mhzs7 reported val mean_auc=0.726 on 3a196382f — but the trainer
constructed both train and val MultiHorizonLoader with the SAME
`mbp10_root: cli.mbp10_data_dir`. The two loaders only differed by
seed. So val sequences were held-out-by-anchor from the same files
train sampled from; not temporally OOS. Per
`pearl_single_window_oos_is_not_oos.md` a single-window result that
doesn't enforce time-ordered separation can collapse across true
walk-forward folds.
Refactor: drop `mbp10_root` from `MultiHorizonLoaderConfig` (which
forced caller to share the dir between train and val). New API takes
an explicit `files: Vec<PathBuf>` — the loader preserves the order
given and does no internal shuffle, so callers control temporal
ordering. Added `discover_mbp10_files_sorted(root)` helper that
enumerates a dir and sorts by filename (chronological under the
`ES.FUT_<YEAR>-Q<n>.dbn.zst` convention).
alpha_train.rs splits the discovered files by 3 new CLI flags:
--cv-fold <k> (default 0)
--cv-n-folds <N> (default 1 — single fold)
--cv-train-window <W> (default 0 — auto)
Single-fold default (cv_n_folds=1): train on all files except the
last, val on the last file. This replaces the old "same files for
both" bug; even runs that don't think about CV now get a temporal
split by default.
Sliding-window CV (cv_n_folds > 1): fold k trains on files
[k..k+W] and validates on file [k+W]. With 9 quarterly files
(2024-Q1..2026-Q1) and `--cv-n-folds 3`, the natural layout is:
fold 0: train 2024-Q1..2024-Q4 (W=4) → val 2025-Q1
fold 1: train 2024-Q2..2025-Q1 → val 2025-Q2
fold 2: train 2024-Q3..2025-Q2 → val 2025-Q3
blind holdout: 2025-Q4, 2026-Q1
Threaded the flags through scripts/argo-alpha-perception.sh and
infra/k8s/argo/alpha-perception-template.yaml so each fold submits
as an independent workflow.
Updated tests/multi_horizon_loader.rs to the new API:
loader_yields_seq_with_valid_labels — exercises discover + load.
loader_errors_on_empty_files — replaces missing-root test.
discover_errors_on_missing_root — pinpoints the discover step.
Honors:
- feedback_no_partial_refactor.md — every consumer migrated atomically.
- feedback_no_legacy_aliases.md — no `mbp10_root` shim left behind.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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