Actually, this bit is superfluous.

Author: Wood, Tony

py/orbit/bunch_utils/collect_bunch.py

@@ -146,16 +146,10 @@ def collect_bunch(
         for attr in bunch.bunchAttrIntNames():
             bunch_dict["attributes"][attr] = np.int32(bunch.bunchAttrInt(attr))
 
-        _fill_and_flush_memmap(coords_memmap, bunch, start_row, local_rows)
-
-        if mpi_size == 1:
-            coords_memmap = np.memmap(fname, dtype=dtype, mode="r", shape=coords_shape)
-            bunch_dict["coords"] = np.array(coords_memmap)
-            return bunch_dict
-
     orbit_mpi.MPI_Barrier(mpi_comm)
 
-    coords_memmap = np.memmap(fname, dtype=dtype, mode="r+", shape=coords_shape)
+    if mpi_rank != 0:
+        coords_memmap = np.memmap(fname, dtype=dtype, mode="r+", shape=coords_shape)
 
     _fill_and_flush_memmap(coords_memmap, bunch, start_row, local_rows)