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Parameter tweaks in PSQT and NMP

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This patch is a combinaison of two parameters tweaks patches which
have failed as strong yellows at LTC recently, by Alain Savard (Rocky640)
and Fabian Fichter (ianfab):
  http://tests.stockfishchess.org/tests/view/5b8a71e60ebc592cf2749b1d
  http://tests.stockfishchess.org/tests/view/5b81ce3b0ebc5902bdbb6585

Passed STC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 57200 W: 12392 L: 12008 D: 32800
http://tests.stockfishchess.org/tests/view/5b8d0a5a0ebc592cf274c48f

And LTC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 37215 W: 6233 L: 5962 D: 25020
http://tests.stockfishchess.org/tests/view/5b8d56090ebc592cf274cb53

Closes https://github.com/official-stockfish/Stockfish/pull/1764

Bench: 4136116

---------------

How to continue from there?

The null move reduction formula in line 769 of search.cpp is quite convoluted
and full of mysterious magic constants at the moment, it would certainly be
nice to simplify it and/or gain more Elo from it:

```
Depth R = (  (823 + 67 * depth / ONE_PLY) / 256
           + std::min(int(eval - beta) / 200, 3)) * ONE_PLY;
```
This commit is contained in:
ElbertoOne 2018-09-03 12:15:31 +02:00 • committed by Stéphane Nicolet
parent 767c4ad1fc
commit 4bef7aa5cd
2 changed files with 9 additions and 9 deletions
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16
src/psqt.cpp
View file

@ -57,14 +57,14 @@ constexpr Score Bonus[][RANK_NB][int(FILE_NB) / 2] = {
{ S(-195,-109), S(-67,-89), S(-42,-50), S(-29,-13) }
},
{ // Bishop
{ S(-64,-58), S(-13,-31), S(-25,-37), S(-34,-19) },
{ S(-20,-34), S( 0, -9), S( 12,-14), S( 1, 4) },
{ S( -9,-23), S( 27, 0), S( 1, -3), S( 11, 16) },
{ S(-11,-26), S( 28, -3), S( 21, -5), S( 32, 16) },
{ S(-11,-26), S( 27, -4), S( 16, -7), S( 31, 14) },
{ S(-17,-24), S( 16, -2), S( -8, 0), S( 2, 13) },
{ S(-23,-34), S( -3,-10), S( 6,-12), S( -2, 6) },
{ S(-55,-55), S(-11,-32), S(-19,-36), S(-29,-17) }
{ S(-49,-58), S(- 7,-31), S(-10,-37), S(-34,-19) },
{ S(-24,-34), S( 9, -9), S( 15,-14), S( 1, 4) },
{ S( -9,-23), S( 22, 0), S( -3, -3), S( 12, 16) },
{ S( 4,-26), S( 9, -3), S( 18, -5), S( 40, 16) },
{ S( -8,-26), S( 27, -4), S( 13, -7), S( 30, 14) },
{ S(-17,-24), S( 14, -2), S( -6, 0), S( 6, 13) },
{ S(-19,-34), S(-13,-10), S( 7,-12), S(-11, 6) },
{ S(-47,-55), S( -7,-32), S(-17,-36), S(-29,-17) }
},
{ // Rook
{ S(-25, 0), S(-16, 0), S(-16, 0), S(-9, 0) },

2
src/search.cpp
View file

@ -766,7 +766,7 @@ namespace {
assert(eval - beta >= 0);
// Null move dynamic reduction based on depth and value
Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min((eval - beta) / PawnValueMg, 3)) * ONE_PLY;
Depth R = ((823 + 67 * depth / ONE_PLY) / 256 + std::min(int(eval - beta) / 200, 3)) * ONE_PLY;
ss->currentMove = MOVE_NULL;
ss->continuationHistory = &thisThread->continuationHistory[NO_PIECE][0];