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Use int16_t in History values 

Reduces memory footprint by ~1.2MB (per thread).

Strong pressure: small but mesurable gain
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 258430 W: 46977 L: 45943 D: 165510

Low pressure: no regression
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 73542 W: 13058 L: 13026 D: 47458

Strong pressure + LTC: elo gain confirmed
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 31489 W: 4532 L: 4295 D: 22662

Tested for crashing on overflow and after 70K
games at STC we have only 4 time losses,
possible candidate for an overflow.

No functional change.
pull/1206/merge
lucasart 2017-08-09 19:35:05 +08:00 committed by Marco Costalba
parent 232c50fed0
commit ae6a4ebf1f
1 changed files with 9 additions and 1 deletions
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10
src/movepick.h
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@ -28,7 +28,7 @@
#include "types.h"
/// StatBoards is a generic 2-dimensional array used to store various statistics
template<int Size1, int Size2, typename T = int>
template<int Size1, int Size2, typename T = int16_t>
struct StatBoards : public std::array<std::array<T, Size2>, Size1> {
void fill(const T& v) {
@ -55,6 +55,10 @@ struct ButterflyHistory : public ButterflyBoards {
auto& entry = (*this)[c][from_to(m)];
assert(abs(bonus) <= D); // Consistency check for below formula
assert([&]{
int v = entry + bonus * 32 - entry * abs(bonus) / D;
return INT16_MIN < v && v < INT16_MAX;
}());
entry += bonus * 32 - entry * abs(bonus) / D;
@ -71,6 +75,10 @@ struct PieceToHistory : public PieceToBoards {
auto& entry = (*this)[pc][to];
assert(abs(bonus) <= D); // Consistency check for below formula
assert([&]{
int v = entry + bonus * 32 - entry * abs(bonus) / D;
return INT16_MIN < v && v < INT16_MAX;
}());
entry += bonus * 32 - entry * abs(bonus) / D;