Re: [gnugo-devel] Reading patch

[Nando]

Gunnar wrote:
> 
> Nice.

Thanx.

> owl:179         FAIL 0 [3 R19]
> blunder:23      PASS L2 [!F4|F5|F6]
> arb:203         PASS T7 [T7]
> arb:220         PASS F7 [!F6]
> arend:3         PASS P6 [P6|Q5]

Very good.

> I haven't checked what's going on with owl:179 but the passes, in
> particular blunder:23, are quite significant.

Definitely.

Also, your recent code maintenance patch is impressive and appreciated.


I just finished testing the appended patch with following results which look
rather good to me. The breakage :

trevora:220    PASS
trevorc:1440   FAIL   the test would pass with --owl-node-limit 1250
global:4       FAIL   current CVS would also fail both tests if the owl node
global:5       FAIL   limit would be similarly increased (1250)
tactics1:101   PASS
tactics1:104   PASS

Performance impact :

- reading nodes: +0.6%
- owl nodes: +0.3%
- connection nodes: -eps


Globally, I think the patch is just logical and removes a rotational
dependency.

/nando

- try (a bit) harder in attack_either()

Index: engine/reading.c
===================================================================
RCS file: /cvsroot/gnugo/gnugo/engine/reading.c,v
retrieving revision 1.106
diff -u -r1.106 reading.c
--- engine/reading.c    22 Feb 2003 16:02:25 -0000      1.106
+++ engine/reading.c    23 Feb 2003 16:13:16 -0000
@@ -452,23 +452,48 @@
 
   /* Try (a little) harder */
   {
-    int libs[2];
-    int alibs = findlib(astr, 2, libs);
+    int alibs[2];
+    int blibs[2];
+    int alib = findlib(astr, 2, alibs);
     int defended0 = WIN;
     int defended1 = WIN;
     int other = OTHER_COLOR(color);
     /* Let's just try the case where the group with the fewest liberties
      * has only 2, and try each atari in turn.
      */
-    if (alibs == 2) {
-      if (trymove(libs[0], other, "attack_either-A", astr, EMPTY, NO_MOVE)) {
+    if (alib == 2) {
+      if (trymove(alibs[0], other, "attack_either-A", astr,
+                 EMPTY, NO_MOVE)) {
        defended0 = defend_both(astr, bstr);
        popgo();
       }
       if (defended0 
-         && trymove(libs[1], other, "attack_either-B", astr,
+         && trymove(alibs[1], other, "attack_either-B", astr,
                     EMPTY, NO_MOVE)) {
        defended1 = defend_both(astr, bstr);
+       popgo();
+      }
+    }
+    /* The second string is possibly also short in liberties.
+     * Let's try to improve the result.
+     */
+    if (defended0 > 0 && defended1 > 0
+       && findlib(bstr, 2, blibs) == 2) {
+      defended0 = gg_min(defended0, defended1);
+      defended1 = defended0;
+      if (blibs[0] != alibs[0] && blibs[0] != alibs[1]
+         && trymove(blibs[0], other, "attack_either-C", bstr,
+                    EMPTY, NO_MOVE)) {
+       int defended = defend_both(astr, bstr);
+       defended0 = gg_min(defended0, defended);
+       popgo();
+      }
+      if (defended0 
+         && blibs[1] != alibs[0] && blibs[1] != alibs[1]
+         && trymove(blibs[1], other, "attack_either-D", bstr,
+                    EMPTY, NO_MOVE)) {
+       int defended = defend_both(astr, bstr);
+       defended1 = gg_min(defended1, defended);
        popgo();
       }
     }