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Allow full repetition detection

Based on sshivaji 6ee19aa5389ce60181907ba53bbb50642f2d5657 commit
This commit is contained in:
Jean-Francois Romang 2012-10-23 20:33:45 +00:00
parent c1f4000426
commit 0587c5b605
3 changed files with 13 additions and 9 deletions

View file

@ -1467,7 +1467,7 @@ 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 SkipRepetition>
template<bool SkipRepetition, bool SkipThreeFoldCheck>
bool Position::is_draw() const {
// Draw by material?
@ -1482,7 +1482,7 @@ bool Position::is_draw() const {
// Draw by repetition?
if (!SkipRepetition)
{
int i = 4, e = std::min(st->rule50, st->pliesFromNull);
int i = 4, e = std::min(st->rule50, st->pliesFromNull), rep_count=0;
if (i <= e)
{
@ -1492,7 +1492,10 @@ bool Position::is_draw() const {
stp = stp->previous->previous;
if (stp->key == st->key)
return true;
{
if(SkipThreeFoldCheck) return true;
else if(++rep_count>=2) return true;
}
i +=2;
@ -1504,8 +1507,9 @@ bool Position::is_draw() const {
}
// Explicit template instantiations
template bool Position::is_draw<false>() const;
template bool Position::is_draw<true>() const;
template bool Position::is_draw<false,true>() const;
template bool Position::is_draw<true,true>() const;
template bool Position::is_draw<false,false>() const;
/// Position::flip() flips position with the white and black sides reversed. This

View file

@ -183,7 +183,7 @@ public:
Thread* this_thread() const;
int64_t nodes_searched() const;
void set_nodes_searched(int64_t n);
template<bool SkipRepetition> bool is_draw() const;
template<bool SkipRepetition, bool SkipThreeFoldCheck> bool is_draw() const;
// Position consistency check, for debugging
bool pos_is_ok(int* failedStep = NULL) const;

View file

@ -524,7 +524,7 @@ namespace {
if (!RootNode)
{
// Step 2. Check for aborted search and immediate draw
if (Signals.stop || pos.is_draw<false>() || ss->ply > MAX_PLY)
if (Signals.stop || pos.is_draw<false,true>() || ss->ply > MAX_PLY)
return DrawValue[pos.side_to_move()];
// Step 3. Mate distance pruning. Even if we mate at the next move our score
@ -1103,7 +1103,7 @@ split_point_start: // At split points actual search starts from here
ss->ply = (ss-1)->ply + 1;
// Check for an instant draw or maximum ply reached
if (pos.is_draw<true>() || ss->ply > MAX_PLY)
if (pos.is_draw<true,true>() || ss->ply > MAX_PLY)
return DrawValue[pos.side_to_move()];
// Transposition table lookup. At PV nodes, we don't use the TT for
@ -1552,7 +1552,7 @@ void RootMove::extract_pv_from_tt(Position& pos) {
&& pos.is_pseudo_legal(m)
&& pos.pl_move_is_legal(m, pos.pinned_pieces())
&& ply < MAX_PLY
&& (!pos.is_draw<false>() || ply < 2))
&& (!pos.is_draw<false,true>() || ply < 2))
{
pv.push_back(m);
pos.do_move(m, *st++);