Improve TT replacement scheme (#180)

Aryan1508 · Aryan1508 · commit 2499766f7eb4 · 2021-08-06T19:11:32.000+05:30
ELO   | 8.88 +- 5.80 (95%)
SPRT  | 8.0+0.08s Threads=1 Hash=2MB
LLR   | 3.09 (-2.94, 2.94) [0.00, 5.00]
GAMES | N: 7200 W: 1974 L: 1790 D: 3436

Bench: 5557233
diff --git a/src/tt.cpp b/src/tt.cpp
@@ -39,7 +39,7 @@ void TTable::add(Position const &position, Move move, int16_t score, uint8_t dep
     uint64_t hash = position.get_key();
     uint64_t index = hash % entries.size(); 
 
-    if (flag != TEFlag::exact && hash == entries[index].hash && depth < entries[index].depth) return;
+    if (flag != TEFlag::exact && hash == entries[index].hash && depth < entries[index].depth - 1) return;
 
     if (flag == TEFlag::exact || depth * 3 > entries[index].depth)
         entries[index] = TEntry(hash, score, move, depth, flag, seval);
diff --git a/src/uci.cpp b/src/uci.cpp
@@ -27,7 +27,7 @@
 #include "polyglot.h"
 #include <cstring>
 
-const char *version = "8.36";
+const char *version = "8.37";
 
 namespace
 {

Original file line number	Diff line number	Diff line change
`@@ -27,7 +27,7 @@`
`27`	`27`	`#include "polyglot.h"`
`28`	`28`	`#include <cstring>`
`29`	`29`
`30`		`-const char *version = "8.36";`
	`30`	`+const char *version = "8.37";`
`31`	`31`
`32`	`32`	`namespace`
`33`	`33`	`{`