Additional extension when score is better.

alcides-schulz · alcides-schulz · commit e407921c7055 · 2024-06-21T08:41:56.000-04:00
60s+0.6
Score of tucanoNEW vs tucanoOLD: 1024 - 948 - 2556  [0.508] 4528
Elo difference: 5.8 +/- 6.7, LOS: 95.6 %, DrawRatio: 56.4 %
SPRT: llr 2.95 (100.3%), lbound -2.94, ubound 2.94 - H1 was accepted
diff --git a/src/main.c b/src/main.c
@@ -20,7 +20,7 @@
 
 #define ENGINE "Tucano"
 #define AUTHOR "Alcides Schulz"
-#define VERSION "11.19"
+#define VERSION "11.20"
 
 void        develop_workbench(void);
 double      bench(int depth, int print);
diff --git a/src/search.c b/src/search.c
@@ -209,16 +209,21 @@ int search(GAME *game, UINT incheck, int alpha, int beta, int depth, MOVE exclud
                     int reduced_beta = trans_score - 4 * depth;
                     int singular_score = search(game, incheck, reduced_beta - 1, reduced_beta, depth / 2, move);
                     if (game->search.abort) return 0;
-                    if (singular_score < reduced_beta) {
-                        extensions = 1;
+                    if (singular_score + 50 < reduced_beta) {
+                        extensions = 2;
                     }
                     else {
-                        if (reduced_beta >= beta) {
-                            return reduced_beta;
+                        if (singular_score < reduced_beta) {
+                            extensions = 1;
                         }
                         else {
-                            if (trans_score <= alpha || trans_score >= beta) {
-                                reductions = 1;
+                            if (reduced_beta >= beta) {
+                                return reduced_beta;
+                            }
+                            else {
+                                if (trans_score <= alpha || trans_score >= beta) {
+                                    reductions = 1;
+                                }
                             }
                         }
                     }

Original file line number	Diff line number	Diff line change
`@@ -209,16 +209,21 @@ int search(GAME *game, UINT incheck, int alpha, int beta, int depth, MOVE exclud`
`209`	`209`	`int reduced_beta = trans_score - 4 * depth;`
`210`	`210`	`int singular_score = search(game, incheck, reduced_beta - 1, reduced_beta, depth / 2, move);`
`211`	`211`	`if (game->search.abort) return 0;`
`212`		`- if (singular_score < reduced_beta) {`
`213`		`- extensions = 1;`
	`212`	`+ if (singular_score + 50 < reduced_beta) {`
	`213`	`+ extensions = 2;`
`214`	`214`	`}`
`215`	`215`	`else {`
`216`		`- if (reduced_beta >= beta) {`
`217`		`- return reduced_beta;`
	`216`	`+ if (singular_score < reduced_beta) {`
	`217`	`+ extensions = 1;`
`218`	`218`	`}`
`219`	`219`	`else {`
`220`		`- if (trans_score <= alpha \|\| trans_score >= beta) {`
`221`		`- reductions = 1;`
	`220`	`+ if (reduced_beta >= beta) {`
	`221`	`+ return reduced_beta;`
	`222`	`+ }`
	`223`	`+ else {`
	`224`	`+ if (trans_score <= alpha \|\| trans_score >= beta) {`
	`225`	`+ reductions = 1;`
	`226`	`+ }`
`222`	`227`	`}`
`223`	`228`	`}`
`224`	`229`	`}`