Implement reverse futility pruning

[brunocodutra]

Gauntlet

cutechess-cli -tournament gauntlet -games 2 -rounds 1500 -openings file=engines/openings-6ply-1000.pgn plies=6 policy=round -concurrency 8 -ratinginterval 10 -resultformat wide -recover -tb engines/syzygy/ -engine conf=dev stderr=stderr.log -engine conf=Frozenight-6.0 -engine conf=Halogen-11.0 -engine conf=Marvin-6.2 -each tc=3+0.025 option.Hash=32 option.Threads=1

Rank Name                          Elo     +/-   Games    Wins  Losses   Draws   Points   Score    Draw 
   0 dev                            29       5    9000    2826    2083    4091   4871.5   54.1%   45.5% 
   1 Frozenight-6.0                -19       9    3000     721     886    1393   1417.5   47.3%   46.4% 
   2 Marvin-6.2                    -29       9    3000     681     933    1386   1374.0   45.8%   46.2% 
   3 Halogen-11.0                  -38       9    3000     681    1007    1312   1337.0   44.6%   43.7%

cutechess-cli -tournament gauntlet -games 2 -rounds 1500 -openings file=engines/openings-6ply-1000.pgn plies=6 policy=round -concurrency 8 -ratinginterval 10 -resultformat wide -recover -engine conf=dev stderr=stderr.log -engine conf=Carp-3.0.1 -engine conf=Winter-4.0 -engine conf=Frozenight-6.0 -each tc=3+0.025 option.Hash=32 option.Threads=1

Rank Name                          Elo     +/-   Games    Wins  Losses   Draws   Points   Score    Draw
   0 dev                            -6       5    9000    2446    2600    3954   4423.0   49.1%   43.9%
   1 Carp-3.0.1                     23      10    3000    1002     800    1198   1601.0   53.4%   39.9%
   2 Winter-4.0                      6       9    3000     835     782    1383   1526.5   50.9%   46.1%
   3 Frozenight-6.0                -12       9    3000     763     864    1373   1449.5   48.3%   45.8%

STS1-STS15_LAN_v6.epd

python sts_rating.py -f "./epd/STS1-STS15_LAN_v6.epd" -e dev -t 8 -h 256 --movetime 100 --maxpoint 100

STS Rating v14.2
Engine: chessboard
Hash: 256, Threads: 8, time/pos: 0.100s

Number of positions in ./epd/STS1-STS15_LAN_v6.epd: 1188
Max score = 1188 x 100 = 118800
Test duration: 00h:02m:30s
Expected time to finish: 00h:02m:34s

  STS ID   STS1   STS2   STS3   STS4   STS5   STS6   STS7   STS8   STS9  STS10  STS11  STS12  STS13  STS14  STS15    ALL
  NumPos     85     80     86     89     85     80     82     80     71     79     70     74     75     79     73   1188
 BestCnt     67     59     64     73     69     55     58     58     42     66     54     53     59     59     43    879
   Score   7622   7115   7641   8375   8051   7579   7299   7057   5892   7472   6449   6509   6701   7113   6496 107371
Score(%)   89.7   88.9   88.8   94.1   94.7   94.7   89.0   88.2   83.0   94.6   92.1   88.0   89.3   90.0   89.0   90.4

:: STS ID and Titles ::
STS 01: Undermining
STS 02: Open Files and Diagonals
STS 03: Knight Outposts
STS 04: Square Vacancy
STS 05: Bishop vs Knight
STS 06: Re-Capturing
STS 07: Offer of Simplification
STS 08: Advancement of f/g/h Pawns
STS 09: Advancement of a/b/c Pawns
STS 10: Simplification
STS 11: Activity of the King
STS 12: Center Control
STS 13: Pawn Play in the Center
STS 14: Queens and Rooks to the 7th rank
STS 15: Avoid Pointless Exchange

:: Top 5 STS with high result ::
1. STS 06, 94.7%, "Re-Capturing"
2. STS 05, 94.7%, "Bishop vs Knight"
3. STS 10, 94.6%, "Simplification"
4. STS 04, 94.1%, "Square Vacancy"
5. STS 11, 92.1%, "Activity of the King"

:: Top 5 STS with low result ::
1. STS 09, 83.0%, "Advancement of a/b/c Pawns"
2. STS 12, 88.0%, "Center Control"
3. STS 08, 88.2%, "Advancement of f/g/h Pawns"
4. STS 03, 88.8%, "Knight Outposts"
5. STS 02, 88.9%, "Open Files and Diagonals"

[codecov]

Codecov Report

Attention: Patch coverage is 88.88889% with 1 line in your changes missing coverage. Please review.

Project coverage is 97.20%. Comparing base (e1af234) to head (e1a9182).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
lib/search/engine.rs	88.88%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #650      +/-   ##
==========================================
- Coverage   97.38%   97.20%   -0.19%     
==========================================
  Files          46       46              
  Lines        3141     3150       +9     
==========================================
+ Hits         3059     3062       +3     
- Misses         82       88       +6     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.