Michael Chaly and Joost VandeVondele
44b1ba89a9
Adjust pruning constants
...
This patch is a modification of original tuning done by vondele that failed yellow.
Value differences are divided by 2.
Passed STC
https://tests.stockfishchess.org/tests/view/61d918239fea7913d9c64cdf
LLR: 2.94 (-2.94,2.94) <0.00,2.50>
Total: 98968 W: 26248 L: 25858 D: 46862
Ptnml(0-2): 392, 11085, 26156, 11443, 408
Passed LTC
https://tests.stockfishchess.org/tests/view/61d99e3c9fea7913d9c663e4
LLR: 2.95 (-2.94,2.94) <0.50,3.00>
Total: 215232 W: 58191 L: 57492 D: 99549
Ptnml(0-2): 271, 22124, 62138, 22801, 282
closes https://github.com/official-stockfish/Stockfish/pull/3885
bench 4572746
2022-01-10 19:35:53 +01:00
Brad Knox and Joost VandeVondele
ad926d34c0
Update copyright years
...
Happy New Year!
closes https://github.com/official-stockfish/Stockfish/pull/3881
No functional change
2022-01-06 15:45:45 +01:00
lonfom169 and Stéphane Nicolet
0b41887527
Simplify away rangeReduction
...
Remove rangeReduction, introduced in [#3717 ](https://github.com/official-stockfish/Stockfish/pull/3717 ),
as it seemingly doesn't bring enough ELO anymore. It might be interesting to add
new forms of reduction or tune the reduction formula in the future.
STC:
LLR: 2.95 (-2.94,2.94) <-2.25,0.25>
Total: 45008 W: 12114 L: 11972 D: 20922
Ptnml(0-2): 174, 5031, 11952, 5173, 174
https://tests.stockfishchess.org/tests/view/61d08b7b069ca917749c9f6f
LTC:
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 30792 W: 8235 L: 8086 D: 14471
Ptnml(0-2): 24, 3162, 8882, 3297, 31
https://tests.stockfishchess.org/tests/view/61d0a6ad069ca917749ca420
closes https://github.com/official-stockfish/Stockfish/pull/3878
Bench: 4048312
2022-01-02 17:49:44 +01:00
lonfom169 and Stéphane Nicolet
061f98a9e3
Smooth out doDeeperSearch
...
Adjust threshold based on the difference between newDepth and LMR depth.
With more reduction, bigger fail-high is required in order to perform the deeper search.
STC:
LLR: 2.96 (-2.94,2.94) <0.00,2.50>
Total: 93576 W: 24133 L: 23758 D: 45685
Ptnml(0-2): 260, 10493, 24935, 10812, 288
https://tests.stockfishchess.org/tests/view/61cbb5cee68b2a714b6eaf09
LTC:
LLR: 2.94 (-2.94,2.94) <0.50,3.00>
Total: 109280 W: 28198 L: 27754 D: 53328
Ptnml(0-2): 60, 11225, 31637, 11647, 71
https://tests.stockfishchess.org/tests/view/61cc03fee68b2a714b6ec091
closes https://github.com/official-stockfish/Stockfish/pull/3877
Bench: 4464723
2021-12-31 07:44:15 +01:00
bmc4 and Joost VandeVondele
93b14a17d1
Don't direct prune a move if it's a retake
...
STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.50>
Total: 36304 W: 9499 L: 9226 D: 17579
Ptnml(0-2): 96, 4102, 9508, 4325, 121
https://tests.stockfishchess.org/tests/view/61c7069ae68b2a714b6dca27
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.00>
Total: 93824 W: 24478 L: 24068 D: 45278
Ptnml(0-2): 70, 9644, 27082, 10038, 78
https://tests.stockfishchess.org/tests/view/61c725fee68b2a714b6dcfa2
closes https://github.com/official-stockfish/Stockfish/pull/3871
Bench: 4106806
2021-12-27 16:43:44 +01:00
bmc4 and Joost VandeVondele
88f17a814d
Update Elo estimates for terms in search
...
This updates estimates from 2yr ago #2401 , and adds missing terms.
All tests run at 10+0.1 (STC), 20000 games, error bars +- 1.8 Elo, book 8moves_v3.png.
A table of Elo values with the links to the corresponding tests can be found at the PR
closes https://github.com/official-stockfish/Stockfish/pull/3868
Non-functional Change
2021-12-21 13:47:57 +01:00
bmc4 and Joost VandeVondele
22e92d23d2
Remove Capture history pruning
...
Fixed number of games. (book: 8moves_v3.png):
ELO: -0.69 +-1.8 (95%) LOS: 22.1%
Total: 20000 W: 1592 L: 1632 D: 16776
Ptnml(0-2): 44, 1194, 7566, 1150, 46
https://tests.stockfishchess.org/tests/view/61bb8eb657a0d0f327c30ce8
STC:
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 139976 W: 36039 L: 36036 D: 67901
Ptnml(0-2): 435, 16138, 36885, 16049, 481
https://tests.stockfishchess.org/tests/view/61be731857a0d0f327c39ea2
LTC:
LLR: 2.95 (-2.94,2.94) <-2.25,0.25>
Total: 70656 W: 18284 L: 18189 D: 34183
Ptnml(0-2): 34, 7317, 20529, 7416, 32
https://tests.stockfishchess.org/tests/view/61bf39b657a0d0f327c3c37b
closes https://github.com/official-stockfish/Stockfish/pull/3867
bench: 4281737
2021-12-21 13:42:33 +01:00
bmc4 and Joost VandeVondele
2c30956a13
Remove Capture Extension
...
This revert the patch #3692 , probably can be simplified after the introduction of #3838 .
Fixed-game test:
ELO: -1.41 +-1.8 (95%) LOS: 5.9%
Total: 20000 W: 1552 L: 1633 D: 16815
Ptnml(0-2): 38, 1242, 7517, 1169, 34
https://tests.stockfishchess.org/tests/view/61bc1a2057a0d0f327c32a3c
STC:
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 44528 W: 11619 L: 11478 D: 21431
Ptnml(0-2): 146, 5020, 11771, 5201, 126
https://tests.stockfishchess.org/tests/view/61bc638c57a0d0f327c338fe
LTC:
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 34136 W: 8847 L: 8704 D: 16585
Ptnml(0-2): 23, 3475, 9925, 3626, 19
https://tests.stockfishchess.org/tests/view/61bcb24257a0d0f327c34813
closes https://github.com/official-stockfish/Stockfish/pull/3863
Bench: 4054695
2021-12-21 13:40:57 +01:00
Michael Chaly and Joost VandeVondele
fb7d3ab32e
Reintroduce futility pruning for captures
...
This is a reintroduction of an idea that was simplified away approximately 1 year ago.
There are some tweaks to it :
a) exclude promotions;
b) exclude Pv Nodes from it - Pv Nodes logic for captures is really different from non Pv nodes so it makes a lot of sense;
c) use a big grain of capture history - idea is taken from my recent patches in futility pruning.
passed STC
https://tests.stockfishchess.org/tests/view/61bd90f857a0d0f327c373b7
LLR: 2.96 (-2.94,2.94) <0.00,2.50>
Total: 86640 W: 22474 L: 22110 D: 42056
Ptnml(0-2): 268, 9732, 22963, 10082, 275
passed LTC
https://tests.stockfishchess.org/tests/view/61be094457a0d0f327c38aa3
LLR: 2.95 (-2.94,2.94) <0.50,3.00>
Total: 23240 W: 6079 L: 5838 D: 11323
Ptnml(0-2): 14, 2261, 6824, 2512, 9
https://github.com/official-stockfish/Stockfish/pull/3864
bench 4493723
2021-12-19 08:03:41 +01:00
Michael Chaly and Joost VandeVondele
0a318cdddf
Adjust reductions based on current node delta and root delta
...
This patch is a follow up of previous 2 patches that introduced more reductions for PV nodes with low delta and more pruning for nodes with low delta. Instead of writing separate heuristics now it adjust reductions based on delta / rootDelta - it allows to remove 3 separate adjustements of pruning/LMR in different places and also makes reduction dependence on delta and rootDelta smoother. Also now it works for all pruning heuristics and not just 2.
Passed STC
https://tests.stockfishchess.org/tests/view/61ba9b6c57a0d0f327c2d48b
LLR: 2.94 (-2.94,2.94) <0.00,2.50>
Total: 79192 W: 20513 L: 20163 D: 38516
Ptnml(0-2): 238, 8900, 21024, 9142, 292
passed LTC
https://tests.stockfishchess.org/tests/view/61baf77557a0d0f327c2eb8e
LLR: 2.96 (-2.94,2.94) <0.50,3.00>
Total: 158400 W: 41134 L: 40572 D: 76694
Ptnml(0-2): 101, 16372, 45745, 16828, 154
closes https://github.com/official-stockfish/Stockfish/pull/3862
bench 4651538
2021-12-18 17:19:21 +01:00
pb00067 and Stéphane Nicolet
dc5d9bdfee
Remove lowPly history
...
Seems that after pull request #3731 (Capping stat bonus at 2000) this
heuristic is no longer useful.
STC:
https://tests.stockfishchess.org/tests/view/61b8d0e2dffbe89a35815444
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 30672 W: 7974 L: 7812 D: 14886
Ptnml(0-2): 106, 3436, 8072, 3634, 88
LTC:
https://tests.stockfishchess.org/tests/view/61b8e90cdffbe89a35815a67
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 42448 W: 10884 L: 10751 D: 20813
Ptnml(0-2): 23, 4394, 12267, 4507, 33
closes https://github.com/official-stockfish/Stockfish/pull/3853
bench: 4474950
2021-12-17 18:37:41 +01:00
bmc4 and Stéphane Nicolet
0889210262
Simplify away singularQuietLMR
...
While at it, we also update the Elo estimate of reduction at non-PV nodes
(source: https://tests.stockfishchess.org/tests/view/61acf97156fcf33bce7d6303 )
STC:
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 243632 W: 62874 L: 63022 D: 117736
Ptnml(0-2): 810, 28024, 64249, 27970, 763
https://tests.stockfishchess.org/tests/view/61b8b1b7dffbe89a35814c0d
LTC:
LLR: 2.93 (-2.94,2.94) <-2.25,0.25>
Total: 91392 W: 23520 L: 23453 D: 44419
Ptnml(0-2): 51, 9568, 26387, 9643, 47
https://tests.stockfishchess.org/tests/view/61b97316dffbe89a35817da7
closes https://github.com/official-stockfish/Stockfish/pull/3854
bench: 4217785
2021-12-17 18:22:48 +01:00
Stefan Geschwentner and Joost VandeVondele
d579db34a3
Simplify falling eval time factor.
...
Remove the difference to previous best score in falling eval calculation. As compensation double the effect of the difference to previous best average score.
STC:
LLR: 2.95 (-2.94,2.94) <-2.25,0.25>
Total: 86944 W: 22363 L: 22285 D: 42296
Ptnml(0-2): 273, 9227, 24396, 9301, 275
https://tests.stockfishchess.org/tests/view/61b111ce06b4c2dcb1b11546
LTC:
LLR: 2.96 (-2.94,2.94) <-2.25,0.25>
Total: 134944 W: 34606 L: 34596 D: 65742
Ptnml(0-2): 66, 12941, 41456, 12935, 74
https://tests.stockfishchess.org/tests/view/61b19ca206b4c2dcb1b13a8b
closes https://github.com/official-stockfish/Stockfish/pull/3841
Bench: 4729473
2021-12-11 15:56:38 +01:00
Michael Chaly and Joost VandeVondele
8e82345931
Adjust singular extension depth restriction
...
This patch is a modification of original idea by lonfom169 which had a good yellow run
- do singular extension search with depth threshold 6 unless this is a PvNode with is a part of a PV line -
for them set threshold to 8 instead.
Passed STC
https://tests.stockfishchess.org/tests/view/61b1080406b4c2dcb1b1128c
LLR: 2.95 (-2.94,2.94) <0.00,2.50>
Total: 84352 W: 21917 L: 21555 D: 40880
Ptnml(0-2): 288, 9524, 22185, 9896, 283
Passed LTC
https://tests.stockfishchess.org/tests/view/61b1860a06b4c2dcb1b134a1
LLR: 2.95 (-2.94,2.94) <0.50,3.00>
Total: 63520 W: 16575 L: 16237 D: 30708
Ptnml(0-2): 27, 6519, 18350, 6817, 47
https://github.com/official-stockfish/Stockfish/pull/3840
bench 4729473
2021-12-09 20:50:00 +01:00
Michael Chaly and Joost VandeVondele
c228f3196a
Introduce post-lmr extensions
...
This idea is somewhat similar to extentions in LMR but has a different flavour.
If result of LMR was really good - thus exceeded alpha by some pretty
big given margin, we can extend move after LMR in full depth search with 0 window.
The idea is that this move is probably a fail high with somewhat of a big
probability so extending it makes a lot of sense
passed STC
https://tests.stockfishchess.org/tests/view/61ad45ea56fcf33bce7d74b7
LLR: 2.94 (-2.94,2.94) <0.00,2.50>
Total: 59680 W: 15531 L: 15215 D: 28934
Ptnml(0-2): 193, 6711, 15734, 6991, 211
passed LTC
https://tests.stockfishchess.org/tests/view/61ad9ff356fcf33bce7d8646
LLR: 2.95 (-2.94,2.94) <0.50,3.00>
Total: 59104 W: 15321 L: 14992 D: 28791
Ptnml(0-2): 53, 6023, 17065, 6364, 47
closes https://github.com/official-stockfish/Stockfish/pull/3838
bench 4881329
2021-12-07 18:15:06 +01:00
Michael Chaly and Joost VandeVondele
a3d425cf55
Assign extra bonus for previous move that caused a fail low more often
...
This patch allows to assign extra bonus for previous move that caused a fail low not only for PvNodes and cutNodes but also fo some allNodes - namely if the best result we could've got from the search is still far below alpha.
passed STC
https://tests.stockfishchess.org/tests/view/61aa26a49e8855bba1a36d96
LLR: 2.94 (-2.94,2.94) <0.00,2.50>
Total: 73808 W: 19183 L: 18842 D: 35783
Ptnml(0-2): 251, 8257, 19564, 8564, 268
passed LTC
https://tests.stockfishchess.org/tests/view/61aa7dc29e8855bba1a3814f
LLR: 2.94 (-2.94,2.94) <0.50,3.00>
Total: 142416 W: 36717 L: 36192 D: 69507
Ptnml(0-2): 106, 14799, 40862, 15346, 95
closes https://github.com/official-stockfish/Stockfish/pull/3835
bench 4724181
2021-12-06 07:42:04 +01:00
Stefan Geschwentner and Stéphane Nicolet
18f2b12cd0
Tweak time management
...
Use for adjustment of the falling eval time factor now also the difference
between previous best average score and current best score.
STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.50>
Total: 109216 W: 28296 L: 27900 D: 53020
Ptnml(0-2): 312, 11759, 30148, 11999, 390
https://tests.stockfishchess.org/tests/view/61aafa8d1b31b85bcfa29d9c
LTC:
LLR: 2.93 (-2.94,2.94) <0.50,3.00>
Total: 54096 W: 14091 L: 13787 D: 26218
Ptnml(0-2): 29, 5124, 16447, 5410, 38
https://tests.stockfishchess.org/tests/view/61abbbbd56fcf33bce7d1d64
closes https://github.com/official-stockfish/Stockfish/pull/3833
Bench: 4829419
2021-12-05 17:56:54 +01:00
bmc4 and Stéphane Nicolet
a6a9d828ab
Simplifies bestMoveChanges from LMR
...
As bestMoveChanges is only reset on mainThread and it could change how other
threads search, a multi-threads test was made.
STC:
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 146776 W: 37934 L: 37941 D: 70901
Ptnml(0-2): 477, 15644, 41173, 15597, 497
https://tests.stockfishchess.org/tests/view/61a8f9f34ed77d629d4ea2d6
LTC:
LLR: 3.11 (-2.94,2.94) <-2.25,0.25>
Total: 114040 W: 29314 L: 29269 D: 55457
Ptnml(0-2): 50, 10584, 35722, 10599, 65
https://tests.stockfishchess.org/tests/view/61a9d4bf9e8855bba1a35c4f
(SMP, 8 threads) STC:
LLR: 2.95 (-2.94,2.94) <-2.25,0.25>
Total: 23888 W: 6308 L: 6143 D: 11437
Ptnml(0-2): 36, 2557, 6600, 2708, 43
https://tests.stockfishchess.org/tests/view/61ac27a756fcf33bce7d3677
closes https://github.com/official-stockfish/Stockfish/pull/3831
bench: 4829419
2021-12-05 17:50:04 +01:00
Michael Chaly and Joost VandeVondele
e4b7403f12
Do more aggressive pruning for some node types
...
This patch allows more aggressive futility/see based pruning for PV nodes with low delta and non-pv nodes.
Fixes some white space issues.
Passed STC
https://tests.stockfishchess.org/tests/view/61a5ed33d16c530b5dcc27cc
LLR: 2.95 (-2.94,2.94) <0.00,2.50>
Total: 182088 W: 47121 L: 46584 D: 88383
Ptnml(0-2): 551, 20687, 48037, 21212, 557
Passed LTC
https://tests.stockfishchess.org/tests/view/61a74dfdbd5c4360bcded0ac
LLR: 2.94 (-2.94,2.94) <0.50,3.00>
Total: 87136 W: 22494 L: 22103 D: 42539
Ptnml(0-2): 38, 8918, 25272, 9295, 45
closes https://github.com/official-stockfish/Stockfish/pull/3828
closes https://github.com/official-stockfish/Stockfish/pull/3829
bench 4332259
2021-12-03 08:54:46 +01:00
bmc4 and Joost VandeVondele
c1f9a359e8
Correctly reset bestMoveChanges
...
for searches not using time management (e.g. analysis, fixed node game play etc),
bestMoveChanges was not reset during search iterations. As LMR uses this quantity,
search was somewhat weaker.
Tested using fixed node playing games:
```
./c-chess-cli -each nodes=10000 option.Hash=16 -engine cmd=../Stockfish/src/fix -engine cmd=../Stockfish/src/master -concurrency 6 -openings file=../books/UHO_XXL_+0.90_+1.19.epd -games 10000
Score of Stockfish Fix vs Stockfish Master: 3187 - 3028 - 3785 [0.508] 10000
./c-chess-cli -each nodes=30000 option.Hash=16 -engine cmd=../Stockfish/src/fix -engine cmd=../Stockfish/src/master -concurrency 6 -openings file=../books/UHO_XXL_+0.90_+1.19.epd -games 10000
Score of Stockfish Fix vs Stockfish Master: 2946 - 2834 - 4220 [0.506] 10000
```
closes https://github.com/official-stockfish/Stockfish/pull/3818
bench: 5061979
2021-12-01 18:22:44 +01:00
bmc4 and Joost VandeVondele
95a2ac1e07
Simplify reduction on rootNode when bestMoveChanges is high
...
The reduction introduced in #3736 also consider on rootNode, so we don't have to reduce again.
STC:
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 28736 W: 7494 L: 7329 D: 13913
Ptnml(0-2): 95, 3247, 7503, 3444, 79
https://tests.stockfishchess.org/tests/view/61a3abe01b7fdf52228e74d8
LTC:
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 47816 W: 12434 L: 12308 D: 23074
Ptnml(0-2): 37, 4972, 13755, 5116, 28
https://tests.stockfishchess.org/tests/view/61a3c3e39f0c43dae1c71d71
closes https://github.com/official-stockfish/Stockfish/pull/3817
bench: 6331638
2021-12-01 18:10:51 +01:00
pb00067 and Joost VandeVondele
282644f141
Remove depth dependence and use same limit (2000) as stat_bonus
...
STC:
https://tests.stockfishchess.org/tests/view/619df59dc0a4ea18ba95a424
LLR: 2.96 (-2.94,2.94) <-2.25,0.25>
Total: 83728 W: 21329 L: 21242 D: 41157
Ptnml(0-2): 297, 9669, 21847, 9752, 299
LTC:
https://tests.stockfishchess.org/tests/view/619e64d7c0a4ea18ba95a475
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 79888 W: 20238 L: 20155 D: 39495
Ptnml(0-2): 57, 8391, 22980, 8444, 73
closes https://github.com/official-stockfish/Stockfish/pull/3806
bench: 6792010
2021-12-01 17:55:23 +01:00
noobpwnftw and Stéphane Nicolet
ca3c1c5f3a
Enable compilation on older Windows systems
...
Improve compatibility of the last NUMA patch when running under older versions of Windows,
for instance Windows Server 2003. Reported by user "g3g6" in the following comments:
https://github.com/official-stockfish/Stockfish/commit/7218ec4df9fef1146a451b71f0ed3bfd8123c9f9
Closes https://github.com/official-stockfish/Stockfish/pull/3821
No functional change
2021-11-30 20:57:47 +01:00
Michael Chaly and Joost VandeVondele
af050e5eed
Refine futility pruning for parent nodes
...
This patch is a result of refining of tuning vondele did after
new net passed and some hand-made values adjustements - excluding
changes in other pruning heuristics and rounding value of history
divisor to the nearest power of 2.
With this patch futility pruning becomes more aggressive and
history influence on it is doubled again.
passed STC
https://tests.stockfishchess.org/tests/view/61a2c4c1a26505c2278c150d
LLR: 2.94 (-2.94,2.94) <0.00,2.50>
Total: 33848 W: 8841 L: 8574 D: 16433
Ptnml(0-2): 100, 3745, 8988, 3970, 121
passed LTC
https://tests.stockfishchess.org/tests/view/61a327ffa26505c2278c26d9
LLR: 2.94 (-2.94,2.94) <0.50,3.00>
Total: 22272 W: 5856 L: 5614 D: 10802
Ptnml(0-2): 12, 2230, 6412, 2468, 14
closes https://github.com/official-stockfish/Stockfish/pull/3814
bench 6302543
2021-11-28 14:25:06 +01:00
Michael Chaly and Joost VandeVondele
8bb5a436b2
Adjust usage of history in futility pruning
...
This patch refines 0ac8aca893https://tests.stockfishchess.org/tests/view/61a156829e83391467a2b2c9
LLR: 2.94 (-2.94,2.94) <0.00,2.50>
Total: 68464 W: 17920 L: 17587 D: 32957
Ptnml(0-2): 239, 7711, 18025, 7992, 265
passed LTC
https://tests.stockfishchess.org/tests/view/61a1bde99e83391467a2b305
LLR: 2.95 (-2.94,2.94) <0.50,3.00>
Total: 26088 W: 6926 L: 6674 D: 12488
Ptnml(0-2): 18, 2619, 7531, 2845, 31
closes https://github.com/official-stockfish/Stockfish/pull/3812
bench 6804653
2021-11-27 14:47:46 +01:00
Michael Chaly and Joost VandeVondele
0ac8aca893
Use fraction of history heuristics in futility pruning
...
This idea is somewhat of a respin of smth we had in futility pruning and that was simplified away - dependence of it not only on static evaluation of position but also on move history heuristics.
Instead of aborting it when they are high there we use fraction of their sum to adjust static eval pruning criteria.
passed STC
https://tests.stockfishchess.org/tests/view/619bd438c0a4ea18ba95a27d
LLR: 2.93 (-2.94,2.94) <0.00,2.50>
Total: 113704 W: 29284 L: 28870 D: 55550
Ptnml(0-2): 357, 12884, 30044, 13122, 445
passed LTC
https://tests.stockfishchess.org/tests/view/619cb8f0c0a4ea18ba95a334
LLR: 2.96 (-2.94,2.94) <0.50,3.00>
Total: 147136 W: 37307 L: 36770 D: 73059
Ptnml(0-2): 107, 15279, 42265, 15804, 113
closes https://github.com/official-stockfish/Stockfish/pull/3805
bench 6777918
2021-11-25 19:38:03 +01:00
Stefan Geschwentner and Stéphane Nicolet
092b27a6d0
Less futility pruning.
...
Disable futility pruning at former PV nodes stored in the transposition table.
STC:
LLR: 2.96 (-2.94,2.94) <0.00,2.50>
Total: 102256 W: 25708 L: 25318 D: 51230
Ptnml(0-2): 276, 11511, 27168, 11893, 280
https://tests.stockfishchess.org/tests/view/61990b3135c7c6348cb602db
LTC:
LLR: 2.96 (-2.94,2.94) <0.50,3.00>
Total: 183304 W: 46027 L: 45408 D: 91869
Ptnml(0-2): 96, 19029, 52778, 19658, 91
https://tests.stockfishchess.org/tests/view/619a0d1b35c7c6348cb603bc
closes https://github.com/official-stockfish/Stockfish/pull/3804
Bench: 7334766
2021-11-23 21:23:28 +01:00
Stéphane Nicolet
a5a89b27c8
Introduce Optimism
...
Current master implements a scaling of the raw NNUE output value with a formula
equivalent to 'eval = alpha * NNUE_output', where the scale factor alpha varies
between 1.8 (for early middle game) and 0.9 (for pure endgames). This feature
allows Stockfish to keep material on the board when she thinks she has the advantage,
and to seek exchanges and simplifications when she thinks she has to defend.
This patch slightly offsets the turning point between these two strategies, by adding
to Stockfish's evaluation a small "optimism" value before actually doing the scaling.
The effect is that SF will play a little bit more risky, trying to keep the tension a
little bit longer when she is defending, and keeping even more material on the board
when she has an advantage.
We note that this patch is similar in spirit to the old "Contempt" idea we used to have
in classical Stockfish, but this implementation differs in two key points:
a) it has been tested as an Elo-gainer against master;
b) the values output by the search are not changed on average by the implementation
(in other words, the optimism value changes the tension/exchange strategy, but a
displayed value of 1.0 pawn has the same signification before and after the patch).
See the old comment https://github.com/official-stockfish/Stockfish/pull/1361#issuecomment-359165141
for some images illustrating the ideas.
-------
finished yellow at STC:
LLR: -2.94 (-2.94,2.94) <0.00,2.50>
Total: 165048 W: 41705 L: 41611 D: 81732
Ptnml(0-2): 565, 18959, 43245, 19327, 428
https://tests.stockfishchess.org/tests/view/61942a3dcd645dc8291c876b
passed LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.00>
Total: 121656 W: 30762 L: 30287 D: 60607
Ptnml(0-2): 87, 12558, 35032, 13095, 56
https://tests.stockfishchess.org/tests/view/61962c58cd645dc8291c8877
-------
How to continue from there?
a) the shape (slope and amplitude) of the sigmoid used to compute the optimism value
could be tweaked to try to gain more Elo, so the parameters of the sigmoid function
in line 391 of search.cpp could be tuned with SPSA. Manual tweaking is also possible
using this Desmos page: https://www.desmos.com/calculator/jhh83sqq92
b) in a similar vein, with two recents patches affecting the scaling of the NNUE
evaluation in evaluate.cpp, now could be a good time to try a round of SPSA tuning
of the NNUE network;
c) this patch will tend to keep tension in middlegame a little bit longer, so any
patch improving the defensive aspect of play via search extensions in risky,
tactical positions would be welcome.
-------
closes https://github.com/official-stockfish/Stockfish/pull/3797
Bench: 6184852
2021-11-21 21:18:08 +01:00
Michael Chaly and Joost VandeVondele
f5df517145
Simplify Pv nodes related logic in LMR
...
Instead of having 2 separate conditions for Pv nodes reductions we can actually write them together. Despite it's not being strictly logically the same bench actually doesn't change up to depth 20, so them interacting is really rare and thus it's just a removal of extra PvNode check most of the time.
passed STC:
https://tests.stockfishchess.org/tests/view/618ce27cd7a085ad008ef4e9
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 37488 W: 9424 L: 9279 D: 18785
Ptnml(0-2): 90, 3903, 10634, 4006, 111
passed LTC:
https://tests.stockfishchess.org/tests/view/618d2585d7a085ad008ef527
LLR: 2.95 (-2.94,2.94) <-2.25,0.25>
Total: 49968 W: 12449 L: 12331 D: 25188
Ptnml(0-2): 27, 4745, 15309, 4889, 14
closes https://github.com/official-stockfish/Stockfish/pull/3792
Bench: 6339548
2021-11-15 18:20:10 +01:00
bmc4 and Stéphane Nicolet
c4a1390f4e
Simplify away the Reverse Move penalty
...
This simplifies the penalty for reverse move introduced in
https://github.com/official-stockfish/Stockfish/pull/2294 .
STC:
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 81696 W: 20627 L: 20540 D: 40529
Ptnml(0-2): 221, 9390, 21559, 9437, 241
https://tests.stockfishchess.org/tests/view/618810acd7a085ad008ef1cc
LTC:
LLR: 2.95 (-2.94,2.94) <-2.25,0.25>
Total: 44136 W: 11021 L: 10890 D: 22225
Ptnml(0-2): 28, 4570, 12746, 4691, 33
https://tests.stockfishchess.org/tests/view/61885686d7a085ad008ef20b
closes https://github.com/official-stockfish/Stockfish/pull/3781
bench: 6547978
2021-11-08 13:14:18 +01:00
Joost VandeVondele and Stéphane Nicolet
7b278aab9f
Reduce use of lazyEval
...
In case the evaluation at root is large, discourage the use of lazyEval.
This fixes https://github.com/official-stockfish/Stockfish/issues/3772
or at least improves it significantly. In this case, poor play with large
odds can be observed, in extreme cases leading to a loss despite large
advantage:
r1bq1b1r/ppp3p1/3p1nkp/n3p3/2B1P2N/2NPB3/PPP2PPP/R3K2R b KQ - 5 9
With this patch the poor move is only considered up to depth 13, in master
up to depth 28.
The patch did not pass at LTC with Elo gainer bounds, but with slightly
positive Elo nevertheless (95% LOS).
STC:
LLR: 2.94 (-2.94,2.94) <0.00,2.50>
Total: 40368 W: 10318 L: 10041 D: 20009
Ptnml(0-2): 103, 4493, 10725, 4750, 113
https://tests.stockfishchess.org/tests/view/61800ad259e71df00dcc420d
LTC:
LLR: -2.94 (-2.94,2.94) <0.50,3.00>
Total: 212288 W: 52997 L: 52692 D: 106599
Ptnml(0-2): 112, 22038, 61549, 22323, 122
https://tests.stockfishchess.org/tests/view/618050d959e71df00dcc426d
closes https://github.com/official-stockfish/Stockfish/pull/3780
Bench: 7127040
2021-11-08 13:03:52 +01:00
Stefan Geschwentner and Joost VandeVondele
a0259d8ab9
Tweak initial aspiration window.
...
Maintain for each root move an exponential average of the search value with a weight ratio of 2:1 (new value vs old values). Then the average score is used as the center of the initial aspiration window instead of the previous score.
Stats indicate (see PR) that the deviation for previous score is in general greater than using average score, so later seems a better estimation of the next search value. This is probably the reason this patch succeded besides smoothing the sometimes wild swings in search score. An additional observation is that at higher depth previous score is above but average score below zero. So for average score more/less fail/low highs should be occur than previous score.
STC:
LLR: 2.97 (-2.94,2.94) <0.00,2.50>
Total: 59792 W: 15106 L: 14792 D: 29894
Ptnml(0-2): 144, 6718, 15869, 7010, 155
https://tests.stockfishchess.org/tests/view/61841612d7a085ad008eef06
LTC:
LLR: 2.94 (-2.94,2.94) <0.50,3.00>
Total: 46448 W: 11835 L: 11537 D: 23076
Ptnml(0-2): 21, 4756, 13374, 5050, 23
https://tests.stockfishchess.org/tests/view/618463abd7a085ad008eef3e
closes https://github.com/official-stockfish/Stockfish/pull/3776
Bench: 6719976
2021-11-05 22:22:30 +01:00
Joost VandeVondele
45e5e65a28
do not store qsearch positions in TT as exact.
...
in qsearch don't store positions in TT with the exact flag.
passed STC:
https://tests.stockfishchess.org/tests/view/617f9a29af49befdeee40231
LLR: 2.95 (-2.94,2.94) <-2.25,0.25>
Total: 155568 W: 39003 L: 39022 D: 77543
Ptnml(0-2): 403, 17854, 41305, 17803, 419
passed LTC:
https://tests.stockfishchess.org/tests/view/6180d47259e71df00dcc42a5
LLR: 2.94 (-2.94,2.94) <-2.25,0.25>
Total: 79640 W: 19993 L: 19910 D: 39737
Ptnml(0-2): 37, 8356, 22957, 8427, 43
closes https://github.com/official-stockfish/Stockfish/pull/3775
Bench: 7531210
2021-11-05 22:20:37 +01:00
Michael Chaly and Joost VandeVondele
c2b9134c6e
Do more reductions at Pv nodes with low delta
...
This patch increases reduction for PvNodes that have their delta (difference between beta and alpha) significantly reduced compared to what it was at root.
passed STC
https://tests.stockfishchess.org/tests/view/617f9063af49befdeee40226
LLR: 2.94 (-2.94,2.94) <0.00,2.50>
Total: 220840 W: 55752 L: 55150 D: 109938
Ptnml(0-2): 583, 24982, 58712, 25536, 607
passed LTC
https://tests.stockfishchess.org/tests/view/61815de959e71df00dcc42ed
LLR: 2.95 (-2.94,2.94) <0.50,3.00>
Total: 79000 W: 19937 L: 19562 D: 39501
Ptnml(0-2): 36, 8190, 22674, 8563, 37
closes https://github.com/official-stockfish/Stockfish/pull/3774
bench: 6717808
2021-11-05 22:18:59 +01:00
lonfom169 and Joost VandeVondele
11c6cf720d
More futility pruning
...
Expand maximum allowed eval by 50% in futility pruning, above the VALUE_KNOWN_WIN.
STC:
LLR: 2.95 (-2.94,2.94) <-0.50,2.50>
Total: 128208 W: 32534 L: 32192 D: 63482
Ptnml(0-2): 298, 13484, 36216, 13790, 316
https://tests.stockfishchess.org/tests/view/6179c069a9b1d8fbcc4ee716
LTC:
LLR: 2.96 (-2.94,2.94) <0.50,3.50>
Total: 89816 W: 22645 L: 22265 D: 44906
Ptnml(0-2): 41, 8404, 27650, 8760, 53
https://tests.stockfishchess.org/tests/view/617ad728f411ea45cc39f895
closes https://github.com/official-stockfish/Stockfish/pull/3767
bench: 6804175
2021-11-05 22:15:53 +01:00
xefoci7612 and Joost VandeVondele
ef4822aa8d
Simplify Skill implementation
...
Currently we handle the UCI_Elo with a double randomization. This
seems not necessary and a bit involuted.
This patch removes the first randomization and unifies the 2 cases.
closes https://github.com/official-stockfish/Stockfish/pull/3769
No functional change.
2021-10-31 22:43:38 +01:00
Stefan Geschwentner and Joost VandeVondele
a8330d5c3b
Do more deeper LMR searches.
...
At expected cut nodes allow at least one ply deeper LMR search for the first seventh moves.
STC:
LLR: 2.93 (-2.94,2.94) <-0.50,2.50>
Total: 42880 W: 10964 L: 10738 D: 21178
Ptnml(0-2): 105, 4565, 11883, 4773, 114
https://tests.stockfishchess.org/tests/view/6179abd7a9b1d8fbcc4ee6f4
LTC:
LLR: 2.93 (-2.94,2.94) <0.50,3.50>
Total: 66872 W: 16930 L: 16603 D: 33339
Ptnml(0-2): 36, 6509, 20024, 6826, 41
https://tests.stockfishchess.org/tests/view/617a30fb2fbca9ca65972b5e
closes https://github.com/official-stockfish/Stockfish/pull/3770
Bench: 6295536
2021-10-31 22:31:55 +01:00
Joost VandeVondele
717d6c5ed5
Widen the aspiration window for larger evals
...
passed STC
LLR: 2.93 (-2.94,2.94) <-0.50,2.50>
Total: 36840 W: 9359 L: 9134 D: 18347
Ptnml(0-2): 111, 4130, 9722, 4337, 120
https://tests.stockfishchess.org/tests/view/617c601301c6d0988731d10a
passed LTC
LLR: 2.98 (-2.94,2.94) <0.50,3.50>
Total: 64824 W: 16377 L: 16043 D: 32404
Ptnml(0-2): 27, 6712, 18618, 7010, 45
https://tests.stockfishchess.org/tests/view/617c720d01c6d0988731d114
closes https://github.com/official-stockfish/Stockfish/pull/3768
Bench: 7683058
2021-10-31 22:30:01 +01:00
Stefan Geschwentner and Stéphane Nicolet
8557f35aa5
Double extend search even more via LMR
...
Allow now for the first five moves a two plies deeper LMR search.
STC:
LLR: 2.96 (-2.94,2.94) <-2.50,0.50>
Total: 99608 W: 25143 L: 25115 D: 49350
Ptnml(0-2): 291, 11444, 26328, 11428, 313
https://tests.stockfishchess.org/tests/view/61718c9438cb9784038af8d7
LTC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 52064 W: 13234 L: 13145 D: 25685
Ptnml(0-2): 35, 5431, 15014, 5514, 38
https://tests.stockfishchess.org/tests/view/6171e13e38cb9784038af928
closes https://github.com/official-stockfish/Stockfish/pull/3760
Bench: 7222293
2021-10-24 22:13:47 +02:00
bmc4 and Stéphane Nicolet
1163d972a9
Simplify LMR multiThread condition
...
STC (8 threads):
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 110584 W: 27818 L: 27807 D: 54959
Ptnml(0-2): 156, 12089, 30791, 12100, 156
https://tests.stockfishchess.org/tests/view/6172ef436ce927be325583a9
LTC (8 threads):
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 23632 W: 6025 L: 5903 D: 11704
Ptnml(0-2): 5, 2292, 7100, 2414, 5
https://tests.stockfishchess.org/tests/view/6173cf096ce927be32558412
closes https://github.com/official-stockfish/Stockfish/pull/3757
No functional change (in the single-threaded case)
Bench: 6689428
2021-10-24 22:08:28 +02:00
FauziAkram and Joost VandeVondele
fc8213c7df
Tuning of a Null Move Parameter
...
STC:
LLR: 2.99 (-2.94,2.94) <-0.50,2.50>
Total: 78744 W: 19956 L: 19664 D: 39124
Ptnml(0-2): 259, 9005, 20573, 9255, 280
https://tests.stockfishchess.org/tests/view/6172017a38cb9784038af947
LTC:
LLR: 2.95 (-2.94,2.94) <0.50,3.50>
Total: 68528 W: 17309 L: 16964 D: 34255
Ptnml(0-2): 41, 7194, 19455, 7527, 47
https://tests.stockfishchess.org/tests/view/6172994d38cb9784038af983
closes https://github.com/official-stockfish/Stockfish/pull/3756
bench: 6689428
2021-10-23 12:27:32 +02:00
bmc4 and Joost VandeVondele
927a84d310
Increase TTdepth acceptance some Threads
...
Increase TTdepth acceptance only on half of the Threads
STC:
LLR: 2.96 (-2.94,2.94) <-0.50,2.50>
Total: 19272 W: 4956 L: 4766 D: 9550
Ptnml(0-2): 25, 1989, 5423, 2169, 30
https://tests.stockfishchess.org/tests/view/6172be6238cb9784038af9a7
LTC:
LLR: 2.93 (-2.94,2.94) <0.50,3.50>
Total: 23688 W: 6111 L: 5897 D: 11680
Ptnml(0-2): 2, 2275, 7081, 2479, 7
https://tests.stockfishchess.org/tests/view/6172e32938cb9784038af9c7
closes https://github.com/official-stockfish/Stockfish/pull/3754
No functional change in the single-threaded case
2021-10-23 12:23:29 +02:00
Stefan Geschwentner and Stéphane Nicolet
8a8640a761
Double extend more often via LMR
...
Allow for first three moves always a two plies deeper LMR search.
STC:
LLR: 2.96 (-2.94,2.94) <-2.50,0.50>
Total: 206096 W: 51966 L: 52093 D: 102037
Ptnml(0-2): 664, 23817, 54293, 23530, 744
https://tests.stockfishchess.org/tests/view/616f197d40f619782fd4f75a
LTC:
LLR: 2.93 (-2.94,2.94) <-2.50,0.50>
Total: 62384 W: 15567 L: 15492 D: 31325
Ptnml(0-2): 40, 6633, 17777, 6696, 46
https://tests.stockfishchess.org/tests/view/616ffa1b4f0b65a0e231e682
closes https://github.com/official-stockfish/Stockfish/pull/3752
Bench: 6154836
2021-10-21 12:42:30 +02:00
bmc4 and Stéphane Nicolet
42a895d9c9
Simplify null move search condition
...
Remove `ss->ttPv` condition on null move search condition
STC:
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 80832 W: 20276 L: 20221 D: 40335
Ptnml(0-2): 267, 9335, 21168, 9368, 278
https://tests.stockfishchess.org/tests/view/616ed4a0942d40685e3237c6
LTC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 54184 W: 13464 L: 13377 D: 27343
Ptnml(0-2): 37, 5758, 15435, 5805, 57
https://tests.stockfishchess.org/tests/view/616ef71f40f619782fd4f72d
closes https://github.com/official-stockfish/Stockfish/pull/3750
bench: 6201607
2021-10-21 08:43:43 +02:00
bmc4 and Joost VandeVondele
4af1ae82c6
Adjust TTdepth acceptance on early cutoff
...
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 63784 W: 16185 L: 15917 D: 31682
Ptnml(0-2): 231, 7309, 16531, 7603, 218
https://tests.stockfishchess.org/tests/view/616ed03a942d40685e3237c0
LTC:
LLR: 2.93 (-2.94,2.94) <0.50,3.50>
Total: 12728 W: 3268 L: 3072 D: 6388
Ptnml(0-2): 8, 1298, 3563, 1480, 15
https://tests.stockfishchess.org/tests/view/616ef156942d40685e32380a
closes https://github.com/official-stockfish/Stockfish/pull/3748
bench: 7050445
2021-10-19 22:14:39 +02:00
bmc4 and Joost VandeVondele
b37054c310
Simplify evaluate condition on search
...
Remove condition for MOVE_NULL on search.
STC:
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 47544 W: 11968 L: 11864 D: 23712
Ptnml(0-2): 150, 5535, 12318, 5599, 170
https://tests.stockfishchess.org/tests/view/616e37143799eb91f1f071ee
LTC:
LLR: 2.93 (-2.94,2.94) <-2.50,0.50>
Total: 67472 W: 16938 L: 16870 D: 33664
Ptnml(0-2): 49, 7119, 19331, 7189, 48
https://tests.stockfishchess.org/tests/view/616e3fab3799eb91f1f071f1
closes https://github.com/official-stockfish/Stockfish/pull/3746
bench: 5255771
2021-10-19 22:09:47 +02:00
bmc4 and Stéphane Nicolet
67d0616483
Simplify probCutCount away
...
Simplify away the limitation in number of moves in probCut.
STC:
LLR: 2.96 (-2.94,2.94) <-2.50,0.50>
Total: 286768 W: 71888 L: 72133 D: 142747
Ptnml(0-2): 983, 33084, 75471, 32887, 959
https://tests.stockfishchess.org/tests/view/616c9b9b90e1312a3cd0ef0a
LTC:
LLR: 2.95 (-2.94,2.94) <-2.50,0.50>
Total: 69312 W: 17243 L: 17176 D: 34893
Ptnml(0-2): 42, 7452, 19614, 7493, 55
https://tests.stockfishchess.org/tests/view/616cebbf4f95b438f7a85f93
closes https://github.com/official-stockfish/Stockfish/pull/3745
bench: 5005810
2021-10-18 21:00:08 +02:00
Stéphane Nicolet
8a74c08928
Remove noLMRExtension flag
...
This simplification patch removes the noLMRExtension flag. It was introduced in June
(see following link for that commit), but does not seem to be necessary anymore.
Link: https://github.com/official-stockfish/Stockfish/commit/e1f181ee643dcaa92c606b74b3abd23dede136cd
STC:
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 21200 W: 5369 L: 5228 D: 10603
Ptnml(0-2): 67, 2355, 5616, 2494, 68
https://tests.stockfishchess.org/tests/view/616c03d299b580bf37797dcb
LTC:
LLR: 2.94 (-2.94,2.94) <-2.50,0.50>
Total: 37536 W: 9387 L: 9278 D: 18871
Ptnml(0-2): 23, 3988, 10643, 4085, 29
https://tests.stockfishchess.org/tests/view/616c10f499b580bf37797ddd
closes https://github.com/official-stockfish/Stockfish/pull/3743
Bench: 4792969
2021-10-17 17:54:39 +02:00
Stéphane Nicolet and Joost VandeVondele
6847be2c75
Allow some LMR double extensions
...
Allow some LMR double extensions for the second and third sons of each node.
STC:
LLR: 2.94 (-2.94,2.94) <-0.50,2.50>
Total: 170320 W: 42608 L: 42187 D: 85525
Ptnml(0-2): 516, 19635, 44422, 20086, 501
https://tests.stockfishchess.org/tests/view/616a9e3899b580bf37797cf4
LTC:
LLR: 2.93 (-2.94,2.94) <0.50,3.50>
Total: 74400 W: 18783 L: 18423 D: 37194
Ptnml(0-2): 46, 7812, 21129, 8162, 51
https://tests.stockfishchess.org/tests/view/616b378499b580bf37797d61
closes https://github.com/official-stockfish/Stockfish/pull/3742
Bench: 4877152
2021-10-17 12:29:11 +02:00
Stefano Cardanobile and Stéphane Nicolet
4231d99ab4
Smooth improving
...
Smooth dependency on improvement margin in null move search.
STC
LLR: 2.93 (-2.94,2.94) <-0.50,2.50>
Total: 17384 W: 4468 L: 4272 D: 8644
Ptnml(0-2): 42, 1919, 4592, 2079, 60
https://tests.stockfishchess.org/tests/view/61689b8a1e5f6627cc1c0fdc
LTC
LLR: 2.94 (-2.94,2.94) <0.50,3.50>
Total: 45648 W: 11525 L: 11243 D: 22880
Ptnml(0-2): 26, 4731, 13036, 4997, 34
https://tests.stockfishchess.org/tests/view/6168a12c1e5f6627cc1c0fe3
It would be interesting to test if the other pruning/reduction heuristics
in master which are using the improving variable (ie the sign of improvement)
could benefit from a smooth function of the improvement value (or maybe a
Relu of the improvement value).
closes https://github.com/official-stockfish/Stockfish/pull/3740
Bench: 4916775
2021-10-15 14:57:01 +02:00
