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Stockfish Polyglot

description1972 - Stockfish Polyglot EmptyStockfish Polyglot

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https://chess.massimilianogoi.com/download/stockfish/

Massimiliano Goi wrote:

- Changelog: Tweak opposite colored bishops endgame scaling.

Due to the missing of this feature in the main release I have decided to create a Stockfish perfectly equal to the last beta version with the capability to use Polyglot books (aka .bin or BIN).


Version for 64bit, power pc, Haswell computers, 32bit and 32 bit old. For both Windows and Linux.

Last edited by jorge91 on Mon Apr 15, 2019 5:47 pm; edited 1 time in total

description1972 - Stockfish Polyglot EmptyRe: Stockfish Polyglot

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Stockfish Polyglot: Updated Ocber, 21 2018

- Changelog: This is the expansion of the Stockfish version having timestamp "1539542457":

"Simplify check extensions

Remove the !moveCountPruning condition for check extensions, which seems not necessary."

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 22238 W: 4835 L: 4715 D: 12688 Elo +1.87
http://tests.stockfishchess.org/tests/view/5bb3241a0ebc592439f6d2ac

LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 36593 W: 5898 L: 5802 D: 24893 Elo +0.91
http://tests.stockfishchess.org/tests/view/5bb34c220ebc592439f6d5dc

Bench: 4274207


Versions:

Windows:

- Stockfish_Polyglot_2018-10-21_32bit.exe
- Stockfish_Polyglot_2018-10-21_32bit_general.exe
- Stockfish_Polyglot_2018-10-21_32bit_old.exe
- Stockfish_Polyglot_2018-10-21_32bit_popc.exe
- Stockfish_Polyglot_2018-10-21_x64.exe
- Stockfish_Polyglot_2018-10-21_x64_bmi2.exe
- Stockfish_Polyglot_2018-10-21_x64_general.exe
- Stockfish_Polyglot_2018-10-21_x64_modern.exe
- Stockfish_Polyglot_2018-10-21_x64_popc.exe

Linux:

Stockfish_Polyglot_2018-10-21_32bit
Stockfish_Polyglot_2018-10-21_32bit_general
Stockfish_Polyglot_2018-10-21_32bit_old
Stockfish_Polyglot_2018-10-21_32bit_popc
Stockfish_Polyglot_2018-10-21_x64
Stockfish_Polyglot_2018-10-21_x64_bmi2
Stockfish_Polyglot_2018-10-21_x64_general
Stockfish_Polyglot_2018-10-21_x64_modern
Stockfish_Polyglot_2018-10-21_x64_popc

description1972 - Stockfish Polyglot EmptyRe: Stockfish Polyglot

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Stockfish Polyglot: Updated November, 11 2018

Massimiliano Goi wrote:
Intro: It was reported to me from Sedat Canbaz, then confirmed by other testers, that the previous version of Stockfish Polyglot made too few kylonodes per second...
I hope to have fixed this issue with this release, updated to the latest Stockfish beta. All I had to do to solve the issue was setting 'optimize = yes' in the source Makefile.



Stockfish Polyglot is none but the very own Stockfish with the only addition of the possibility to use Polyglot (.bin) books.
This distribution is enhanced by the pgo-build option.

Stockfish Polyglot comes with almost any architecture available, hence also for old 32bit operating systems like Windows XP, old machines, 64bit systems, standard machines, modern machines and power computers. It runs on both Windows and Linux. NOT FOR MACOS OR ANDROID.


- Changelog: This is the expansion of the Stockfish version having timestamp "1541192906":

Rook tweaks in evaluation

Some small changes in evaluation to try to convince Stockfish to centralize her rooks more in middle game and avoid trapping them in the corners. Joint work by SFisGOD and snicolet.

STC:
LLR: 2.96 (-2.94,2.94) [0.00,4.00]
Total: 99826 W: 21895 L: 21341 D: 56590 Elo +1.93
http://tests.stockfishchess.org/tests/view/5bdc3e280ebc595e0ae277df

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 21467 W: 3541 L: 3322 D: 14604 Elo +3.54
http://tests.stockfishchess.org/tests/view/5bdc9ff30ebc595e0ae28119

Bench: 3631608


Versions:

Windows:

- Stockfish_Polyglot_2018-11-04_32bit.exe
- Stockfish_Polyglot_2018-11-04_32bit_general.exe
- Stockfish_Polyglot_2018-11-04_32bit_old.exe
- Stockfish_Polyglot_2018-11-04_32bit_popc.exe
- Stockfish_Polyglot_2018-11-04_x64.exe
- Stockfish_Polyglot_2018-11-04_x64_bmi2.exe
- Stockfish_Polyglot_2018-11-04_x64_general.exe
- Stockfish_Polyglot_2018-11-04_x64_modern.exe
- Stockfish_Polyglot_2018-11-04_x64_popc.exe


Linux:

Stockfish_Polyglot_2018-11-04_32bit
Stockfish_Polyglot_2018-11-04_32bit_general
Stockfish_Polyglot_2018-11-04_32bit_old
Stockfish_Polyglot_2018-11-04_32bit_popc
Stockfish_Polyglot_2018-11-04_x64
Stockfish_Polyglot_2018-11-04_x64_bmi2
Stockfish_Polyglot_2018-11-04_x64_general
Stockfish_Polyglot_2018-11-04_x64_modern
Stockfish_Polyglot_2018-11-04_x64_popc

Last edited by jorge91 on Mon Nov 05, 2018 3:50 am; edited 3 times in total

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deleted for accidental double posting

Last edited by jorge91 on Mon Nov 05, 2018 3:42 am; edited 1 time in total (Reason for editing : deleted for accidental double posting)

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deleted for accidental double posting

Last edited by jorge91 on Mon Nov 05, 2018 3:51 am; edited 1 time in total (Reason for editing : deleted for accidental double posting)

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Stockfish Polyglot 2018-11-13

Massimiliano Goi wrote:


Since Stockfish Polyglot has made great results in the latest Playchess machines tournaments, even reaching the first place, I have decided to updated it to the latest Stockfish beta version.
This new release has alot of updates and elo raising.


Stockfish can reach up to 512 cores. From >8 cores it automatically enables the NUMA optimization, as far I have understood by reading the latest official Stockfish GitHub update.

Stockfish Polyglot is none but the very own Stockfish with the only addition of the possibility to use Polyglot (.bin) books. In order to do that I used the library polybook.h from Brainfish and merged with the Stockfish code. This new update features the 'OwnBook' checkbox as requested, so that you can easily switch from the Polyglot book to the local CTG book (Chessbase softwares) or ABK book (Arena GUI). I've wandered through GitHub to recover the 'OwnBook' checkbox code (it needed just two mere rows..), luckily I've managed to find it and extract the part I needed to use.

This distribution is enhanced by the pgo-build option.

Stockfish Polyglot comes with almost any architecture available, hence also for old 32bit operating systems like Windows XP, old machines, 64bit systems, standard machines, modern machines and power computers. It runs on both Windows and Linux. NOT FOR MACOS OR ANDROID, IF SOMEONE CAN COMPILE THIS SOFTWARE FOR THESE TWO SYSTEMS PLEASE WRITE ME CLICKING 'CONTACTS' ABOVE.

- Changelog: This is the expansion of the Stockfish version having timestamp "1542051187".

Versions:

Windows:

- Stockfish_Polyglot_2018-11-13_32bit.exe
- Stockfish_Polyglot_2018-11-13_32bit_general.exe
- Stockfish_Polyglot_2018-11-13_32bit_old.exe
- Stockfish_Polyglot_2018-11-13_32bit_popc.exe
- Stockfish_Polyglot_2018-11-13_x64.exe
- Stockfish_Polyglot_2018-11-13_x64_bmi2.exe
- Stockfish_Polyglot_2018-11-13_x64_general.exe
- Stockfish_Polyglot_2018-11-13_x64_modern.exe
- Stockfish_Polyglot_2018-11-13_x64_popc.exe


Linux:

Stockfish_Polyglot_2018-11-13_32bit
Stockfish_Polyglot_2018-11-13_32bit_general
Stockfish_Polyglot_2018-11-13_32bit_old
Stockfish_Polyglot_2018-11-13_32bit_popc
Stockfish_Polyglot_2018-11-13_x64
Stockfish_Polyglot_2018-11-13_x64_bmi2
Stockfish_Polyglot_2018-11-13_x64_general
Stockfish_Polyglot_2018-11-13_x64_modern
Stockfish_Polyglot_2018-11-13_x64_popc


Complete changelog:

- Changelog: This is the expansion of the Stockfish version having timestamp "1542051187".

From the previous version of Stockfish Polyglot the following changes/benchmarks were made by the official Stockfish team:

"Replace the PassedDanger array by an equation

This equation seems to do as well as the current PassedDanger array.

Master values were: 3, 7, 11, 20
The new values given by the equation are: 3, 6, 11, 18

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 84301 W: 18155 L: 18156 D: 47990 Elo -0.00
http://tests.stockfishchess.org/tests/view/5bda03180ebc595e0ae2518e

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 7940 W: 1358 L: 1217 D: 5365 Elo +6.17
http://tests.stockfishchess.org/tests/view/5bdc69880ebc595e0ae27d28

We stopped a LTC run after 70000 games:
LLR: 0.74 (-2.94,2.94) [0.00,4.00]
Total: 70257 W: 11319 L: 11064 D: 47874 Elo +1.26
http://tests.stockfishchess.org/tests/view/5bdca8420ebc595e0ae281a9

Bench: 3913185

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

Remove redundant king square parameter

We don't need to pass the king square as an explicit parameter to the functions
king_safety() and do_king_safety() since we already pass in the position.

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 69686 W: 14894 L: 14866 D: 39926 Elo +0.14
http://tests.stockfishchess.org/tests/view/5be84ac20ebc595e0ae3283c

No functional change.

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

Simplify tropism. (#1807)

We calculate tropism as a sum of two factors. The first is the number of squares in our kingFlank and Camp that are attacked by the enemy; the second is number of these squares that are attacked twice. Prior to this commit, we excluded squares we defended with pawns from this second value, but this appears unnecessary. (Doubly-attacked squares near our king are still dangerous.) The removal of this exclusion is a possible small Elo gain at STC (estimated +1.59) and almost exactly neutral at LTC (estimated +0.04).

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 20942 W: 4550 L: 4427 D: 11965 Elo +2.04
http://tests.stockfishchess.org/tests/view/5be4e0ae0ebc595e0ae308a0

LTC:
LLR: 2.94 (-2.94,2.94) [-3.00,1.00]
Total: 56941 W: 9172 L: 9108 D: 38661 Elo +0.39
http://tests.stockfishchess.org/tests/view/5be4ec340ebc595e0ae30938

Bench: 3813986

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

Pawn and Piece Values Tuned at LTC

Failed STC
LLR: -2.96 (-2.94,2.94) [0.00,4.00]
Total: 27487 W: 5846 L: 5903 D: 15738 Elo -0.72
http://tests.stockfishchess.org/tests/view/5be1d3190ebc595e0ae2e5b8

Passed 1st LTC
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 38503 W: 6270 L: 5999 D: 26234 Elo +2.45
http://tests.stockfishchess.org/tests/view/5be1f5ef0ebc595e0ae2e750

Passed 2nd LTC
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 34016 W: 5584 L: 5326 D: 23106 Elo +2.64
http://tests.stockfishchess.org/tests/view/5be2a1970ebc595e0ae2f1b4

This pull request lead to an interesting discussion about testing
methodology for Stockfish:
https://github.com/official-stockfish/Stockfish/pull/1804

Bench: 3647775

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

Extension for king moves changing castling rights

passed STC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 8463 W: 1919 L: 1747 D: 4797 Elo +7.06
http://tests.stockfishchess.org/tests/view/5be15d510ebc595e0ae2dec6

passed LTC:
LLR: 2.95 (-2.94,2.94) [0.00,5.00]
Total: 142590 W: 23263 L: 22587 D: 96740 Elo +1.65
http://tests.stockfishchess.org/tests/view/5be1667b0ebc595e0ae2df2d

Bench: 3607243

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

Simplify mobility danger

Check sign only after adding mobility danger term.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 9090 W: 2001 L: 1856 D: 5233 Elo +5.54
http://tests.stockfishchess.org/tests/view/5bdc5ee10ebc595e0ae27bc2

LTC
LLR: 2.94 (-2.94,2.94) [-3.00,1.00]
Total: 123466 W: 19766 L: 19805 D: 83895 Elo -0.11
http://tests.stockfishchess.org/tests/view/5bdc678e0ebc595e0ae27cf3

bench: 3630207

description1972 - Stockfish Polyglot Empty#12-3-2018: STOCKFISH POLYGLOT 10 HAS BEEN RELEASED.

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1972 - Stockfish Polyglot Stockfish_logo

Stockfish Polyglot 10:

Updated December, 3 2018

Intro: I knew since the very first moment that Stockfish 10 was released, and even before, because playing aroung with its betas I've seen a "Stockfish 10 beta", but I couldn't get my hands on it because I was fully busy on my Goi 5.1 CTG update 1 book day and night, that was a journey! Compared to that, the making of this compilation is ridiculous in terms of logistic. In the past Zagor Almanah's tournament I have seen great performances made by the previous version of Stockfish Polyglot, I'm expecting the same for this one. If you have any request, please feel free to write me in the Contacs Section.

Stockfish Polyglot is none but the very own Stockfish with the only addition of the possibility to use Polyglot (.bin) books. In order to do that I used the library polybook.h from Brainfish and merged with the Stockfish code. This new update features the 'OwnBook' checkbox as requested, so that you can easily switch from the Polyglot book to the local CTG book (Chessbase softwares) or ABK book (Arena GUI). I've wandered through GitHub to recover the 'OwnBook' checkbox code (it needed just two mere rows..), luckily I've managed to find it and extract the part I needed to use.

This distribution is enhanced by the pgo-build option.

Stockfish Polyglot comes with almost any architecture available, hence also for old 32bit operating systems like Windows XP, old machines, 64bit systems, standard machines, modern machines and power computers. It runs on both Windows and Linux. NOT YET FOR MACOS OR ANDROID.

Link: https://chess.massimilianogoi.com/download/stockfish/ .

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Stockfish Polyglot 181213

Massimiliano Goi wrote:

In this new beta version (NOT IN STOCKFISH 10!) the syntax has been changed, so I had to do something more than add the polybook Brainfish library: a very little adjustment on the syntax was needed, in particular castlingRights[Us] = pos.castling_rights(Us); has been changed with castlingRights[Us] = pos.can_castle(Us); in the file pawns.cpp and score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.castling_rights(Us)); has been changed with score -= (TrappedRook - make_score(mob * 22, 0)) * (1 + !pos.can_castle(Us)); in the file evaluate.cpp.

I've started experimenting by "transplanting" files from the Brainfish source to the original Stockfish... at the end it worked, but I felt it was too "Brainfish" instead of Stockfish... the bitboard.cpp file in the new Stockfish beta distribution is completely different... So I though to procede by keeping the original Stockfish files and examinating the compiler errors in search only for dependencies and I've ended up with these two changes above. That worked... don't ask me why, but it did.

Of course there are the routine changes in the following files:
- search.cpp
- main.cpp
- misc.cpp
- ucioption.cpp


so that Stockfish can read Polyglot (.bin) books; in no way the computation algorythms were changed, otherwise I would have created another engine and this is not the purpose of this project. I only want the most modern Stockfish reading bin books, period.

This latest update (not the Stockfish 10 one) is experimental, so downloading it you agree to handle with software that could not behave like you expect, since I precisely don't know how can affect the program the change of pos.castling_rights(Us) with pos.can_castle(Us), but I have tested it a few on the Playchess room and I have to say it was quite good. You can still download the original Stockfish Polyglot 10, though.

Binaries:

Windows:

- Stockfish_Polyglot_2018-12-13_32bit.exe
- Stockfish_Polyglot_2018-12-13_32bit_general.exe
- Stockfish_Polyglot_2018-12-13_32bit_old.exe
- Stockfish_Polyglot_2018-12-13_32bit_popc.exe
- Stockfish_Polyglot_2018-12-13_x64.exe
- Stockfish_Polyglot_2018-12-13_x64_bmi2.exe
- Stockfish_Polyglot_2018-12-13_x64_general.exe
- Stockfish_Polyglot_2018-12-13_x64_modern.exe
- Stockfish_Polyglot_2018-12-13_x64_popc.exe


Linux:

- Stockfish_Polyglot_2018-12-13_32bit
- Stockfish_Polyglot_2018-12-13_32bit_general
- Stockfish_Polyglot_2018-12-13_32bit_old
- Stockfish_Polyglot_2018-12-13_32bit_popc
- Stockfish_Polyglot_2018-12-13_x64
- Stockfish_Polyglot_2018-12-13_x64_bmi2
- Stockfish_Polyglot_2018-12-13_x64_general
- Stockfish_Polyglot_2018-12-13_x64_modern
- Stockfish_Polyglot_2018-12-13_x64_popc

description1972 - Stockfish Polyglot EmptyRe: Stockfish Polyglot

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Stockfish_Polyglot_2018-12-21

Massimiliano Goi wrote:

Something diabolical has happened to the code, and you'll realize it when you will see the size of the executables.
I guess now Stockfish has followed the binary optimization initially conceived for asmFish.



CHANGELOG:

This distribution is the expansion of Stockfish beta having timestamp: 1545299238 - Simplify KBNK endgame implementation.
Almost 10 ELO points stronger than the previous versions, according the official Stockfish tests.

Binaries of the latest version:

Windows:

- Stockfish_Polyglot_2018-12-21_32bit.exe
- Stockfish_Polyglot_2018-12-21_32bit_general.exe
- Stockfish_Polyglot_2018-12-21_32bit_old.exe
- Stockfish_Polyglot_2018-12-21_32bit_popc.exe
- Stockfish_Polyglot_2018-12-21_x64.exe
- Stockfish_Polyglot_2018-12-21_x64_bmi2.exe
- Stockfish_Polyglot_2018-12-21_x64_general.exe
- Stockfish_Polyglot_2018-12-21_x64_modern.exe
- Stockfish_Polyglot_2018-12-21_x64_popc.exe


Linux:

- Stockfish_Polyglot_2018-12-21_32bit
- Stockfish_Polyglot_2018-12-21_32bit_general
- Stockfish_Polyglot_2018-12-21_32bit_old
- Stockfish_Polyglot_2018-12-21_32bit_popc
- Stockfish_Polyglot_2018-12-21_x64
- Stockfish_Polyglot_2018-12-21_x64_bmi2
- Stockfish_Polyglot_2018-12-21_x64_general
- Stockfish_Polyglot_2018-12-21_x64_modern
- Stockfish_Polyglot_2018-12-21_x64_popc

MacOS:

- Stockfish_Polyglot_2018-12-21_x64
- Stockfish_Polyglot_2018-12-21_x64_bmi2
- Stockfish_Polyglot_2018-12-21_x64_modern

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Stockfish Polyglot 2019-01-06


New update, only for Windows now.

CHANGELOG:

This distribution is the expansion of Stockfish beta having timestamp: 1546612599 - Check tablebase files.
Complete changelog inside the zip archive.

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Stockfish Polyglot 2019-01-11 .

Massimiliano Goi wrote:
This is the second release of Stockfish Polyglot that includes the clustering function. I guess this means the program is optimized for machines having a large amount of threads.


CHANGELOG:

This distribution is the expansion of Stockfish beta having timestamp: 1547135164 - Remove pvExact.

The variable pvExact now overlaps with the pvHit concept. So you simplify the logic with small code tweaks to have pvHit trigger where pvExact previously triggered.

passed STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 20558 W: 4497 L: 4373 D: 11688 Elo +2.10
http://tests.stockfishchess.org/tests/view/5c36e9fd0ebc596a450c7885

passed LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 23482 W: 3888 L: 3772 D: 15822 Elo +1.72
http://tests.stockfishchess.org/tests/view/5c37072d0ebc596a450c7a52

Bench: 3739723


CHANGES FROM THE PREVIOUS STOCKFISH POLYGLOT VERSION:

Author: mstembera
Date: Thu Jan 10 16:36:59 2019 +0100
Timestamp: 1547134619

Minor cleanup to recent 'Flag critical search tree in hash table' patch

No functional change

Author: Joost VandeVondele
Date: Wed Jan 9 16:57:24 2019 +0100
Timestamp: 1547049444

Small improvements to the CI infrastructure

- avoid inlining for the debug testing so that suppressions work
- provide more output for triggered errors

No functional change.

Author: MJZ1977
Date: Wed Jan 9 15:05:33 2019 +0100
Timestamp: 1547042733

Flag critical search tree in hash table

Introducing new concept, saving principal lines into the transposition table to generate a "critical search tree" which we can reuse later for intelligent pruning/extension decisions.

For instance in this patch we just reduce reduction for these lines. But a lot of other ideas are possible.

To go further : tune some parameters, how to add or remove lines from the critical search tree, how to use these lines in search choices, etc.

STC :
LLR: 2.94 (-2.94,2.94) [0.50,4.50]
Total: 59761 W: 13321 L: 12863 D: 33577 Elo +2.66
http://tests.stockfishchess.org/tests/view/5c34da5d0ebc596a450c53d3

LTC :
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 26826 W: 4439 L: 4191 D: 18196 Elo +3.21
http://tests.stockfishchess.org/tests/view/5c35ceb00ebc596a450c65b2

Special thanks to Miguel Lahoz for his help in transposition table in/out.

Bench: 3399866

Author: Miguel Lahoz
Date: Sun Jan 6 16:02:31 2019 +0100
Timestamp: 1546786951

Introduce Multi-Cut

This was inspired after reading about [Multi-Cut](https://www.chessprogramming.org/Multi-Cut).

We now do non-singular cut node pruning. The idea is to prune when we have a "backup plan" in case our expected fail high node does not fail high on the ttMove.

For singular extensions, we do a search on all other moves but the ttMove. If this fails high on our original beta, this means that both the ttMove, as well as at least one other move was proven to fail high on a lower depth search. We then assume that one of these moves will work on a higher depth and prune.

STC:
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 72952 W: 16104 L: 15583 D: 41265 Elo +2.48
http://tests.stockfishchess.org/tests/view/5c3119640ebc596a450c0be5

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 27103 W: 4564 L: 4314 D: 18225 Elo +3.20
http://tests.stockfishchess.org/tests/view/5c3184c00ebc596a450c1662

Bench: 3145487


Binaries of the latest version:

Windows:

- Stockfish_Polyglot_2019-01-11_32bit.exe
- Stockfish_Polyglot_2019-01-11_32bit_general.exe
- Stockfish_Polyglot_2019-01-11_32bit_old.exe
- Stockfish_Polyglot_2019-01-11_32bit_popc.exe
- Stockfish_Polyglot_2019-01-11_x64.exe
- Stockfish_Polyglot_2019-01-11_x64_bmi2.exe
- Stockfish_Polyglot_2019-01-11_x64_general.exe
- Stockfish_Polyglot_2019-01-11_x64_modern.exe
- Stockfish_Polyglot_2019-01-11_x64_popc.exe


Linux:

- Stockfish_Polyglot_2019-01-11_32bit
- Stockfish_Polyglot_2019-01-11_32bit_general
- Stockfish_Polyglot_2019-01-11_32bit_old
- Stockfish_Polyglot_2019-01-11_32bit_popc
- Stockfish_Polyglot_2019-01-11_x64
- Stockfish_Polyglot_2019-01-11_x64_bmi2
- Stockfish_Polyglot_2019-01-11_x64_general
- Stockfish_Polyglot_2019-01-11_x64_modern
- Stockfish_Polyglot_2019-01-11_x64_popc

description1972 - Stockfish Polyglot EmptyRe: Stockfish Polyglot

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Stockfish Polyglot 2019-01-22 .

description1972 - Stockfish Polyglot EmptyRe: Stockfish Polyglot

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Stockfish Polyglot 30-01-19 .

CHANGELOG:

This distribution is the expansion of Stockfish beta having timestamp: 1548780000 - Don't update pvHit after IID.

CHANGES FROM THE PREVIOUS STOCKFISH POLYGLOT VERSION:

Author: DU-jdto
Date: Tue Jan 29 17:40:00 2019 +0100
Timestamp: 1548780000

Don't update pvHit after IID

This patch removes line 875 of search.cpp, which was updating pvHit after IID.
Bench testing at depth 22 shows that line 875 of search.cpp never changes the value of pvHit at NonPV nodes, while at PV nodes it often changes the value from true to false (and never the reverse). This is because the definition of pvHit at line 642 is :

pvHit = (ttHit && tte->pv_hit()) || (PvNode && depth > 4 * ONE_PLY);

while the assignment after IID omits the ` (PvNode && depth > 4 * ONE_PLY) ` condition. As such, unlike the other two post-IID tte reads, this line of code does not make SF's state more consistent, but rather introduces an inconsistency in the definition of pvHit. Indeed, changing line 875 read

pvHit = (ttHit && tte->pv_hit()) || (PvNode && depth > 4 * ONE_PLY);


to match line 642 is functionally equivalent to removing the line entirely, as this patch does.

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 62756 W: 13787 L: 13746 D: 35223 Elo +0.23

http://tests.stockfishchess.org/tests/view/5c446c850ebc5902bb5d4b75

LT
C LLR: 3.19 (-2.94,2.94) [-3.00,1.00]
Total: 61900 W: 10179 L: 10111 D: 41610 Elo +0.38

http://tests.stockfishchess.org/tests/view/5c45bf610ebc5902bb5d5d62

Bench: 3796134

Author: Miguel Lahoz
Date: Tue Jan 29 17:32:41 2019 +0100
Timestamp: 1548779561

Change pinning logic in Static Exchange Evaluation (SEE)

This changes 2 parts with regards to static exchange evaluation.

Currently, we do not allow pinned pieces to recapture if *all* opponent pinners are still in their starting squares. This changes that to having a less strict requirement, checking if *any* pinners are still in their starting square. This makes our SEE give more respect to the pinning side with regards to exchanges, which makes sense because it helps our search explore more tactical options.

Furthermore, we change the logic for saving pinners into our state variable when computing slider_blockers. We will include double pinners, where two sliders may be looking at the same blocker, a similar concept to our mobility calculation for sliders in our evaluation section. Interestingly, I think SEE is the only place where the pinners bitboard is actually used, so as far as I know there are no other side effects to this change.

An example and some insights:

White Bf2, Kg1
Black Qe3, Bc5

The move Qg3 will be given the correct value of 0. (Previously < 0)
The move Qd4 will be incorrectly given a value of 0. (Previously < 0)

It seems the tradeoff in search is worth it. Qd4 will likely be pruned soon by something like probcut anyway, while Qg3 could help us spot tactics at an earlier depth.

STC:
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 62162 W: 13879 L: 13408 D: 34875 Elo +2.63

http://tests.stockfishchess.org/tests/view/5c4ba1a70ebc593af5d49c55

LTC: (Thanks to @alayant)
LLR: 3.40 (-2.94,2.94) [0.00,3.50]
Total: 140285 W: 23416 L: 22825 D: 94044 Elo +1.46

http://tests.stockfishchess.org/tests/view/5c4ba1a70ebc593af5d49c55

Bench: 3937213

Author: Maciej Zenczykowski
Date: Tue Jan 29 17:26:24 2019 +0100
Timestamp: 1548779184

Use int8_t instead of int for SquareDistance[]

This patch saves (4-1) * 64 * 64 = 12KiB of cache.

STC
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 176120 W: 38944 L: 38087 D: 99089 Elo +1.69

http://tests.stockfishchess.org/tests/view/5c4c9f840ebc593af5d4a7ce

LTC
As a pure speed up, I've been informed it should not require LTC.

No functional change

Author: protonspring
Date: Tue Jan 22 09:54:10 2019 +0100
Timestamp: 1548147250

Simplify TrappedRook

Simplified TrappedRook to a single penalty removing the dependency on mobility.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 106718 W: 23530 L: 23577 D: 59611 Elo -0.15

http://tests.stockfishchess.org/tests/view/5c43f6bd0ebc5902bb5d4131

LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 54053 W: 8890 L: 8822 D: 36341 Elo +0.44

http://tests.stockfishchess.org/tests/view/5c44932a0ebc5902bb5d4d59

bench 3665090

Binaries:

Windows:

- Stockfish_Polyglot_2019-01-30_32bit.exe
- Stockfish_Polyglot_2019-01-30_32bit_general.exe
- Stockfish_Polyglot_2019-01-30_32bit_old.exe
- Stockfish_Polyglot_2019-01-30_32bit_popc.exe
- Stockfish_Polyglot_2019-01-30_x64.exe
- Stockfish_Polyglot_2019-01-30_x64_bmi2.exe
- Stockfish_Polyglot_2019-01-30_x64_general.exe
- Stockfish_Polyglot_2019-01-30_x64_modern.exe
- Stockfish_Polyglot_2019-01-30_x64_popc.exe


Linux:

- Stockfish_Polyglot_2019-01-30_32bit
- Stockfish_Polyglot_2019-01-30_32bit_general
- Stockfish_Polyglot_2019-01-30_32bit_old
- Stockfish_Polyglot_2019-01-30_32bit_popc
- Stockfish_Polyglot_2019-01-30_x64
- Stockfish_Polyglot_2019-01-30_x64_bmi2
- Stockfish_Polyglot_2019-01-30_x64_general
- Stockfish_Polyglot_2019-01-30_x64_modern
- Stockfish_Polyglot_2019-01-30_x64_popc


macOS (experimental, please write me if it doesn't work):

- Stockfish_Polyglot_2019-01-30_x64
- Stockfish_Polyglot_2019-01-30_x64_bmi2
- Stockfish_Polyglot_2019-01-30_x64_modern

description1972 - Stockfish Polyglot EmptyRe: Stockfish Polyglot

more_horiz
Stockfish Polyglot 2019-02-09 .

This distribution is the expansion of Stockfish beta having timestamp: 1549618288 - Change outposts to single value #1946.

Binaries:

Windows:

Stockfish_Polyglot_2019-02-09_32bit.exe
Stockfish_Polyglot_2019-02-09_32bit_general.exe
Stockfish_Polyglot_2019-02-09_32bit_old.exe
Stockfish_Polyglot_2019-02-09_32bit_popc.exe
Stockfish_Polyglot_2019-02-09_x64.exe
Stockfish_Polyglot_2019-02-09_x64_bmi2.exe
Stockfish_Polyglot_2019-02-09_x64_general.exe
Stockfish_Polyglot_2019-02-09_x64_modern.exe
Stockfish_Polyglot_2019-02-09_x64_popc.exe

Linux:

Stockfish_Polyglot_2019-02-09_32bit
Stockfish_Polyglot_2019-02-09_32bit_general
Stockfish_Polyglot_2019-02-09_32bit_old
Stockfish_Polyglot_2019-02-09_32bit_popc
Stockfish_Polyglot_2019-02-09_x64
Stockfish_Polyglot_2019-02-09_x64_bmi2
Stockfish_Polyglot_2019-02-09_x64_general
Stockfish_Polyglot_2019-02-09_x64_modern
Stockfish_Polyglot_2019-02-09_x64_popc

macOS (experimental, please write me if it doesn't work):

Stockfish_Polyglot_2019-02-09_x64
Stockfish_Polyglot_2019-02-09_x64_bmi2
Stockfish_Polyglot_2019-02-09_x64_general
Stockfish_Polyglot_2019-02-09_x64_modern


CHANGES FROM THE PREVIOUS STOCKFISH POLYGLOT VERSION:

Author: protonspring
Date: Fri Feb 8 10:31:28 2019 +0100
Timestamp: 1549618288

Change outposts to single value #1946

This is a functional simplification of the Outposts array moving it to a single value. This is a duplicate PR because I couldn't figure out how to fix the original one.

The idea is from @31m059 with formatting recommendations by @snicolet.

See #1940 for additional information.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 23933 W: 5279 L: 5162 D: 13492 Elo +1.70
http://tests.stockfishchess.org/tests/view/5c3575800ebc596a450c5ecb

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 41718 W: 6919 L: 6831 D: 27968 Elo +0.73
http://tests.stockfishchess.org/tests/view/5c358c440ebc596a450c6117

bench 3783543

Author: Marco Costalba
Date: Fri Feb 8 10:20:43 2019 +0100
Timestamp: 1549617643

Assorted trivial cleanups 1/2019

To address #1862

No functional change.

Author: Marco Costalba
Date: Fri Feb 8 10:19:00 2019 +0100
Timestamp: 1549617540

Log message of: Less king danger...

The commit:

Less king danger if we have a knight near by to defend it went in withouth proper commit message, here below we add it:

STC: LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 113106 W: 25087 L: 24367 D: 63652 Elo +2.21
http://tests.stockfishchess.org/tests/view/5c5517540ebc592fc7bb0eb4

LTC: LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 96669 W: 16318 L: 15872 D: 64479 Elo +1.60
http://tests.stockfishchess.org/tests/view/5c55352b0ebc592fc7bb11c8

bench: 3653942

Author: protonspring
Date: Fri Feb 8 09:54:38 2019 +0100
Timestamp: 1549616078

Remove Some Bitboard Arrays (#1963)

This is non-functional. These 5 arrays are simple enough to calculate real-time and maintaining an array for them does not help. Decreases the memory footprint.

This seems a tiny bit slower on my machine, but passed STC well enough. Could someone verify speed?

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 44745 W: 9780 L: 9704 D: 25261 Elo +0.59
http://tests.stockfishchess.org/tests/view/5c47aa2d0ebc5902bca13fc4

The slowdown is minimal even in 32 bit case (thanks to @mstembera for testing):

Compiled using make build ARCH=x86-32 CXX=i686-w64-mingw32-c++ and benched
This patch only:

```
Results for 40 tests for each version:

Base Test Diff
Mean 1455204 1450033 5171
StDev 49452 34533 59621

p-value: 0.465
speedup: -0.004
```

No functional change.

Author: mstembera
Date: Sun Feb 3 14:16:34 2019 +0100
Timestamp: 1549199794

Less king danger if we have a knight near by to defend it. (#1987)

bench: 3653942

Author: Miguel Lahoz
Date: Fri Feb 1 16:27:21 2019 +0100
Timestamp: 1549034841

Extend discovered checks regardless of SEE

A simple idea, but it makes sense: in current master the search is extended for checks that are considered somewhat safe, and for for this we use the static exchange evaluation which only considers the `to_sq` of a move. This is not reliable for discovered checks, where another piece is giving the check and is arguably a more dangerous type of check. Thus, if the check is a discovered check, the result of SEE is not relevant and can be ignored.

STC:
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 29370 W: 6583 L: 6274 D: 16513 Elo +3.66
http://tests.stockfishchess.org/tests/view/5c5062950ebc593af5d4d9b5

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 227341 W: 37972 L: 37165 D: 152204 Elo +1.23
http://tests.stockfishchess.org/tests/view/5c5094fb0ebc593af5d4dc2c

Bench: 3611854

Author: Stéphane Nicolet
Date: Fri Feb 1 15:34:46 2019 +0100
Timestamp: 1549031686

Tweak tropism weight in king danger

There was a simplification attempt last week for the tropism term in king danger, which passed STC but failed LTC. This was an indirect sign that maybe the tropism factor was sightly untuned in current master, so we tried to change it from 1/4 to 5/16.

STC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 28098 W: 6264 L: 5990 D: 15844 Elo +3.39
http://tests.stockfishchess.org/tests/view/5c518db60ebc593af5d4e306

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 103709 W: 17387 L: 16923 D: 69399 Elo +1.55
http://tests.stockfishchess.org/tests/view/5c52a5510ebc592fc7baea8b

Bench: 4016000

Author: Vizvezdenec
Date: Fri Feb 1 12:43:33 2019 +0100
Timestamp: 1549021413

More precise checks evaluation in king danger

Remove overlapping safe checks from kingdanger:
- rook and queen checks from the same square: rook check is preferred
- bishop and queen checks form the same square: queen check is preferred

Increase bishop and rook check values as a compensation.

STC
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 27480 W: 6111 L: 5813 D: 15556 Elo +3.77
http://tests.stockfishchess.org/tests/view/5c521d050ebc593af5d4e66a

LTC
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 78500 W: 13145 L: 12752 D: 52603 Elo +1.74
http://tests.stockfishchess.org/tests/view/5c52b9460ebc592fc7baecc5

Closes https://github.com/official-stockfish/Stockfish/pull/1983

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

I have quite a few ideas of how to improve this patch.

- actually rethinking it now it will maybe be useful to discount queen/bishop checks if there is only one square that they can give check from and it's "occupied" by more valuable check. Right now count of this squares does not really matter.

- maybe some small extra bonus can be given for overlapping checks.

- some ideas about using popcount() on safechecks can be retried.

- tune this safecheck values since they were more or less randomly handcrafted in this patch.

Bench: 3216489

Author: protonspring
Date: Thu Jan 31 15:21:24 2019 +0100
Timestamp: 1548944484

Simplify Stat Score bonus

This is a functional simplification of this statScore bonus.
There seems to be little risk of regression with this one.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 26829 W: 5892 L: 5781 D: 15156 Elo +1.44
http://tests.stockfishchess.org/tests/view/5c5086bb0ebc593af5d4db75

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 28232 W: 4684 L: 4575 D: 18973 Elo +1.34
http://tests.stockfishchess.org/tests/view/5c50d7690ebc593af5d4dec9

Closes https://github.com/official-stockfish/Stockfish/pull/1979

Bench: 4001014

description1972 - Stockfish Polyglot EmptyRe: Stockfish Polyglot

more_horiz
Stockfish Polyglot 2019-02-23 .

This distribution is the expansion of Stockfish beta having timestamp: 1549618288 - Add KNNvKP Endgame Heuristic.

Author: Kurtbusch
Date: Thu Feb 21 19:53:03 2019 +0100
Timestamp: 1550775183

Add KNNvKP Endgame Heuristic

This is a somewhat different patch. It fixes blindspots for two knights vs pawn endgame.

With local testing starting from random KNNvKP positions where the pawn has not advanced beyond the 4th rank (thanks @protonspring !) at 15+0.15 (4 cores), this went +105=868-27 against master. All except two losses were won in reverse.

The heuristic is simple but effective - the strategy in these endgames is to push the opposing king to the corner, then move the knight that's blocking the pawn in for the checkmate while the pawn is free to move and prevents stalemate. This patch gives SF the little boost it needs to search the relevant king-cornering mating lines.

See the discussion in pull request 1939 for some more good results for this test in independant tests:
https://github.com/official-stockfish/Stockfish/pull/1939%22

Bench: 3310239


Author: MJZ1977
Date: Thu Feb 21 19:36:48 2019 +0100
Timestamp: 1550774208

ProbCutCount limit dependancy to cutNode

Use the ProbCutCount limit `2 + 2 * cutNode` instead of constant 3.

STC
LLR: -2.95 (-2.94,2.94) [0.50,4.50]
Total: 61812 W: 13599 L: 13459 D: 34754 Elo +0.79
http://tests.stockfishchess.org/tests/view/5c6d19240ebc5925cffca07a%22

LTC LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 27549 W: 4614 L: 4363 D: 18572 Elo +3.17
http://tests.stockfishchess.org/tests/view/5c6d45c10ebc5925cffca7a6%22

Closes https://github.com/official-stockfish/Stockfish/pull/2015%22 .

Bench: 3368889

Author: protonspring
Date: Thu Feb 21 19:24:02 2019 +0100
Timestamp: 1550773442

Remove PvNode dimension from Reductions array

This is a functional simplification: if we simply subtract one to Reductions[]
when PvNode is set, we can remove this dimension of the multidimensional array.
I think this saves about 8K of memory.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 10118 W: 2282 L: 2138 D: 5698 Elo +4.95
http://tests.stockfishchess.org/tests/view/5c6332b60ebc5925cffbdfed%22

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 70765 W: 11617 L: 11575 D: 47573 Elo +0.21
http://tests.stockfishchess.org/tests/view/5c63379e0ebc5925cffbe0de%22

Closes https://github.com/official-stockfish/Stockfish/pull/2010%22 .

Bench 3261078

Author: protonspring
Date: Thu Feb 21 19:18:02 2019 +0100
Timestamp: 1550773082

Remove skipQuiets variable in search()

This is a functional simplification. The moveCountPruning variable and the skipQuiets variable are similar enough in function that they can be combined. This removes the skipQuiets variable in search.

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 23278 W: 5210 L: 5091 D: 12977 Elo +1.78
http://tests.stockfishchess.org/tests/view/5c65dc490ebc5925cffc12e9%22

LTC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 77107 W: 12792 L: 12761 D: 51554 Elo +0.14
http://tests.stockfishchess.org/tests/view/5c65e4360ebc5925cffc1490%22

Closes https://github.com/official-stockfish/Stockfish/pull/2011%22 .

bench 3640330


Binaries of the latest version:

Windows:

- Stockfish_Polyglot_2019-02-23_32bit.exe
- Stockfish_Polyglot_2019-02-23_32bit_general.exe
- Stockfish_Polyglot_2019-02-23_32bit_old.exe
- Stockfish_Polyglot_2019-02-23_32bit_popc.exe
- Stockfish_Polyglot_2019-02-23_x64.exe
- Stockfish_Polyglot_2019-02-23_x64_bmi2.exe
- Stockfish_Polyglot_2019-02-23_x64_general.exe
- Stockfish_Polyglot_2019-02-23_x64_modern.exe
- Stockfish_Polyglot_2019-02-23_x64_popc.exe


Linux:

- Stockfish_Polyglot_2019-02-23_32bit
- Stockfish_Polyglot_2019-02-23_32bit_general
- Stockfish_Polyglot_2019-02-23_32bit_old
- Stockfish_Polyglot_2019-02-23_32bit_popc
- Stockfish_Polyglot_2019-02-23_x64
- Stockfish_Polyglot_2019-02-23_x64_bmi2
- Stockfish_Polyglot_2019-02-23_x64_general
- Stockfish_Polyglot_2019-02-23_x64_modern
- Stockfish_Polyglot_2019-02-23_x64_popc

description1972 - Stockfish Polyglot EmptyRe: Stockfish Polyglot

more_horiz
Stockfish Polyglot: Updated March, 7 2019

- Matching official Stockfish beta having timestamp : 1549618288 - Add KNNvKP Endgame Heuristic. - ONLY FOR WINDOWS! NO LINUX, NO ANDROID, NO MACOS.

description1972 - Stockfish Polyglot EmptyRe: Stockfish Polyglot

more_horiz
Stockfish Polyglot: Updated March, 29 2019 .

Changelog:

This distribution is the expansion of Stockfish beta having timestamp: 1553445685 - Simplify pawn asymmetry (remove use of semiopen files). (#2054)

This is a functional simplification.

To me, the exclusive OR of semiopenFiles here is quite convoluted. Looks like it can be removed.

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 43885 W: 9731 L: 9653 D: 24501 Elo +0.62
http://tests.stockfishchess.org/tests/view/5c9041680ebc5925cfff10ea

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 68437 W: 11577 L: 11533 D: 45327 Elo +0.22
http://tests.stockfishchess.org/tests/view/5c9101740ebc5925cfff1cbf

bench 3575627

Author: Joost VandeVondele
Date: Sun Mar 24 17:40:29 2019 +0100
Timestamp: 1553445629

Remove unneeded condition. (#2057)

This is covered by the line just before. If we would like to protect
against the piece value of e.g. a N == B, this could be done by an
assert, no need to do this at runtime.

No functional change.

Author: protonspring
Date: Sun Mar 24 17:37:38 2019 +0100
Timestamp: 1553445458

Simplify Passed Pawns (#2058)

This is a non-functional simplification/speedup.

The truth-table for popcount(support) >= popcount(lever) - 1 is:
------------------lever
------------------0-------1---------2
support--0------X-------X---------0
-----------1------X-------X---------X
-----------2------X-------X---------X

Thus, it is functionally equivalent to just do: support || !more_than_one(lever) which removes the expensive popcounts and the -1.

Result of 20 runs:
base (...h_master.exe) = 1451680 +/- 8202
test (./stockfish ) = 1454781 +/- 8604
diff = +3101 +/- 931

STC
LLR: 2.94 (-2.94,2.94) [-3.00,1.00]
Total: 35424 W: 7768 L: 7674 D: 19982 Elo +0.92
Http://tests.stockfishchess.org/tests/view/5c970f170ebc5925cfff5e28

No functional change.

Author: xoto10
Date: Wed Mar 20 14:57:34 2019 +0100
Timestamp: 1553090254

Remove !extension check #2045

While looking at pruning using see_ge() (which is very valuable)
it became apparent that the !extension test is not adding any
value - simplify it away.

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 56843 W: 12621 L: 12569 D: 31653 Elo +0.32
http://tests.stockfishchess.org/tests/view/5c8588cb0ebc5925cffe77f4

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 78622 W: 13223 L: 13195 D: 52204 Elo +0.12
http://tests.stockfishchess.org/tests/view/5c8611cc0ebc5925cffe7f86

Further work could be to optimize the remaining see_ge() test. The idea of less pruning at higher depths is valuable, but perhaps the test (-PawnValueEg * depth) can be improved.

Bench: 3188688

Author: CoffeeOne
Date: Wed Mar 20 14:50:41 2019 +0100
Timestamp: 1553089841

Skip skipping thread scheme (#1972)


Several simplification tests (all with the bounds [-3,1]) were run:
5+0.05 8 threads, failed very quickly:
http://tests.stockfishchess.org/tests/view/5c439a020ebc5902bb5d3970

20+0.2 8 threads, also failed, but needed a lot more games:
http://tests.stockfishchess.org/tests/view/5c44b1b70ebc5902bb5d4e34

60+0.6 8 threads passed:
http://tests.stockfishchess.org/tests/view/5c48bfe40ebc5902bca15325

60+0.6 4 threads passed:
http://tests.stockfishchess.org/tests/view/5c4b71a00ebc593af5d49904

No functional change.

Author: Marco Costalba
Date: Tue Mar 12 08:35:10 2019 +0100
Timestamp: 1552376110

Increase thread stack for OS X (#2035)

On OS X threads other than the main thread are created with a reduced stack
size of 512KB by default, this is dangerously low for deep searches, so
adjust it to TH_STACK_SIZE. The implementation calls pthread_create() with
proper stack size parameter.

Verified for no regression at STC enabling the patch on all platforms where
pthread is supported.

LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 50873 W: 9768 L: 9700 D: 31405 Elo +0.46

No functional change.

Author: protonspring
Date: Sun Mar 10 10:53:39 2019 +0100
Timestamp: 1552211619

Remove popcount16() (#2038)

This is a non-functional simplification / code-style change.

This popcount16 method does nothing but initialize the PopCnt16 arrays.

This can be done in a single bitset line, which is less lines and more clear. Performance for this code is moot.

No functional change.

Author: xoto10
Date: Sun Mar 10 10:47:42 2019 +0100
Timestamp: 1552211262

Simplify failedLow away #1986

FailedLow doesn't seem to add any value so remove it.

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 43915 W: 9682 L: 9604 D: 24629 Elo +0.62
http://tests.stockfishchess.org/tests/view/5c5339770ebc592fc7baef74

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 58515 W: 9670 L: 9609 D: 39236 Elo +0.36
http://tests.stockfishchess.org/tests/view/5c53cc840ebc592fc7baf6c1

Ideas for further work:

Tune the values in the revised fallingEval calculation
Consider adding a term using delta, e.g. c * (delta - 20) as an indicator of eval instability

Bench: 3318033

Author: Marco Costalba
Date: Sat Mar 9 13:28:11 2019 +0100
Timestamp: 1552134491

Revert "Allowing singular extension in mate positions"

It was causing an assert: value > -VALUE_INFINITE
under some conditions.

See https://github.com/official-stockfish/Stockfish/issues/2036

Bench: 3318033

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Stockfish Polyglot: Updated Avril, 4 2019 .

This distribution is the expansion of Stockfish beta having timestamp: 1554025656 - Assorted trivial cleanups 3/2019 (#2030).

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Stockfish Polyglot: Updated Avril, 13 2019 .

This distribution is the expansion of Stockfish beta having timestamp: 1555069684 - Revert "Shuffle detection #2064".

Massimiliano Goi wrote:
The value max_threads = std::thread::hardware_concurrency(); has been added to ucioption.cpp so that the engine settings dialog box is set by default with the maximum number of threads.
This modification has been made by me being inspired by the Raubfisch default settings.

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Stockfish Polyglot: Updated Avril, 15 2019 and fixed .

This distribution is the expansion of Stockfish beta having timestamp: 1555069684 - Revert "Shuffle detection #2064".

- The bug on the UCI interface regarding the number of threads has been corrected (thanks to the user "engine ratings").
- The bug of the OwnBook checkbox not active has been corrected.


Changes since the last Stockfish Polyglot release:

Author: Joost VandeVondele
Date: Sat Apr 13 17:17:47 2019 +0200
Timestamp: 1555168667

Remove two useless assignments (#2093)

These variables are initialized before their use in the movepicker loop.

passed STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 138732 W: 30727 L: 30838 D: 77167 Elo -0.28
http://tests.stockfishchess.org/tests/view/5cb07af40ebc5925cf012c32

No functional change.

Author: Joost VandeVondele
Date: Sat Apr 13 17:15:15 2019 +0200
Timestamp: 1555168515

Give penalty for all early quiets of prev. ply

passed STC:
LLR: 2.94 (-2.94,2.94) [-3.00,1.00]
Total: 32884 W: 7283 L: 7184 D: 18417 Elo +1.05
http://tests.stockfishchess.org/tests/view/5cacb1b20ebc5925cf00ce97

passed LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 22869 W: 3920 L: 3803 D: 15146 Elo +1.78
http://tests.stockfishchess.org/tests/view/5cacbd760ebc5925cf00cfce

Bench: 3723099

Author: protonspring
Date: Sat Apr 13 16:58:41 2019 +0200
Timestamp: 1555167521

Simplify Connected Pawn Scoring #2090

This is a functional simplification that simplifies
connected scoring of pawns.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 37472 W: 8318 L: 8228 D: 20926 Elo +0.83
http://tests.stockfishchess.org/tests/view/5cae74ef0ebc5925cf00f8a5

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 43035 W: 7366 L: 7281 D: 28388 Elo +0.69
http://tests.stockfishchess.org/tests/view/5caea3b50ebc5925cf00fe1e

Bench: 3470173

Author: Massimiliano Goi
Date: Sat Apr 13 23:30:04 2019 +0200

The value max_threads = std::thread::hardware_concurrency(); has been added to ucioption.cpp so that the
engine settings dialog box is set by default with the maximum number of threads.

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Stockfish Polyglot: Updated Avril, 26 2019 .

This distribution is the expansion of Stockfish beta having timestamp: 1556128317 - Remove useless initializations (#2115)".

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Stockfish Polyglot: Updated May, 2 2019 .

This distribution is the expansion of Stockfish beta having timestamp: 1556390826 - Allow for address sanitizer. (#2119).

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Stockfish Polyglot: Updated May, 15 2019 .

This distribution is the expansion of Stockfish beta having timestamp: 1557912187 - Update failedHighCnt rule #2063..

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Stockfish Polyglot: Updated June, 4 2019 .

This distribution is the expansion of Stockfish beta having timestamp: 1559306139 - Scale lazy threshold according to material. (#2170).

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Stockfish Polyglot: Updated June, 21 2019 .

Changelog: This distribution is the expansion of Stockfish beta having timestamp 1561042322 - More bonus for free passed pawn.

WARNING: very consistent update with significant enhancement in quality of play. I suggest to anyone publishing tests with Stockfish Polyglot to repeat them with this latest version because of the substantial difference in Elo.

Binaries:

Stockfish_Polyglot_2019-06-21_32bit.exe
Stockfish_Polyglot_2019-06-21_32bit_general.exe
Stockfish_Polyglot_2019-06-21_32bit_old.exe
Stockfish_Polyglot_2019-06-21_32bit_popc.exe
Stockfish_Polyglot_2019-06-21_x64.exe
Stockfish_Polyglot_2019-06-21_x64_bmi2.exe
Stockfish_Polyglot_2019-06-21_x64_general.exe
Stockfish_Polyglot_2019-06-21_x64_modern.exe
Stockfish_Polyglot_2019-06-21_x64_popc.exe

Changes since the last Stockfish Polyglot release:

Author: Vizvezdenec
Date: Thu Jun 20 16:52:02 2019 +0200
Timestamp: 1561042322

More bonus for free passed pawn

Give even more bonus to passed pawn if adjacent squares to its path
are not attacked.

passed STC
http://tests.stockfishchess.org/tests/view/5d08c9b10ebc5925cf0a6630
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 175197 W: 39859 L: 38816 D: 96522 Elo +2.07

passed LTC
http://tests.stockfishchess.org/tests/view/5d0ab8240ebc5925cf0a8fe4
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 92928 W: 16124 L: 15682 D: 61122 Elo +1.65

Bench: 3398333

Author: Miguel Lahoz
Date: Thu Jun 20 16:39:22 2019 +0200
Timestamp: 1561041562

Change multi-cut pruning condition

Use comparison of eval with beta to predict potential cutNodes. This
allows multi-cut pruning to also prune possibly mislabeled Pv and NonPv
nodes.

STC:
LLR: 2.95 (-2.94,2.94) [0.50,4.50]
Total: 54305 W: 12302 L: 11867 D: 30136 Elo +2.78
http://tests.stockfishchess.org/tests/view/5d048ba50ebc5925cf0a15e8

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 189512 W: 32620 L: 31904 D: 124988 Elo +1.31
http://tests.stockfishchess.org/tests/view/5d04bf740ebc5925cf0a17f0

Normally I would think such changes are risky, specially for PvNodes,
but after trying a few other versions, it seems this version is more
sound than I initially thought.

Aside from this, a small funtional change is made to return
singularBeta instead of beta to be more consistent with the fail-soft
logic used in other parts of search.

=============================

How to continue from there ?

We could try to audit other parts of the search where the "cutNode"
variable is used, and try to use dynamic info based on heuristic
eval rather than on this variable, to check if the idea behind this
patch could also be applied successfuly.

Bench: 3503788

Author: VoyagerOne
Date: Thu Jun 20 16:22:45 2019 +0200
Timestamp: 1561040565

QuietPick Speed-up

Non-functional speedup: no need to generate, score, or sort quiet moves
if SkipQuiet is true. Thanks to @mstembera for his suggestion.

STC:
LLR: 2.95 (-2.94,2.94) [0.00,4.00]
Total: 27910 W: 6406 L: 6129 D: 15375 Elo +3.45
http://tests.stockfishchess.org/tests/view/5d07e0920ebc5925cf0a58a8

Closes https://github.com/official-stockfish/Stockfish/pull/2194

No functional change

Author: Joost VandeVondele
Date: Thu Jun 20 16:15:57 2019 +0200
Timestamp: 1561040157

Fix progress issue with shuffling extensions

Fixes issues #2126 and #2189 where no progress in rootDepth is made for particular fens:

8/8/3P3k/8/1p6/8/1P6/1K3n2 b - - 0 1
8/1r1rp1k1/1b1pPp2/2pP1Pp1/1pP3Pp/pP5P/P5K1/8 w - - 79 46

the cause are the shuffle extensions. Upon closer analysis, it appears that in these cases a shuffle extension is made for every node searched, and progess can not be made. This patch implements a fix, namely to limit the number of extensions relative to the number of nodes searched. The ratio employed is 1/4, which fixes the issues seen so far, but it is a heuristic, and I expect that certain positions might require an even smaller fraction.

The patch was tested as a bug fix and passed:

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 56601 W: 12633 L: 12581 D: 31387 Elo +0.32
http://tests.stockfishchess.org/tests/view/5d02b37a0ebc5925cf09f6da

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 52042 W: 8907 L: 8837 D: 34298 Elo +0.47
http://tests.stockfishchess.org/tests/view/5d0319420ebc5925cf09fe57

Furthermore, to confirm that the shuffle extension in this form indeed still brings Elo, one more test at VLTC was performed:
VLTC:
LLR: 2.96 (-2.94,2.94) [0.00,3.50]
Total: 142022 W: 20963 L: 20435 D: 100624 Elo +1.29
http://tests.stockfishchess.org/tests/view/5d03630d0ebc5925cf0a011a

Bench: 3961247

Author: syzygy1
Date: Thu Jun 20 16:09:40 2019 +0200
Timestamp: 1561039780

Partial revert of "Assorted trivial cleanups 5/2019".

Since root_probe() and root_probe_wdl() do not reset all tbRank values if they fail,
it is necessary to do this in rank_root_move(). This fixes issue #2196.
Alternatively, the loop could be moved into both root_probe() and root_probe_wdl().

No functional change

Author: VoyagerOne
Date: Fri Jun 14 19:59:17 2019 +0200
Timestamp: 1560535157

Simplify SEE Pruning (#2191)

Simplify SEE Pruning
Note this should also be a speedup...
If givesCheck is extended we know (except for DC) that it will have a positive SEE. So this new logic will be triggered before doing another expensive SEE function.

STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 24429 W: 5484 L: 5368 D: 13577 Elo +1.65
http://tests.stockfishchess.org/tests/view/5cffbccd0ebc5925cf09a154

LTC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 28428 W: 4873 L: 4765 D: 18790 Elo +1.32
http://tests.stockfishchess.org/tests/view/5d0015f60ebc5925cf09acb1

Bench: 3897263

Author: protonspring
Date: Fri Jun 14 08:22:02 2019 +0200
Timestamp: 1560493322

Remove backmost_sq (#2190)

This is a non-functional simplification.

backmost_sq and frontmost_sq are redundant. It seems quite clear to always use frontmost_sq and use the correct color.

Non functional change.

Author: Stefan Geschwentner
Date: Fri Jun 14 07:36:42 2019 +0200
Timestamp: 1560490602

Increase pawns cache (#2187)

Increase size of the pawns table by the factor 8. This decreases the number of recalculations of pawn structure information significantly (at least at LTC).

I have done measurements for different depths and pawn cache sizes.
First are given the number of pawn entry calculations are done (in parentheses is the frequency that a call to probe triggers a pawn entry calculation). The delta% are the percentage of less done pawn entry calculations in comparison to master

VSTC: bench 1 1 12
STC: bench 8 1 16
LTC: bench 64 1 20
VLTC: bench 512 1 24

VSTC STC LTC VLTC
master 82218(6%) 548935(6%) 2415422(7%) 9548071(7%)
pawncache*2 79859(6%) 492943(5%) 2084794(6%) 8275206(6%)
pawncache*4 78551(6%) 458758(5%) 1827770(5%) 7112531(5%)
pawncache*8 77963(6%) 439421(4%) 1649169(5%) 6128652(4%)

delta%(p2-m) -2.9% -10.2% -13.7% -13.3%
delta%(p4-m) -4.5% -16.4% -24.3% -25.5%
delta%(p8-m) -5.2% -20.0% -31.7% -35.8%

STC: (non-regression test because at STC the effect is smaller than at LTC)
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 22767 W: 5160 L: 5040 D: 12567 Elo +1.83
http://tests.stockfishchess.org/tests/view/5d00f6040ebc5925cf09c3e2

LTC:
LLR: 2.94 (-2.94,2.94) [0.00,4.00]
Total: 26340 W: 4524 L: 4286 D: 17530 Elo +3.14
http://tests.stockfishchess.org/tests/view/5d00a3810ebc5925cf09ba16

No functional change.

Author: VoyagerOne
Date: Mon Jun 10 00:26:47 2019 +0200
Timestamp: 1560119207

No DC prune in QS (#2185)

Don't prune discover checks in qSearch

STC:
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 23176 W: 5320 L: 5039 D: 12817 Elo +4.21
http://tests.stockfishchess.org/tests/view/5cfbc9350ebc5925cf094ab3

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 128428 W: 22222 L: 21679 D: 84527 Elo +1.47
http://tests.stockfishchess.org/tests/view/5cfbf0b70ebc5925cf094ebc

Bench: 3883245

Author: Marco Costalba
Date: Sun Jun 9 14:57:08 2019 +0200
Timestamp: 1560085028

Assorted trivial cleanups 5/2019

No functional change.

bench: 4178282

Author: Stefan Geschwentner
Date: Sun Jun 9 14:34:51 2019 +0200
Timestamp: 1560083691

Remove depth condition for ttPv (#2166)

Currently PV nodes with a depth <= 4 were ignored for ttPv. Now remove this constraint and use all PV nodes.

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 52209 W: 11755 L: 11694 D: 28760 Elo +0.41
http://tests.stockfishchess.org/tests/view/5cebc2d30ebc5925cf07b93a

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 20874 W: 3689 L: 3568 D: 13617 Elo +2.01
http://tests.stockfishchess.org/tests/view/5cec01fc0ebc5925cf07c62d

Author: protonspring
Date: Sun Jun 9 14:33:34 2019 +0200
Timestamp: 1560083614

Simplify passed pawns. (#2159)

This is a functional simplification.

If all of the stoppers are levers, a simple pawn push passes.

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 41768 W: 9360 L: 9278 D: 23130 Elo +0.68
http://tests.stockfishchess.org/tests/view/5ce82ed60ebc5925cf073a79

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 40463 W: 6964 L: 6875 D: 26624 Elo +0.76
http://tests.stockfishchess.org/tests/view/5ce87d0b0ebc5925cf07472b

Author: protonspring
Date: Sun Jun 9 14:31:16 2019 +0200
Timestamp: 1560083476

Remove a few file_of's (simplify adjacent_files_bb) #2171

This is a non-functional simplification that removes two file_of(s).

STC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 22030 W: 5106 L: 4984 D: 11940 Elo +1.92
http://tests.stockfishchess.org/tests/view/5cf028de0ebc5925cf0839e7

Author: protonspring
Date: Sun Jun 9 14:28:42 2019 +0200
Timestamp: 1560083322

Simplify WeakUnopposedPawn #2181

This is a functional simplification.

Moves WeakUnopposedPawn to pawns.cpp and remove piece dependency.

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 8699 W: 2000 L: 1853 D: 4846 Elo +5.87
http://tests.stockfishchess.org/tests/view/5cf7721b0ebc5925cf08ee79

LTC
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 46605 W: 7969 L: 7890 D: 30746 Elo +0.59
http://tests.stockfishchess.org/tests/view/5cf7d5f70ebc5925cf08fa96

Author: VoyagerOne
Date: Sun Jun 9 14:27:50 2019 +0200
Timestamp: 1560083270

SEE Pruning Tweak (#2183)

Don't SEE prune any check extensions

STC (yellow):
LLR: -2.96 (-2.94,2.94) [0.50,4.50]
Total: 129934 W: 29390 L: 28905 D: 71639 Elo +1.30
http://tests.stockfishchess.org/tests/view/5cf6b1a70ebc5925cf08dedb

LTC:
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 102115 W: 17692 L: 17224 D: 67199 Elo +1.59
http://tests.stockfishchess.org/tests/view/5cf830710ebc5925cf090331

Author: Michael Chaly
Date: Sun Jun 9 14:26:53 2019 +0200
Timestamp: 1560083213

Advanced pawn pushes tweak (#2175)

passed STC
http://tests.stockfishchess.org/tests/view/5cf586ee0ebc5925cf08c0ed
LLR: 2.96 (-2.94,2.94) [0.50,4.50]
Total: 29496 W: 6718 L: 6406 D: 16372 Elo +3.68

passed LTC
http://tests.stockfishchess.org/tests/view/5cf59b630ebc5925cf08c343
LLR: 2.95 (-2.94,2.94) [0.00,3.50]
Total: 40778 W: 7057 L: 6765 D: 26956 Elo +2.49

original idea from early 2018 by @jerrydonaldwatson
Code slightly rewritten to be shorter and more logical, no functinal changes
compared to passed patch.

Author: protonspring
Date: Sun Jun 9 14:24:06 2019 +0200
Timestamp: 1560083046

Simplify Outposts #2176

This is a functional simplification. This is NOT the exact version that was tested. Beyond the testing, an assignment was removed and a piece changes for consistency.

Instead of rewarding ANY square past an opponent pawn as an "outpost," only use squares that are protected by our pawn. I believe this is more consistent with what the chess world calls an "outpost."

STC
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 23540 W: 5387 L: 5269 D: 12884 Elo +1.74
http://tests.stockfishchess.org/tests/view/5cf51e6d0ebc5925cf08b823

LTC
LLR: 2.94 (-2.94,2.94) [-3.00,1.00]
Total: 53085 W: 9271 L: 9204 D: 34610 Elo +0.44
http://tests.stockfishchess.org/tests/view/5cf5279e0ebc5925cf08b992

bench 3424592

Author: 31m059
Date: Sun Jun 9 14:19:07 2019 +0200
Timestamp: 1560082747

Simplify k-value for passers. Bench: 3854907 (#2182)

Stockfish evaluates passed pawns in part based on a variable k, which shapes the passed pawn bonus based on the number of squares between the current square and promotion square that are attacked by enemy pieces, and the number defended by friendly ones. Prior to this commit, we gave a large bonus when all squares between the pawn and the promotion square were defended, and if they were not, a somewhat smaller bonus if at least the pawn's next square was. However, this distinction does not appear to provide any Elo at STC or LTC.

Where do we go from here? Many promising Elo-gaining patches were attempted in the past few months to refine passed pawn calculation, by altering the definitions of unsafe and defended squares. Stockfish uses these definitions to choose the value of k, so those tests interact with this PR. Therefore, it may be worthwhile to retest previously promising but not-quite-passing tests in the vicinity of this patch.

STC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 42344 W: 9455 L: 9374 D: 23515 Elo +0.66
http://tests.stockfishchess.org/tests/view/5cf83ede0ebc5925cf0904fb

LTC:
LLR: 2.96 (-2.94,2.94) [-3.00,1.00]
Total: 69548 W: 11855 L: 11813 D: 45880 Elo +0.21
http://tests.stockfishchess.org/tests/view/5cf8698f0ebc5925cf0908c8

Bench: 3854907

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