Added the possibility to compress tables to 2 bits per entry.

This is done similarly to nxopt: one base value is selected and entries
are memorized based on that base value. Values higher than base+3
are returned as base+3 (still a valid estimate) and values lower
or equal to base require a lookup on a "fallback" table, which
must give a valid estimate for the larger one (e.g. nxopt31 or khuge
can fallback to drud_sym16).
I have also added some info to the pruning table files: base value and
distribution. Unfortunately this means that everyone who has used nissy
2.0beta has to re-generate the tables.

1 files changed, 4 insertions, 4 deletions

diff --git a/src/symcoord.c b/src/symcoord.c
index 8b0eeb4..cb178b7 100644
--- a/src/symcoord.c
+++ b/src/symcoord.c
@@ -166,8 +166,8 @@ antindex_nxopt31(uint64_t ind)
         Cube c;
 
         c = antindex_eofbepos_sym16(ind/(BINOM8ON4*POW3TO7));
-        c.cp = coord_cpud_separate.cube((ind/POW3TO7)%BINOM8ON4).cp;
-        c.coud = ind % POW3TO7;
+        c.cp = coord_cpud_separate.cube(ind % BINOM8ON4).cp;
+        c.coud = (ind / BINOM8ON4) % POW3TO7;
 
         return c;
 }
@@ -231,9 +231,9 @@ index_nxopt31(Cube cube)
 
         t = sd_eofbepos_16.transtorep[coord_eofbepos.index(cube)];
         c = apply_trans(t, cube);
-        a = (index_eofbepos_sym16(c)*BINOM8ON4) + coord_cpud_separate.index(c);
+        a = (index_eofbepos_sym16(c)*POW3TO7) + c.coud;
 
-        return a * POW3TO7 + c.coud;
+        return a * BINOM8ON4 + coord_cpud_separate.index(c);
 }
 
 static int