5f196e3108
v_hack v2: top-k + S magnitudes + runtime suspicion gate + per-source cin
...
Extraction (extract_vhack_grad.py):
- Default top_k=12 (was 5), saves singular values S as _sv/{name} keys
- SVD orientation: majority-vote across pairs (was sign-of-mean, outlier-fragile)
- Pulled extract_v_hack() into a callable function for in-process reuse
- Fail-fast on non-finite NLL (would otherwise leave G_h/G_c length-mismatched)
Loading (train.py:load_v_hack):
- Returns (v_hack, v_sv) tuple; filters _sv/ keys into separate dict
- k_use slicing at load: extract at k=12, ablate k=1..12 by config flip
- Auto-extract on cache miss using already-wrapped model (no second model load)
- Default path derived from model_slug + extract_top_k
Runtime suspicion gate (proj.py:project_delta_S_grad):
- Dimensionless within-module ratio: r_i = (|c_i|/||g||) / (S_i/||S||)
(codex/subagent flagged: |c_i|/S_i biased by per-module ||g||)
- Per-step quantile gate drops top susp_drop_frac axes by r_i (default 0.25)
- Fail-fast if susp_drop_frac>0 and v_sv missing (old v1 file)
Per-source cin (proj.py:mean_cin_from_grads + train.py loss split):
- Per-prompt: backward student loss + teacher loss separately with retain_graph
- step_grad_s + step_grad_t = combined grad (linearity); used for projection
- cin_s, cin_t columns: discriminator for "does v_hack project hack > non-hack"
Doc: docs/extract_vhack_grad-vec.md (math, pseudocode, validation plan)
Codex external review: docs/spec/20260527_code_review.md
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com >
2026-05-27 06:39:05 +00:00
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