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Logarithmic LMR

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Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Joona Kiiski 2010-01-03 21:58:50 +02:00 • committed by Marco Costalba
parent 7c0679ad61
commit c99d963fa5
1 changed files with 47 additions and 13 deletions
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60
src/search.cpp
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@ -326,6 +326,13 @@ namespace {
//// Functions //// Functions
//// ////
//FIXME: HACK
static double lnArray[512];
inline double ln(int i)
{
return lnArray[i];
}
/// perft() is our utility to verify move generation is bug free. All the legal /// perft() is our utility to verify move generation is bug free. All the legal
/// moves up to given depth are generated and counted and the sum returned. /// moves up to given depth are generated and counted and the sum returned.
@ -562,8 +569,14 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
/// and initializes the split point stack and the global locks and condition /// and initializes the split point stack and the global locks and condition
/// objects. /// objects.
#include <cmath> //FIXME: HACK
void init_threads() { void init_threads() {
// FIXME: HACK!!
for (int i = 0; i < 512; i++)
lnArray[i] = log(double(i));
volatile int i; volatile int i;
#if !defined(_MSC_VER) #if !defined(_MSC_VER)
@ -1202,14 +1215,19 @@ namespace {
// Try to reduce non-pv search depth by one ply if move seems not problematic, // Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth. // if the move fails high will be re-searched at full depth.
if ( depth >= 3*OnePly if ( depth >= 3*OnePly
&& moveCount >= LMRPVMoves
&& !dangerous && !dangerous
&& !captureOrPromotion && !captureOrPromotion
&& !move_is_castle(move) && !move_is_castle(move)
&& !move_is_killer(move, ss[ply])) && !move_is_killer(move, ss[ply]))
{ {
ss[ply].reduction = OnePly; double red = ln(moveCount) * ln(depth / 2) / 3.0;
value = -search(pos, ss, -alpha, newDepth-OnePly, ply+1, true, threadID); if (red >= 1.0)
{
ss[ply].reduction = Depth(floor(red * int(OnePly)));
value = -search(pos, ss, -alpha, newDepth-ss[ply].reduction, ply+1, true, threadID);
}
else
value = alpha + 1; // Just to trigger next condition
} }
else else
value = alpha + 1; // Just to trigger next condition value = alpha + 1; // Just to trigger next condition
@ -1527,14 +1545,20 @@ namespace {
// Try to reduce non-pv search depth by one ply if move seems not problematic, // Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth. // if the move fails high will be re-searched at full depth.
if ( depth >= 3*OnePly if ( depth >= 3*OnePly
&& moveCount >= LMRNonPVMoves
&& !dangerous && !dangerous
&& !captureOrPromotion && !captureOrPromotion
&& !move_is_castle(move) && !move_is_castle(move)
&& !move_is_killer(move, ss[ply])) && !move_is_killer(move, ss[ply])
/* && move != ttMove*/)
{ {
ss[ply].reduction = OnePly; double red = ln(moveCount) * ln(depth / 2) / 1.5;
value = -search(pos, ss, -(beta-1), newDepth-OnePly, ply+1, true, threadID); if (red >= 1.0)
{
ss[ply].reduction = Depth(floor(red * int(OnePly)));
value = -search(pos, ss, -(beta-1), newDepth-ss[ply].reduction, ply+1, true, threadID);
}
else
value = beta; // Just to trigger next condition
} }
else else
value = beta; // Just to trigger next condition value = beta; // Just to trigger next condition
@ -1868,13 +1892,18 @@ namespace {
// Try to reduce non-pv search depth by one ply if move seems not problematic, // Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth. // if the move fails high will be re-searched at full depth.
if ( !dangerous if ( !dangerous
&& moveCount >= LMRNonPVMoves
&& !captureOrPromotion && !captureOrPromotion
&& !move_is_castle(move) && !move_is_castle(move)
&& !move_is_killer(move, ss[sp->ply])) && !move_is_killer(move, ss[sp->ply]))
{ {
ss[sp->ply].reduction = OnePly; double red = ln(moveCount) * ln(sp->depth / 2) / 1.5;
value = -search(pos, ss, -(sp->beta-1), newDepth - OnePly, sp->ply+1, true, threadID); if (red >= 1.0)
{
ss[sp->ply].reduction = Depth(floor(red * int(OnePly)));
value = -search(pos, ss, -(sp->beta-1), newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
}
else
value = sp->beta; // Just to trigger next condition
} }
else else
value = sp->beta; // Just to trigger next condition value = sp->beta; // Just to trigger next condition
@ -1974,13 +2003,18 @@ namespace {
// Try to reduce non-pv search depth by one ply if move seems not problematic, // Try to reduce non-pv search depth by one ply if move seems not problematic,
// if the move fails high will be re-searched at full depth. // if the move fails high will be re-searched at full depth.
if ( !dangerous if ( !dangerous
&& moveCount >= LMRPVMoves
&& !captureOrPromotion && !captureOrPromotion
&& !move_is_castle(move) && !move_is_castle(move)
&& !move_is_killer(move, ss[sp->ply])) && !move_is_killer(move, ss[sp->ply]))
{ {
ss[sp->ply].reduction = OnePly; double red = ln(moveCount) * ln(sp->depth / 2) / 3.0;
value = -search(pos, ss, -sp->alpha, newDepth - OnePly, sp->ply+1, true, threadID); if (red >= 1.0)
{
ss[sp->ply].reduction = Depth(floor(red * int(OnePly)));
value = -search(pos, ss, -sp->alpha, newDepth-ss[sp->ply].reduction, sp->ply+1, true, threadID);
}
else
value = sp->alpha + 1; // Just to trigger next condition
} }
else else
value = sp->alpha + 1; // Just to trigger next condition value = sp->alpha + 1; // Just to trigger next condition