- Capitalize comments
- Reformat multi-lines comments to equalize the widths of the lines
- Try to keep the width of comments around 85 characters
- Remove periods at the end of single-line comments
closes https://github.com/official-stockfish/Stockfish/pull/5469
No functional change
In probcut move loop, everything is enclosed within a large if statement. I've
changed it to guard clauses to stay consistent with other move loops.
closes https://github.com/official-stockfish/Stockfish/pull/5463
No functional change
Created by modifying L2 weights from the previous main net (nn-74f1d263ae9a.nnue)
with params found by spsa around 9k / 120k games at 120+1.2.
370 spsa params - L2 weights in nn-74f1d263ae9a.nnue where |val| >= 50
A: 6000, alpha: 0.602, gamma: 0.101
weights: [-127, 127], c_end = 6
To print the spsa params with nnue-pytorch:
```
import features
from serialize import NNUEReader
feature_set = features.get_feature_set_from_name("HalfKAv2_hm")
with open("nn-74f1d263ae9a.nnue", "rb") as f:
model = NNUEReader(f, feature_set).model
c_end = 6
for i in range(8):
for j in range(32):
for k in range(30):
value = int(model.layer_stacks.l2.weight[32 * i + j, k] * 64)
if abs(value) >= 50:
print(f"twoW[{i}][{j}][{k}],{value},-127,127,{c_end},0.0020")
```
Among the 370 params, 229 weights were changed.
avg change: 0.0961 ± 1.67
range: [-4, 3]
The number of weights changed, grouped by layer stack index,
shows more weights were modified in the lower piece count buckets:
[54, 52, 29, 23, 22, 18, 14, 17]
Found with the same method described in:
https://github.com/official-stockfish/Stockfish/pull/5459
Passed STC:
https://tests.stockfishchess.org/tests/view/668aec9a58083e5fd88239e7
LLR: 3.00 (-2.94,2.94) <0.00,2.00>
Total: 52384 W: 13569 L: 13226 D: 25589
Ptnml(0-2): 127, 6141, 13335, 6440, 149
Passed LTC:
https://tests.stockfishchess.org/tests/view/668af50658083e5fd8823a0b
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 46974 W: 12006 L: 11668 D: 23300
Ptnml(0-2): 25, 4992, 13121, 5318, 31
closes https://github.com/official-stockfish/Stockfish/pull/5466
bench 1300471
Always use the posix function posix_memalign() as aligned memory
allocator on Apple computers. This should allow to compile Stockfish
out of the box on all versions of Mac OS X.
Patch tested on the following systems (apart from the CI) :
• Mac OS 10.9.6 (arch x86-64-sse41-popcnt) with gcc-10
• Mac OS 10.13.6 (arch x86-64-bmi2) with gcc-10, gcc-14 and clang-11
• Mac OS 14.1.1 (arch apple-silicon) with clang-15
closes https://github.com/official-stockfish/Stockfish/pull/5462
No functional change
Created by setting output weights (256) and biases (8) of the previous main net
nn-ddcfb9224cdb.nnue to values found around 12k / 120k spsa games at 120+1.2
This used modified fishtest dev workers to construct .nnue files from
spsa params, then load them with EvalFile when running tests:
https://github.com/linrock/fishtest/tree/spsa-file-modified-nnue/worker
Inspired by researching loading spsa params from files:
https://github.com/official-stockfish/fishtest/pull/1926
Scripts for modifying nnue files and preparing params:
https://github.com/linrock/nnue-pytorch/tree/no-gpu-modify-nnue
spsa params:
weights: [-127, 127], c_end = 6
biases: [-8192, 8192], c_end = 64
Example of reading output weights and biases from the previous main net using
nnue-pytorch and printing spsa params in a format compatible with fishtest:
```
import features
from serialize import NNUEReader
feature_set = features.get_feature_set_from_name("HalfKAv2_hm")
with open("nn-ddcfb9224cdb.nnue", "rb") as f:
model = NNUEReader(f, feature_set).model
c_end_weights = 6
c_end_biases = 64
for i in range(8):
for j in range(32):
value = round(int(model.layer_stacks.output.weight[i, j] * 600 * 16) / 127)
print(f"oW[{i}][{j}],{value},-127,127,{c_end_weights},0.0020")
for i in range(8):
value = int(model.layer_stacks.output.bias[i] * 600 * 16)
print(f"oB[{i}],{value},-8192,8192,{c_end_biases},0.0020")
```
For more info on spsa tuning params in nets:
https://github.com/official-stockfish/Stockfish/pull/5149https://github.com/official-stockfish/Stockfish/pull/5254
Passed STC:
https://tests.stockfishchess.org/tests/view/66894d64e59d990b103f8a37
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 32000 W: 8443 L: 8137 D: 15420
Ptnml(0-2): 80, 3627, 8309, 3875, 109
Passed LTC:
https://tests.stockfishchess.org/tests/view/6689668ce59d990b103f8b8b
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 172176 W: 43822 L: 43225 D: 85129
Ptnml(0-2): 97, 18821, 47633, 19462, 75
closes https://github.com/official-stockfish/Stockfish/pull/5459
bench 1120091
Currently (after #5407), SF has the property that any PV line with a decisive
TB score contains the corresponding TB position, with a score that correctly
identifies the depth at which TB are entered. The PV line that follows might
not preserve the game outcome, but can easily be verified and extended based on
TB information. This patch provides this functionality, simply extending the PV
lines on output, this doesn't affect search.
Indeed, if DTZ tables are available, search based PV lines that correspond to
decisive TB scores are verified to preserve game outcome, truncating the line
as needed. Subsequently, such PV lines are extended with a game outcome
preserving line until mate, as a possible continuation. These lines are not
optimal mating lines, but are similar to what a user could produce on a website
like https://syzygy-tables.info/ clicking always the top ranked move, i.e.
minimizing or maximizing DTZ (with a simple tie-breaker for moves that have
identical DTZ), and are thus an just an illustration of how to game can be won.
A similar approach is already in established in
https://github.com/joergoster/Stockfish/tree/matefish2
This also contributes to addressing #5175 where SF can give an incorrect TB
win/loss for positions in TB with a movecounter that doesn't reflect optimal
play. While the full solution requires either TB generated differently, or a
search when ranking rootmoves, current SF will eventually find a draw in these
cases, in practice quite quickly, e.g.
`1kq5/q2r4/5K2/8/8/8/8/7Q w - - 96 1`
`8/8/6k1/3B4/3K4/4N3/8/8 w - - 54 106`
Gives the same results as master on an extended set of test positions from
9173d29c41
with the exception of the above mentioned fen where this commit improves.
With https://github.com/vondele/matetrack using 6men TB, all generated PVs verify:
```
Using ../Stockfish/src/stockfish.syzygyExtend on matetrack.epd with --nodes 1000000 --syzygyPath /chess/syzygy/3-4-5-6/WDL:/chess/syzygy/3-4-5-6/DTZ
Engine ID: Stockfish dev-20240704-ff227954
Total FENs: 6555
Found mates: 3299
Best mates: 2582
Found TB wins: 568
```
As repeated DTZ probing could be slow a procedure (100ms+ on HDD, a few ms on
SSD), the extension is only done as long as the time taken is less than half
the `Move Overhead` parameter. For tournaments where these lines might be of
interest to the user, a suitable `Move Overhead` might be needed (e.g. TCEC has
1000ms already).
closes https://github.com/official-stockfish/Stockfish/pull/5414
No functional change
To avoid output that depends on timing, output currmove and similar only from depth > 30
onward. Current choice of 3s makes the output of the same search depending on
the system load, and doesn't always start at move 1. Depth 30 is nowadays
reached in a few seconds on most systems.
closes https://github.com/official-stockfish/Stockfish/pull/5436
No functional change
do not upload some unneeded intermediate directories,
disable running authenticated git commands with the checkout action.
Thanks to Yaron A for the report.
closes https://github.com/official-stockfish/Stockfish/pull/5435
No functional change
Follow up from #5404 ... current location leads to troubles with Aquarium GUI
Fixes#5430
Now prints the information on threads and available processors at the beginning
of search, where info about the networks is already printed (and is known to
work)
closes https://github.com/official-stockfish/Stockfish/pull/5433
No functional change.
This patch introduces history updates to probcut. Standard depth - 3 bonus and
maluses are given to the capture that caused fail high and previously searched
captures, respectively. Similar to #5243, a negative history fill is applied to
compensate for an increase in capture history average, thus improving the
scaling of this patch.
Passed STC:
LLR: 2.95 (-2.94,2.94) <0.00,2.00>
Total: 84832 W: 21941 L: 21556 D: 41335
Ptnml(0-2): 226, 9927, 21688, 10386, 189
https://tests.stockfishchess.org/tests/view/6682fab9389b9ee542b1d029
Passed LTC:
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 104298 W: 26469 L: 26011 D: 51818
Ptnml(0-2): 43, 11458, 28677, 11940, 31
https://tests.stockfishchess.org/tests/view/6682ff06389b9ee542b1d0a0
closes https://github.com/official-stockfish/Stockfish/pull/5428
bench 1281351
this action plays games under fast-chess with a `debug=yes` compiled binary.
It checks for triggered asserts in the code, or generally for engine disconnects.
closes https://github.com/official-stockfish/Stockfish/pull/5403
No functional change
try to avoid missing good moves for opponent or engine, by updating bestMove
also when value == bestValue (i.e. value == alpha) under certain conditions.
In particular require this is at higher depth in the tree, leaving the logic
near the root unchanged, and only apply randomly. Avoid doing this near mate
scores, leaving mate PVs intact.
Passed SMP STC 6+0.06 th7 :
LLR: 2.94 (-2.94,2.94) <0.00,2.00>
Total: 42040 W: 10930 L: 10624 D: 20486
Ptnml(0-2): 28, 4682, 11289, 4998, 23
https://tests.stockfishchess.org/tests/view/66608b00c340c8eed7757d1d
Passed SMP LTC 24+0.24 th7 :
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 73692 W: 18978 L: 18600 D: 36114
Ptnml(0-2): 9, 7421, 21614, 7787, 15
https://tests.stockfishchess.org/tests/view/666095e8c340c8eed7757d49
closes https://github.com/official-stockfish/Stockfish/pull/5367
Bench 1205168
