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Revert "Extend full 3 fold detection to PvNodes"

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This commit is contained in:
Marco Costalba
2013-01-28 17:24:01 +01:00
parent 483c98a69e
commit 58c9fbacc7
3 changed files with 18 additions and 14 deletions
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24
src/position.cpp
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@@ -1363,31 +1363,36 @@ Value Position::compute_non_pawn_material(Color c) const {
/// Position::is_draw() tests whether the position is drawn by material,
/// repetition, or the 50 moves rule. It does not detect stalemates, this
/// must be done by the search.
template<bool CheckRepetition, bool CheckThreeFold>
template<bool SkipRepetition>
bool Position::is_draw() const {
// Draw by material?
if ( !pieces(PAWN)
&& (non_pawn_material(WHITE) + non_pawn_material(BLACK) <= BishopValueMg))
return true;
// Draw by the 50 moves rule?
if (st->rule50 > 99 && (!checkers() || MoveList<LEGAL>(*this).size()))
return true;
if (CheckRepetition)
// Draw by repetition?
if (!SkipRepetition)
{
int i = 4, e = std::min(st->rule50, st->pliesFromNull), cnt;
int i = 4, e = std::min(st->rule50, st->pliesFromNull);
if (i <= e)
{
StateInfo* stp = st->previous->previous;
for (cnt = 0; i <= e; i += 2)
{
do {
stp = stp->previous->previous;
if (stp->key == st->key && (!CheckThreeFold || ++cnt >= 2))
if (stp->key == st->key)
return true;
}
i += 2;
} while (i <= e);
}
}
@@ -1395,9 +1400,8 @@ bool Position::is_draw() const {
}
// Explicit template instantiations
template bool Position::is_draw<true, true>() const;
template bool Position::is_draw<true, false>() const;
template bool Position::is_draw<false,false>() const;
template bool Position::is_draw<false>() const;
template bool Position::is_draw<true>() const;
/// Position::flip() flips position with the white and black sides reversed. This