40 lines
2.0 KiB
TeX
40 lines
2.0 KiB
TeX
%% SCRAP: archive/quality/phase-tracking/phase-2-issues-identified
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%% SOURCE: docs/working/archive/quality/phase-tracking/phase-2-issues-identified.md
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%% STATUS: HISTORICAL
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%% FITS: none
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%% EDITORIAL: lifted — prose rewritten to press voice
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\section*{Phase~2 Issues: Fixed-Point Violations, Decay Slope, and Adaptive Window (November 2025)}
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A root-cause analysis conducted on 2025-11-08 identified four critical issues
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blocking Phase~2 validation of the StarForth adaptive physics engine.
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\textbf{Issue~1: Float/Double Violations.}
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Seven locations in \texttt{src/doe\_metrics.c} and three in
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\texttt{src/rolling\_window\_of\_truth.c} used IEEE~754 floating-point
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arithmetic for physics calculations that the architecture mandates be computed
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in Q48.16 fixed-point. Seven fields in \texttt{include/doe\_metrics.h} were
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typed as \texttt{double} rather than \texttt{uint64\_t}. These violations
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contaminated physics calculations and broke compatibility with the Isabelle/HOL
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formal model.
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\textbf{Issue~2: Decay Slope Uninitialized.}
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The \texttt{decay\_slope} field in \texttt{src/doe\_metrics.c} was hardcoded
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to \texttt{0.0}. No mechanism existed to capture dictionary heat at experiment
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start and end, nor to compute the observed slope from those snapshots.
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\textbf{Issue~3: Adaptive Window Non-Responsive.}
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The rolling window effective size was consistently reported as 4096 regardless
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of execution history. Instrumentation was absent, making it impossible to
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determine whether the shrink logic was executing, miscalculating growth rate,
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or measuring diversity incorrectly.
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\textbf{Issue~4: Unidirectional Adaptation.}
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The window-sizing logic shrunk the window when diversity growth fell below 1\%
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but never grew it. Wiring Feedback Loop~4 (prefetch accuracy) into Loop~5
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(window width inference) as a bidirectional binary-chop signal was identified
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as the required architectural addition.
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All four issues were subsequently resolved through the implemented Loop~5 and
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Loop~6 architecture now in production.
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