This is a rather involved merge, since the cluster changes interact
fairly badly with the refactoring we're merging:
The new code wants the search to know nothing at all about the UCI protocol,
it just calls a callback with some worker information (including a Position),
which then transforms that information into a InfoFull which is then sent
through another callback, upon which UCIEngine converts it to UCI and writes
it to stdout.
On the other hand, the MPI information wants to exchange PVs between workers
at this point, and it wants to use the UCI string as the primary medium of
exchange. Position is a lot of work to serialize, so we choose a middle road;
we capture the InfoFull by switching out the callback, serializes it, does the
MPI exchange on that, unserializes it and then continues with the print callback
(if there is new information).
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
https://github.com/mcostalba/Stockfish/commit/9173d29c414ddb8f4bec74e4db3ccbe664c66bf9
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
