Would you like to react to this message? Create an account in a few clicks or log in to continue.

Chess2uLog in

descriptionStockfish 9 EmptyStockfish 9

Stockfish 9 released.

descriptionStockfish 9 EmptyRe: Stockfish 9


descriptionStockfish 9 EmptyRe: Stockfish 9

Compiled by Alexei Chernakoff

Cfish 9 for Android

Stockfish 9 for Android

Brainfish 010218 for Android

descriptionStockfish 9 EmptyRe: Stockfish 9

Stockfish 9 for Android by Alexei Chernakoff
**This version is the same as Stockfish_9 arm7 but PGO optimized, thus calculates slightly faster

descriptionStockfish 9 EmptyRe: Stockfish 9

At last, Stockfish has Dynamic Contempt!

Author: Stefano Cardanobile
Date: Fri Feb 9 19:07:19 2018 +0100
Timestamp: 1518199639

Introduce dynamic contempt

Make contempt dependent on the current score of the root position.

The idea is that we now use a linear formula like the following to decide
on the contempt to use during a search :

contempt = x + y * eval

where x is the base contempt set by the user in the "Contempt" UCI option,
and y * eval is the dynamic part which adapts itself to the estimation of
the evaluation of the root position returned by the search. In this patch,
we use x = 18 centipawns by default, and the y * eval correction can go
from -20 centipawns if the root eval is less than -2.0 pawns, up to +20
centipawns when the root eval is more than 2.0 pawns.

To summarize, the new contempt goes from -0.02 to 0.38 pawns, depending if
Stockfish is losing or winning, with an average value of 0.18 pawns by default.

LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 110052 W: 24614 L: 23938 D: 61500

LLR: 2.97 (-2.94,2.94) [0.00,5.00]
Total: 16470 W: 2896 L: 2705 D: 10869

A second match at LTC was organised against the current master:

ELO: 1.45 +-2.9 (95%) LOS: 84.0%
Total: 19369 W: 3350 L: 3269 D: 12750

Finally, we checked that there is no apparent problem with multithreading,
despite the fact that some threads might have a slightly different contempt
level that the main thread.

Match of this version against master, both using 5 threads, time control 30+0.3:
ELO: 2.18 +-3.2 (95%) LOS: 90.8%
Total: 14840 W: 2502 L: 2409 D: 9929

Include suggestions from Marco Costalba, Aram Tumanian, Ronald de Man, etc.

Bench: 5207156

descriptionStockfish 9 EmptyRe: Stockfish 9

by Alexei Chernakoff
New patch: Updated to "Simplify trapped rook"

descriptionStockfish 9 EmptyRe: Stockfish 9

Stockfish_240218 (pgo popcnt arm7, arm64v8) Android
Author: DU-jdto

Updated with the following patch:
Date: Sat Feb 24 13:12:04 2018 +0100
Timestamp: 1519474324

Simplification: do razoring only for depth 1

The razoring heuristic is quite a drastic pruning technique,
using a depth 0 search at internal nodes of the search tree
to estimate the true value of depth n nodes. This patch limits
this razoring to the case of internal nodes of depth 1.
Author: Jarrod Torriero (DU-jdto)

LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8043 W: 1865 L: 1716 D: 4462

LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 32890 W: 5577 L: 5476 D: 21837

Opportunities opened by this patch: it would be interesting to
know if it brings Elo to re-introduce razoring or soft razoring
at depth >= 2, maybe using a larger margin to compensate for the
increased pruning effect.

Bench: 5227124

descriptionStockfish 9 EmptyRe: Stockfish 9

Permissions in this forum:
You cannot reply to topics in this forum