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Remove history counters

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Instead decrement history value on failure.

After 999 games at 1+0

Mod vs Orig  +236 =558 -204 51.60% +11 ELO

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2009-12-09 14:40:38 +01:00
parent 7bc72d092f
commit 2161d8b0b3
3 changed files with 13 additions and 33 deletions
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21
src/history.cpp
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@@ -42,8 +42,6 @@ History::History() { clear(); }
void History::clear() {
memset(history, 0, 2 * 8 * 64 * sizeof(int));
memset(successCount, 0, 2 * 8 * 64 * sizeof(int));
memset(failureCount, 0, 2 * 8 * 64 * sizeof(int));
}
@@ -58,7 +56,6 @@ void History::success(Piece p, Square to, Depth d) {
assert(square_is_ok(to));
history[p][to] += int(d) * int(d);
successCount[p][to]++;
// Prevent history overflow
if (history[p][to] >= HistoryMax)
@@ -72,12 +69,14 @@ void History::success(Piece p, Square to, Depth d) {
/// called for each non-capturing move which failed to produce a beta cutoff
/// at a node where a beta cutoff was finally found.
void History::failure(Piece p, Square to) {
void History::failure(Piece p, Square to, Depth d) {
assert(piece_is_ok(p));
assert(square_is_ok(to));
failureCount[p][to]++;
history[p][to] -= int(d) * int(d);
if (history[p][to] < 0)
history[p][to] = 0;
}
@@ -91,15 +90,3 @@ int History::move_ordering_score(Piece p, Square to) const {
return history[p][to];
}
/// History::ok_to_prune() decides whether a move has been sufficiently
/// unsuccessful that it makes sense to prune it entirely.
bool History::ok_to_prune(Piece p, Square to, Depth d) const {
assert(piece_is_ok(p));
assert(square_is_ok(to));
return (int(d) * successCount[p][to] < failureCount[p][to]);
}