Tweak NMP for losing chess variants

giveaway STC
LLR: 2.97 (-2.94,2.94) [0.00,10.00]
Total: 1258 W: 535 L: 434 D: 289
http://www.variantfishtest.org:6543/tests/view/600d9fc86e23db077dd66206

giveaway LTC
LLR: 2.97 (-2.94,2.94) [0.00,10.00]
Total: 1975 W: 756 L: 650 D: 569
http://www.variantfishtest.org:6543/tests/view/600daa4d6e23db077dd6620f

diff --git a/src/search.cpp b/src/search.cpp
index 776bd84..ed725fe 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -943,7 +943,7 @@ namespace {
         assert(eval - beta >= 0);
 
         // Null move dynamic reduction based on depth and value
-        Depth R = (1015 - 300 * pos.must_capture() - 250 * !pos.checking_permitted() + 85 * depth) / 256 + std::min(int(eval - beta) / 191, 3);
+        Depth R = (1015 - 300 * pos.must_capture() - 250 * !pos.checking_permitted() + 85 * depth) / 256 + std::min(int(eval - beta) / (191 + 200 * pos.must_capture()), 3);
 
         ss->currentMove = MOVE_NULL;
         ss->continuationHistory = &thisThread->continuationHistory[0][0][NO_PIECE][0];