-o Buffer sizing in internal sorters.
-o Switching between direct and normal I/O.
-o When merging, choose the output file with less runs instead of always switching?
-o Implement multi-way merge.
-o Mode with only 2-way unification?
-o Speed up 2-way merge.
-o Speed up radix splitting.
-o A debug switch for disabling the presorter.
-o Deal with too rough range estimates in radix splitting.
+o Clean up log levels.
+o Clean up introductory comments.
+o Log messages should show both original and new size of the data. The speed
+ should be probably calculated from the former.
+o Automatically tune ASORT_MIN_RADIX, ASORT_MIN_SHIFT and especially ASORT_RADIX_BITS.
+o Buffer sizing in shep-export.
+
+Improvements:
+o Switching between direct and normal I/O. Should use normal I/O if the input is small enough.
+o How does the speed of radix splitting decrease with increasing number of hash bits?
+ Does it help to use more bits than we need, so that we sort less data in memory?
+
+Users of lib/sorter/array.h which might use radix-sorting:
+indexer/chewer.c
+indexer/lexfreq.c
+indexer/mkgraph.c
+indexer/reftexts.c