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Move invariant of singular ext. check out of loop

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It is almost always false.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2010-06-01 15:31:24 +01:00
parent a3819188de
commit 7903495b0a
1 changed files with 8 additions and 7 deletions
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15
src/search.cpp
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@ -1229,6 +1229,11 @@ namespace {
// Initialize a MovePicker object for the current position // Initialize a MovePicker object for the current position
MovePicker mp = MovePicker(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta)); MovePicker mp = MovePicker(pos, ttMove, depth, H, ss, (PvNode ? -VALUE_INFINITE : beta));
CheckInfo ci(pos); CheckInfo ci(pos);
bool singularExtensionNode = depth >= SingularExtensionDepth[PvNode]
&& tte && tte->move()
&& !excludedMove // Do not allow recursive singular extension search
&& is_lower_bound(tte->type())
&& tte->depth() >= depth - 3 * OnePly;
// Step 10. Loop through moves // Step 10. Loop through moves
// Loop through all legal moves until no moves remain or a beta cutoff occurs // Loop through all legal moves until no moves remain or a beta cutoff occurs
@ -1251,13 +1256,9 @@ namespace {
// Singular extension search. We extend the TT move if its value is much better than // Singular extension search. We extend the TT move if its value is much better than
// its siblings. To verify this we do a reduced search on all the other moves but the // its siblings. To verify this we do a reduced search on all the other moves but the
// ttMove, if result is lower then ttValue minus a margin then we extend ttMove. // ttMove, if result is lower then ttValue minus a margin then we extend ttMove.
if ( depth >= SingularExtensionDepth[PvNode] if ( singularExtensionNode
&& tte
&& move == tte->move() && move == tte->move()
&& !excludedMove // Do not allow recursive singular extension search && ext < OnePly)
&& ext < OnePly
&& is_lower_bound(tte->type())
&& tte->depth() >= depth - 3 * OnePly)
{ {
Value ttValue = value_from_tt(tte->value(), ply); Value ttValue = value_from_tt(tte->value(), ply);
@ -1346,12 +1347,12 @@ namespace {
value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, true, threadID); value = -search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth-ss->reduction, true, threadID);
doFullDepthSearch = (value > alpha); doFullDepthSearch = (value > alpha);
} }
ss->reduction = Depth(0); // Restore original reduction
} }
// Step 15. Full depth search // Step 15. Full depth search
if (doFullDepthSearch) if (doFullDepthSearch)
{ {
ss->reduction = Depth(0);
value = newDepth < OnePly ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, Depth(0), threadID) value = newDepth < OnePly ? -qsearch<NonPV>(pos, ss+1, -(alpha+1), -alpha, Depth(0), threadID)
: - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, true, threadID); : - search<NonPV>(pos, ss+1, -(alpha+1), -alpha, newDepth, true, threadID);