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

Retire FutilityMargins[] array

Browse source 
Now we use a formula to calculate margins on the fly.

Node count has changed because we fixed a leftover when
we still where using FutilityMargins to calculate futilityValue
in the case that we had the evaluation score in TT.

Also small indentation fix.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2009-11-28 11:52:13 +01:00
parent af3dd21e90
commit c7a77dd3c0
1 changed files with 21 additions and 31 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

52
src/search.cpp
View file

@ -182,10 +182,6 @@ namespace {
// Each move futility margin is decreased
const Value IncrementalFutilityMargin = Value(0x4);
// Remaining depth: 1 ply 1.5 ply 2 ply 2.5 ply 3 ply 3.5 ply
const Value FutilityMargins[12] = { Value(0x100), Value(0x120), Value(0x200), Value(0x220), Value(0x250), Value(0x270),
// 4 ply 4.5 ply 5 ply 5.5 ply 6 ply 6.5 ply
Value(0x2A0), Value(0x2C0), Value(0x340), Value(0x360), Value(0x3A0), Value(0x3C0) };
// Razoring
const Depth RazorDepth = 4*OnePly;
@ -1359,7 +1355,7 @@ namespace {
if (tte && ok_to_use_TT(tte, depth, beta, ply))
{
ss[ply].currentMove = ttMove; // can be MOVE_NONE
ss[ply].currentMove = ttMove; // Can be MOVE_NONE
return value_from_tt(tte->value(), ply);
}
@ -1445,18 +1441,13 @@ namespace {
futilityValue = VALUE_NONE;
useFutilityPruning = depth < SelectiveDepth && !isCheck;
// Calculate depth dependant futility pruning parameters
const int FutilityMoveCountMargin = 3 + (1 << (3 * int(depth) / 8));
const int FutilityValueMargin = 112 * bitScanReverse32(int(depth) * int(depth) / 2);
// Avoid calling evaluate() if we already have the score in TT
if (tte && (tte->type() & VALUE_TYPE_EVAL))
futilityValue = value_from_tt(tte->value(), ply) + FutilityMargins[int(depth) - 2];
// Move count pruning limit
const int MCLimit = 3 + (1 << (3*int(depth)/8));
/*
for (int d = 2; d < 16; d++)
std::cout << d << " -> " << 56*(0+2*bitScanReverse32(1 * int(d) * int(d) / 2)) << std::endl;
//std::cout << d << " -> " << 32*(1+3*bitScanReverse32(1 * int(d) * int(d))) << std::endl;
*/
futilityValue = value_from_tt(tte->value(), ply) + FutilityValueMargin;
// Loop through all legal moves until no moves remain or a beta cutoff occurs
while ( bestValue < beta
@ -1512,17 +1503,16 @@ namespace {
&& move != ttMove)
{
// History pruning. See ok_to_prune() definition
if ( moveCount >= MCLimit
if ( moveCount >= FutilityMoveCountMargin
&& ok_to_prune(pos, move, ss[ply].threatMove, depth)
&& bestValue > value_mated_in(PLY_MAX))
continue;
// Value based pruning
if (approximateEval < beta)
{//dbg_before();
{
if (futilityValue == VALUE_NONE)
futilityValue = evaluate(pos, ei, threadID)
+ 56*(0+2*bitScanReverse32(1 * int(depth) * int(depth) / 2));
futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin;
futilityValueScaled = futilityValue - moveCount * IncrementalFutilityMargin;
@ -1532,7 +1522,6 @@ namespace {
bestValue = futilityValueScaled;
continue;
}
//dbg_after(); // 36% (inc == 8), 40% (inc == 4), 37%(56)
}
}
@ -1552,7 +1541,7 @@ namespace {
value = -search(pos, ss, -(beta-1), newDepth-OnePly, ply+1, true, threadID);
}
else
value = beta; // Just to trigger next condition
value = beta; // Just to trigger next condition
if (value >= beta) // Go with full depth non-pv search
{
@ -1566,12 +1555,12 @@ namespace {
// New best move?
if (value > bestValue)
{
bestValue = value;
if (value >= beta)
update_pv(ss, ply);
bestValue = value;
if (value >= beta)
update_pv(ss, ply);
if (value == value_mate_in(ply + 1))
ss[ply].mateKiller = move;
if (value == value_mate_in(ply + 1))
ss[ply].mateKiller = move;
}
// Split?
@ -1584,7 +1573,7 @@ namespace {
&& !thread_should_stop(threadID)
&& split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, approximateEval,
depth, &moveCount, &mp, threadID, false))
break;
break;
}
// All legal moves have been searched. A special case: If there were
@ -1663,10 +1652,10 @@ namespace {
}
ttMove = (tte ? tte->move() : MOVE_NONE);
// Evaluate the position statically
isCheck = pos.is_check();
ei.futilityMargin = Value(0); // Manually initialize futilityMargin
// Evaluate the position statically
if (isCheck)
staticValue = -VALUE_INFINITE;
@ -1675,7 +1664,7 @@ namespace {
// Use the cached evaluation score if possible
assert(ei.futilityMargin == Value(0));
staticValue = tte->value();
staticValue = value_from_tt(tte->value(), ply);
}
else
staticValue = evaluate(pos, ei, threadID);
@ -1820,6 +1809,8 @@ namespace {
bool useFutilityPruning = sp->depth < SelectiveDepth
&& !isCheck;
const int FutilityValueMargin = 112 * bitScanReverse32(int(sp->depth) * int(sp->depth) / 2);
while ( sp->bestValue < sp->beta
&& !thread_should_stop(threadID)
&& (move = sp->mp->get_next_move(sp->lock)) != MOVE_NONE)
@ -1857,8 +1848,7 @@ namespace {
if (sp->futilityValue == VALUE_NONE)
{
EvalInfo ei;
sp->futilityValue = evaluate(pos, ei, threadID)
+ FutilityMargins[int(sp->depth) - 2];
sp->futilityValue = evaluate(pos, ei, threadID) + FutilityValueMargin;
}
if (sp->futilityValue < sp->beta)