lc0 truncated VerboseMoveStats output

[SimonBenhamou]

Hello,

I would like to access lc0 detailed policy, which looks like this in the UCI engine:

info string g1h1  (153 ) N:       0 (+ 0) (P:  0.10%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.01526) (S: -0.35020) (V:  -.----) 
info string g2d5  (380 ) N:       0 (+ 0) (P:  0.10%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.01558) (S: -0.34987) (V:  -.----) 
info string h6f8  (1377) N:       0 (+ 0) (P:  0.13%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.02019) (S: -0.34526) (V:  -.----) 
info string d3a6  (526 ) N:       0 (+ 0) (P:  0.17%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.02703) (S: -0.33843) (V:  -.----) 
info string g2g6  (383 ) N:       0 (+ 0) (P:  0.17%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.02764) (S: -0.33781) (V:  -.----) 
info string g2f3  (373 ) N:       0 (+ 0) (P:  0.18%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.02918) (S: -0.33627) (V:  -.----) 
info string h6f4  (1361) N:       0 (+ 0) (P:  0.20%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.03159) (S: -0.33386) (V:  -.----) 
info string d3b5  (521 ) N:       0 (+ 0) (P:  0.22%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.03500) (S: -0.33046) (V:  -.----) 
info string g2h1  (364 ) N:       0 (+ 0) (P:  0.23%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.03577) (S: -0.32969) (V:  -.----) 
info string d3f1  (503 ) N:       0 (+ 0) (P:  0.25%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.04028) (S: -0.32517) (V:  -.----) 
info string b3b4  (453 ) N:       0 (+ 0) (P:  0.28%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.04385) (S: -0.32160) (V:  -.----) 
info string d1b1  (73  ) N:       0 (+ 0) (P:  0.28%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.04417) (S: -0.32128) (V:  -.----) 
info string h6d2  (1357) N:       0 (+ 0) (P:  0.29%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.04621) (S: -0.31924) (V:  -.----) 
info string g1f1  (152 ) N:       0 (+ 0) (P:  0.31%) (WL:  -.-----) (D: -.---) (M:  -.-) (Q: -0.36545) (U: 0.04848) (S: -0.31697) (V:  -.----) 

I use the following code to interact with the engine:

maia_model_path = 'maia_models/maia-1100.pb'
if 'maia_engine' in locals():
    maia_engine.quit()
maia_engine = chess.engine.SimpleEngine.popen_uci(['lc0/build/release/lc0', 
                                                   '-w', maia_model_path,
                                                   ])
maia_engine.configure({
    "WeightsFile": maia_model_path,
    "UCI_ShowWDL": True,
    # 'ScoreType': 'win_percentage',
    "NNCacheSize": "0",
    "PolicyTemperature": 1.0,
    # "HistoryFill": "fen_only",
    "PerPVCounters": "True",
    "VerboseMoveStats": "True",
    "CacheHistoryLength": 0
    # "Noise": "False",
})

board = chess.Board(fen='r5k1/1pp2p1p/p1qpr1pB/4p2P/3n4/1P1B4/n1P2PQP/3RK1R1 w - - 1 19')
maia_analysis = maia_engine.analyse(board, chess.engine.Limit(depth=5))

But the way the python chess module parses the lc0 outputs is problematic: I get a single value in the 'string' key of the maia analysis:

'string': 'node ( 42) N: 117 (+48) (P: 78.63%) (WL: -0.09076) (D: 0.138) (M: 4.4) (Q: -0.09076) (V: -.----) '}

It looks like the 'string' attribute is overwritten for each line starting with "info string" in the UCI engine... Is there any way to capture the full output directly ?

[niklasf]

Hi. You can use maia_engine.analysis(...) as in the following example to observe every bit of information coming from the engine: https://python-chess.readthedocs.io/en/latest/engine.html#indefinite-or-infinite-analysis