ta_flag = Ranges.from_bitmask(np.zeros(aman.samps.count, dtype=bool))
+        ta_exp = RangesMatrix([ta_flag for i in range(aman.dets.count)])
+        if method == 'scanspeed':
+            return ta_exp, ta_exp, ta_exp
+        return ta_exp
+
 
     if method not in ['az', 'scanspeed']:
         raise ValueError('Unsupported method. Supported methods are `az` or `scanspeed`')
@@ -1237,4 +1252,4 @@ def get_good_distribution_flags(aman, param_name='wn_signal',
                     det_mask[aman[param_name] >= np.nanmax(distributions)] = False
                 else:
                     det_mask[aman[param_name] <= np.nanmin(distributions)] = False
-    return det_mask
+    return det_mask