Loosened trigger condition for king safety

Ralph Stößer · mcostalba · commit 899a2c033e2e · 2013-12-23T20:55:30.000+01:00
Reduce eval discontinuity becuase now we kick in
king safety evaluation in many more cases.

Passed both short TC:
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 8708 W: 1742 L: 1613 D: 5353

And long TC:
LLR: 2.95 (-2.94,2.94) [0.00,6.00]
Total: 6743 W: 1122 L: 990 D: 4631

bench: 6835416
diff --git a/src/evaluate.cpp b/src/evaluate.cpp
@@ -640,8 +640,7 @@ Value do_evaluate(const Position& pos) {
     Score score = ei.pi->king_safety<Us>(pos, ksq);
 
     // Main king safety evaluation
-    if (   ei.kingAttackersCount[Them] >= 2
-        && ei.kingAdjacentZoneAttacksCount[Them])
+    if (ei.kingAttackersCount[Them])
     {
         // Find the attacked squares around the king which have no defenders
         // apart from the king itself

Original file line number	Diff line number	Diff line change
`@@ -640,8 +640,7 @@ Value do_evaluate(const Position& pos) {`
`640`	`640`	`Score score = ei.pi->king_safety<Us>(pos, ksq);`
`641`	`641`
`642`	`642`	`// Main king safety evaluation`
`643`		`- if ( ei.kingAttackersCount[Them] >= 2`
`644`		`- && ei.kingAdjacentZoneAttacksCount[Them])`
	`643`	`+ if (ei.kingAttackersCount[Them])`
`645`	`644`	`{`
`646`	`645`	`// Find the attacked squares around the king which have no defenders`
`647`	`646`	`// apart from the king itself`