Run T-0020 failed

· Evidence: SPRT Sequential probability ratio test. Games are played until the accumulated evidence reaches one of two bounds; then the test stops.

Hypothesis

The engine should play more strongly because it will preserve winnable minor-piece endings, recognize repetitions despite irrelevant en-passant fields, and keep halfmove- and path-dependent draw scores from contaminating the transposition table.

Stages

Elo against the predecessorElo intervals: short stage −20.67 ± 10.40.−30−20−100short stage−20.67 ± 10.40short stage · failed−20.67 ± 10.40 Elo · 2,390 games
Point estimate with the reported 95-percent half-width, per stage. The dashed line is zero. Estimates from a stopped sequential test are biased by the stopping rule; the interval is nominal.
Field short stage
Verdictfailed
Elo Strength difference to the opponent, estimated from the games, with a 95-percent half-width where the oracle reported one. Never an absolute rating.−20.67 ± 10.40
nElo Normalised Elo: the Elo difference divided by the spread of the game results, so that the SPRT bounds mean the same at different time controls.−27.76 ± 13.93
Games2,390
Wins / draws / losses849 / 550 / 991
pentanomial Games are played in pairs with swapped colours; the five counts are the pairs scoring 0, ½, 1, 1½ and 2 points.142 / 220 / 565 / 174 / 94
LLR Log-likelihood ratio, the running evidence of an SPRT. It starts at 0; a stage passes at the upper bound (about +2.94) and fails at the lower one (about −2.94).−2.98
Bounds−2.94 … +2.94
SPRT Sequential probability ratio test. Games are played until the accumulated evidence reaches one of two bounds; then the test stops.[0.0, 5.0]
Error rates α / β0.05 / 0.05
Modelnormalized
time control Base time plus increment per move in seconds, e.g. 8+0.08: eight seconds per game plus 0.08 seconds per move.8+0.08
BookA
Opponentvs predecessor
Duration12 min

Provenance

Date
2026-08-29
Started
2026-08-29 05:03:58 UTC
Duration
12 min
Author
Agent B
Bench nodes
5,073
Commit
e0fce07f54c762efe78e3599a8656f15cc2f4927
SHA-256 A cryptographic hash. The same bytes always give the same hash, so a hash identifies exactly one version of a file or binary.
204b6fa28105b771b7ab0e13d52c41fce407aa00ce01559446bc59b1400593f9