5.11.7 Simplify mobility eval. Rank seven.

Oliver Brausch · Oliver Brausch · commit 1c45d5e25a7a · 2025-07-12T15:46:01.000+02:00
diff --git a/src/Readme.txt b/src/Readme.txt
@@ -1,6 +1,6 @@
-OliThink5 (c) Oliver Brausch 03.Jul.2025, ob112@web.de, http://brausch.org
+OliThink5 (c) Oliver Brausch 12.Jul.2025, ob112@web.de, http://brausch.org
 
-Version: 5.11.6
+Version: 5.11.7
 Protocol: CECP v2 (winboard/xboard)
 HashSize: 128MB
 Ponder: Yes
@@ -9,10 +9,13 @@ EndgameTables: No
 AnalyzeMode: Basic
 SearchMethods: Nullmove, Internal Iterative Reduction, Check Extension, LMR
 Evaluation: Just mobility and a very simple pawnprogressing evaluation
-LinesOfCode: 1295
+LinesOfCode: 1294
 Stability: 100%
 Special thanks to Dann Corbit for his support and contribution.
 
+v5.11.7: changes since 5.11.6:
+Simplify mobility eval. Rank seven.
+
 v5.11.6: changes since 5.11.5:
 Unify pick method. Reduce code. SEE refactor. Use local occupied. Corner eval for king.
 
diff --git a/src/olithink.c b/src/olithink.c
@@ -1,5 +1,5 @@
-#define VER "5.11.6"
-/* OliThink5 (c) Oliver Brausch 03.Juk.2025, ob112@web.de, http://brausch.org */
+#define VER "5.11.7"
+/* OliThink5 (c) Oliver Brausch 12.Jul.2025, ob112@web.de, http://brausch.org */
 #include <stdio.h>
 #include <string.h>
 #ifdef _WIN64
@@ -717,12 +717,12 @@ int kmobilf(int c) {
 	return sfo < 14 ? km : km * (16 - sfo) /4;
 }
 
-#define MOBILITY(a, mb) (bitcnt(a) + bitcnt(a & mb) + bitcnt(a & mb & centr2))
+#define MOBILITY(a, mb) (bitcnt(a) + bitcnt(a & mb) + bitcnt(a & mb & c3))
 /* The eval for Color c. It's almost only mobility. */
 int evalc(int c) {
 	int f, mn = 0, katt = 0, oc = c^1, egf = 10400/(80 + P.sf[c] + P.sf[oc]) + randm;
 	u64 b, a, cb = P.color[c], ocb = P.color[oc], occ = BOARD, mb = mobilityb(c, occ) & centr;
-	u64 kn = kmoves[P.king[oc]] & (~P.piece[PAWN]);
+	u64 kn = kmoves[P.king[oc]] & (~P.piece[PAWN]), c3 = centr2 | rankb[c ? 1 : 6];
 
 	b = P.piece[PAWN] & cb;
 	while (b) {
@@ -751,7 +751,7 @@ int evalc(int c) {
 	}
 
 	occ ^= BIT[P.king[oc]]; //Opposite King doesn't block mobility at all
-	occ ^= P.piece[QUEEN] & cb; //Own Queen doesn't block mobility for anybody.
+	occ ^= P.piece[QUEEN]; //Queens don't block mobility for anybody.
 	b = P.piece[QUEEN] & cb;
 	while (b) {
 		f = pullLsb(&b);
@@ -760,7 +760,7 @@ int evalc(int c) {
 		mn += MOBILITY(a, mb) * egf * egf / 80 / 80;
 	}
 
-	occ ^= RQU & ocb; //Opposite Queen & Rooks don't block mobility for bishop
+	occ ^= P.piece[ROOK]; //Rooks don't block mobility for bishop
 	b = P.piece[BISHOP] & cb;
 	while (b) {
 		f = pullLsb(&b);
@@ -769,7 +769,6 @@ int evalc(int c) {
 		mn += MOBILITY(a, mb) << 2;
 	}
 
-	occ ^= P.piece[ROOK]; //Own Rooks and opposite Queen don't block mobility for rook
 	b = P.piece[ROOK] & cb;
 	while (b) {
 		f = pullLsb(&b);
