kate/BadFish
1
0
Fork 0
mirror of https://github.com/sockspls/badfish synced 2025-07-11 19:49:14 +00:00
Code Issues Releases Wiki Activity

Add comments to probCut code

Browse source 
and rename a variable

closes https://github.com/official-stockfish/Stockfish/pull/2819

No functional change
This commit is contained in:
Vizvezdenec 2020-07-18 16:30:00 +03:00 • committed by Joost VandeVondele
parent 220ef1d27d
commit a72cec1ff8
1 changed files with 20 additions and 13 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

33
src/search.cpp
View file

@ -596,7 +596,7 @@ namespace {
Key posKey; Key posKey;
Move ttMove, move, excludedMove, bestMove; Move ttMove, move, excludedMove, bestMove;
Depth extension, newDepth; Depth extension, newDepth;
Value bestValue, value, ttValue, eval, maxValue, probcutBeta; Value bestValue, value, ttValue, eval, maxValue, probCutBeta;
bool ttHit, ttPv, formerPv, givesCheck, improving, didLMR, priorCapture; bool ttHit, ttPv, formerPv, givesCheck, improving, didLMR, priorCapture;
bool captureOrPromotion, doFullDepthSearch, moveCountPruning, bool captureOrPromotion, doFullDepthSearch, moveCountPruning,
ttCapture, singularQuietLMR; ttCapture, singularQuietLMR;
@ -871,7 +871,7 @@ namespace {
} }
} }
probcutBeta = beta + 176 - 49 * improving; probCutBeta = beta + 176 - 49 * improving;
// Step 10. ProbCut (~10 Elo) // Step 10. ProbCut (~10 Elo)
// If we have a good enough capture and a reduced search returns a value // If we have a good enough capture and a reduced search returns a value
@ -879,21 +879,27 @@ namespace {
if ( !PvNode if ( !PvNode
&& depth > 4 && depth > 4
&& abs(beta) < VALUE_TB_WIN_IN_MAX_PLY && abs(beta) < VALUE_TB_WIN_IN_MAX_PLY
&& !( ttHit // if value from transposition table is lower than probCutBeta, don't attempt probCut
&& tte->depth() >= depth - 3 // there and in further interactions with transposition table cutoff depth is set to depth - 3
// because probCut search has depth set to depth - 4 but we also do a move before it
// so effective depth is equal to depth - 3
&& !( ttHit
&& tte->depth() >= depth - 3
&& ttValue != VALUE_NONE && ttValue != VALUE_NONE
&& ttValue < probcutBeta)) && ttValue < probCutBeta))
{ {
// if ttMove is a capture and value from transposition table is good enough produce probCut
// cutoff without digging into actual probCut search
if ( ttHit if ( ttHit
&& tte->depth() >= depth - 3 && tte->depth() >= depth - 3
&& ttValue != VALUE_NONE && ttValue != VALUE_NONE
&& ttValue >= probcutBeta && ttValue >= probCutBeta
&& ttMove && ttMove
&& pos.capture_or_promotion(ttMove)) && pos.capture_or_promotion(ttMove))
return probcutBeta; return probCutBeta;
assert(probcutBeta < VALUE_INFINITE); assert(probCutBeta < VALUE_INFINITE);
MovePicker mp(pos, ttMove, probcutBeta - ss->staticEval, &captureHistory); MovePicker mp(pos, ttMove, probCutBeta - ss->staticEval, &captureHistory);
int probCutCount = 0; int probCutCount = 0;
while ( (move = mp.next_move()) != MOVE_NONE while ( (move = mp.next_move()) != MOVE_NONE
@ -915,16 +921,17 @@ namespace {
pos.do_move(move, st); pos.do_move(move, st);
// Perform a preliminary qsearch to verify that the move holds // Perform a preliminary qsearch to verify that the move holds
value = -qsearch<NonPV>(pos, ss+1, -probcutBeta, -probcutBeta+1); value = -qsearch<NonPV>(pos, ss+1, -probCutBeta, -probCutBeta+1);
// If the qsearch held, perform the regular search // If the qsearch held, perform the regular search
if (value >= probcutBeta) if (value >= probCutBeta)
value = -search<NonPV>(pos, ss+1, -probcutBeta, -probcutBeta+1, depth - 4, !cutNode); value = -search<NonPV>(pos, ss+1, -probCutBeta, -probCutBeta+1, depth - 4, !cutNode);
pos.undo_move(move); pos.undo_move(move);
if (value >= probcutBeta) if (value >= probCutBeta)
{ {
// if transposition table doesn't have equal or more deep info write probCut data into it
if ( !(ttHit if ( !(ttHit
&& tte->depth() >= depth - 3 && tte->depth() >= depth - 3
&& ttValue != VALUE_NONE)) && ttValue != VALUE_NONE))