From: Fabian Fichter <ianfab@users.noreply.github.com>
Date: Fri, 19 Jul 2019 13:22:13 +0000 (+0200)
Subject: Double knight-pawn imbalance for antichess variants
X-Git-Url: http://winboard.nl/cgi-bin?a=commitdiff_plain;h=ee19d0c71d86e673e21daa0d3d366a9658373858;p=fairystockfish.git

Double knight-pawn imbalance for antichess variants

giveaway STC
LLR: 2.96 (-2.94,2.94) [0.00,10.00]
Total: 864 W: 391 L: 294 D: 179
http://35.161.250.236:6543/tests/view/5d31c47b6e23db34f4206ca3

giveaway LTC
LLR: 2.96 (-2.94,2.94) [0.00,10.00]
Total: 568 W: 260 L: 170 D: 138
http://35.161.250.236:6543/tests/view/5d31d03f6e23db34f4206cb1

losers STC
LLR: 2.97 (-2.94,2.94) [0.00,10.00]
Total: 1184 W: 591 L: 480 D: 113
http://35.161.250.236:6543/tests/view/5d31c4976e23db34f4206ca6

losers LTC
LLR: 2.95 (-2.94,2.94) [0.00,10.00]
Total: 701 W: 372 L: 268 D: 61
http://35.161.250.236:6543/tests/view/5d31d6d66e23db34f4206cb3
---

diff --git a/src/material.cpp b/src/material.cpp
index 8b29f4e..915593c 100644
--- a/src/material.cpp
+++ b/src/material.cpp
@@ -106,7 +106,7 @@ namespace {
         int v = 0;
 
         for (int pt2 = NO_PIECE_TYPE; pt2 <= pt1; ++pt2)
-            v +=  QuadraticOurs[pt1][pt2] * pieceCount[Us][pt2]
+            v +=  QuadraticOurs[pt1][pt2] * pieceCount[Us][pt2] * (pos.must_capture() && pt1 == KNIGHT && pt2 == PAWN ? 2 : 1)
                 + QuadraticTheirs[pt1][pt2] * pieceCount[Them][pt2];
 
         bonus += pieceCount[Us][pt1] * v;