Bug 1 of the eval-Hold-collapse diagnosis. The fxcache target schema
documented in experience_kernels.cu:1556 + cuda_pipeline/mod.rs:508 specifies:
target[0] = preproc_close — log-return-normalized close (network input)
target[1] = preproc_next — log-return-normalized next close
target[2] = raw_close — raw price for portfolio simulation
target[3] = raw_next — raw price
target[4] = raw_open — raw price
target[5] = mid_price_open — MBP-10 midpoint (fallback raw_open)
Both writers — `precompute_features.rs:360` and `data_loading.rs:510` —
violated the contract by storing raw OHLCV close prices in slots [0:1].
Empirical fxcache inspection: target[0..4] mean=$5967, stddev=$582 (raw
prices throughout). The raw-price values at target[0:1] were never directly
consumed by training (production aux head reads next_states[i][0] = MARKET
feat[0] = log_return), but they corrupted any code reading targets per the
documented contract.
Both writers now compute (raw_curr / prev_close).ln() and (raw_next /
raw_curr).ln() for the preproc columns. FXCACHE_VERSION bumped 7→8 to
invalidate existing caches and trigger ensure-fxcache regen.
A second bug — eval label_scale=5300 (raw price magnitude) at production
binary despite source state[0] tracing back to z-normalized log_return —
remains unresolved. Bug 2 instrumentation lands in the next commit; that
runtime trace will pin which production-binary code path injects raw_close
into state[0] post-gather.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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