JP-3521: Fix jump multiprocessing error

CHANGES.rst

@@ -86,6 +86,9 @@ jump
 - Added more allowable selections for the number of cores to use for
   multiprocessing [#183].
 
+- Fixed the numer of rows per slice in multiprocessing that lead to
+  different results when running the step with multiprocess [#239]
+
 ramp_fitting
 ~~~~~~~~~~~~
 

src/stcal/jump/jump.py

@@ -314,7 +314,7 @@
             log.info("Total showers= %i", num_showers)
             number_extended_events = num_showers
     else:
-        yinc = int(n_rows / n_slices)
+        yinc = int(n_rows // n_slices)
         slices = []
         # Slice up data, gdq, readnoise_2d into slices
         # Each element of slices is a tuple of
@@ -427,6 +427,13 @@
             # save the neighbors to be flagged that will be in the next slice
             previous_row_above_gdq = row_above_gdq.copy()
             k += 1
+            # remove redundant bits in pixels that have jump flagged but were
+            # already flagged as do_not_use or saturated.
+            gdq[gdq == np.bitwise_or(dqflags['DO_NOT_USE'], dqflags['JUMP_DET'])] = \
+                dqflags['DO_NOT_USE']
+            gdq[gdq == np.bitwise_or(dqflags['SATURATED'], dqflags['JUMP_DET'])] = \
+                dqflags['SATURATED']
+
         #  This is the flag that controls the flagging of snowballs.
         if expand_large_events:
             total_snowballs = flag_large_events(