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DefenceTest mathematics

Owen Foundation edited this page Sep 20, 2026 · 1 revision

DefenceTest mathematics

SPRT

Strength tests use the Sequential Probability Ratio Test: games stream in until the evidence crosses an upper bound (accept: patch is stronger) or a lower bound (reject). Bounds come from the requested Elo window, e.g. [0, 5] means "prove +5 Elo or stop". SPRT needs far fewer games than a fixed game count for the same confidence.

Elo model

Results are scored pentanomially (pairs of games: WW, WD+DW, WL+LW, DD, LL…) which halves variance versus trinomial scoring. Elo differences and error bars derive from the pentanomial likelihood.

SPSA

Parameter tuning runs use Simultaneous Perturbation Stochastic Approximation; the mathematics behind it is covered in https://github.com/vdbergh/spsa_simul (see doc/theoretical_basis.pdf).

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