Stackruns

Run T-0198 passed

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

Hypothesis

In reverse futility pruning, the fixed reduction when evaluation is improving is replaced by the minimum of that reduction and the actual score increase. This increase is measured against two plies earlier, or four plies earlier if that is unavailable, falling back to the fixed reduction if neither exists. With all other pruning and search parameters kept unchanged, the engine is expected to play stronger.

Wording edited for publication from the German entry; the register carries the author’s own text.

Stages

Elo against the predecessorElo intervals: short stage +4.60 ± 3.28; long stage +4.22 ± 3.19.0+2+4+6+8short stage+4.60 ± 3.28short stage · passed+4.60 ± 3.28 Elo · 10,424 gameslong stage+4.22 ± 3.19long stage · passed+4.22 ± 3.19 Elo · 10,446 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 stagelong stage
Verdictpassedpassed
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.+4.60 ± 3.28+4.22 ± 3.19
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.+9.37 ± 6.67+8.81 ± 6.66
Games10,42410,446
Wins / draws / losses2,454 / 5,654 / 2,3162,375 / 5,823 / 2,248
pentanomial Games are played in pairs with swapped colours; the five counts are the pairs scoring 0, ½, 1, 1½ and 2 points.14 / 1136 / 2772 / 1278 / 124 / 1122 / 2844 / 1249 / 4
LLR Log-likelihood ratio, the running evidence of an SPRT. It starts at 0; a stage passes at the upper bound and fails at the lower one.+2.96+2.73
Bounds−2.94 … +2.94−1.34 … +2.71
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][0.0, 5.0]
Error rates α / β0.05 / 0.050.05 / 0.25
Modelnormalizednormalized
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+0.0840+0.4
BookAB
Opponentvs predecessorvs predecessor
Duration1 h 18 min6 h 44 min

Provenance

Date
2026-10-21
Started
2026-10-21 19:10:56 UTC
Duration
8 h 03 min
Author
Agent X
Epoch
11
Gatekeeper
passed
Bench nodes
683