RESULT 22 arms7 verdict (centered@3e-3 wins tail-SNR, momentum refuted) + RESULT 23 gap-scaling pre-registration; ladder launched GPU1+GPU3

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014FAPDWQ49M5Ye3NpTndTpn

1 files changed, 51 insertions, 0 deletions

diff --git a/docs/campaign/CASCADE_ABLATION_PLAN.md b/docs/campaign/CASCADE_ABLATION_PLAN.md
index d59a47d..8e9faf3 100644
--- a/docs/campaign/CASCADE_ABLATION_PLAN.md
+++ b/docs/campaign/CASCADE_ABLATION_PLAN.md
@@ -568,6 +568,57 @@ direction), not training-under-fault; wave-2 = co-training with faults injected
 
 
 
+### RESULT 23 (2026-07-14): GAP-SCALING SUITE — PRE-REGISTRATION (launched, results pending).
+Question: how does the EP-BP epoch gap scale with model width under the FROZEN stage1b recipe?
+Design: C ∈ {128, 192, 256, 384} x L12 H8 T256 B24, tinystories_bpe, full data-matched epoch
+(58800 steps — identical token stream for every size), EP = frozen stage1b recipe + --amp
+(lr 1e-3, beta 3e-3, K3, floor 3e-4, bf_late 1e-3@15k, kretry 8, olmo2, wd 0.1, muon, cosine,
+warmup 500, seed 1); BP twin = casc_bp_train.py mirrored flags + --amp. Anchor points already
+measured: C512 = 1.2808 vs 1.2311 (gap 0.050); fw72m (different data) 3.71 vs 3.29.
+Runs: gs_ep_c{128,192,256,384} + gs_bp_c{...}, wandb project ept-tinystories-gapscaling.
+PRE-REGISTERED PREDICTIONS (before any result):
+- H-A (user hypothesis): bigger = more robust to update noise -> gap DECREASES with C.
+- H-B (loop-gain): wall-2 gain grows with sigma*||J|| chains -> gap INCREASES with C at frozen beta;
+  expected WEAK below 42M (window still wide — zero skips at C512).
+- H-C (detune): recipe tuned at C512 -> smallest C off-tuned -> gap inflated at C128 for
+  uninteresting reasons.
+- Registered call: mild H-A trend, gap(C128) ~= 0.06-0.10 falling to 0.050 at C512, possible C128
+  outlier from H-C. Falsifier that matters: monotone INCREASING gap -> H-B active even sub-42M ->
+  per-size beta recalibration becomes mandatory before any scaling claim.
+- Noise floor: seed band ~±0.006 (amp 3-seed); single seed per size -> differences <0.01 are NOT
+  interpretable; if the trend lands inside the band, extremes get 3 seeds before any conclusion.
+
+### RESULT 22 (2026-07-14): TAIL-SNR SEVEN ARMS — centered estimator at BIG beta WINS; momentum-on-ghat REFUTED.
+Setup: resume stage1b_ep_muon_s45000.pt, run 45k->55k (10k tail steps, the low-|g| regime where
+wall-1 bites), all --amp, common recipe; one knob per arm. Reference: original run at s55000 = 1.2808
+(fp32; data order differs after resume, so judge arms vs arm_ctl, not vs 1.2808).
+| arm | tail beta | knob | best val CE | last gate cos | verdict |
+|---|---|---|---|---|---|
+| arm_ctl | 1e-3 flat | none (muon .95) | 1.2678 | 0.994 | baseline |
+| arm_cent_f3e3 | 3e-3 flat | --est centered | **1.2591** | **0.997** | **WINNER (-0.009)** |
+| arm_adamw_f1e3 | 1e-3 flat | --opt adamw | 1.2664 | 0.994 | tie (-0.001) |
+| arm_rich_f1e3 | 1e-3 flat | --est richardson | 1.2830 | 0.986 | LOSES (+0.015) |
+| arm_mom99_f1e3 | 1e-3 flat | muon_mom 0.99 | 1.2867 | 0.994 | LOSES (+0.019) |
+| arm_mom99_f3e4 | 3e-4 flat | mom 0.99, beta/3 | 1.3266 | 0.993 | LOSES (+0.059) |
+| arm_mom995_f1e4 | 1e-4 flat | mom 0.995, beta/10 | 1.3440 | 0.973 | LOSES (+0.076) |
+Readings:
+- CENTERED at 3x beta wins BOTH CE and cos: O(beta^2) bias lets beta ride high -> readout noise
+  /3 -> SNR up. Cost: 2 nudged phases, measured ~1.8x step time (15.1 -> 8.2 it/s). THE key that
+  opens the wall-1 tail lock.
+- MOMENTUM-on-ghat REFUTED in all three doses: at matched beta it loses 0.019; using momentum to
+  BUY lower beta (the sqrt-N averaging idea) loses monotonically more (0.059, 0.076). The noise
+  is not zero-mean-averageable at the update level the way the hypothesis needed (Muon
+  orthogonalization + staleness at decaying LR).
+- Richardson loses at matched beta: the 2g(b)-g(2b) combination amplifies variance ~sqrt(5)x —
+  strictly dominated by centered-at-big-beta.
+- AdamW == Muon at the tail (1.2664 vs 1.2678): the NS-orthogonalization noise-amplification
+  suspicion is NOT confirmed; no reason to switch (Muon carried the 0.050 epoch gap).
+- ctl at FLAT 1e-3 (1.2678) beats the original decaying schedule at s55000 (1.2808): more evidence
+  the tail wants BIGGER beta, not smaller — consistent with the rising SNR floor picture.
+- CROWN-RERUN NOTE (72M and up): wall-2 caps beta from ABOVE there, so "centered + big beta" must
+  become "centered + beta pinned at the bcap ceiling" — bias falls to O(beta^2) at unchanged loop
+  gain. Momentum is off the table; bcap-v3 (attack threshold ~0.92) remains the other half.
+
 ### RESULT 21 (2026-07-14): CROWN SEALED — 72.11M x 1.44B tokens, fully BP-free, largest to date.
 fw72m_c2 reached 234,000 steps = the full Chinchilla budget (segments: 0-195k original schedule +
 195-215k blow-recipe + 215-234k bcap-v2; final segment skips=1, drift 0.016 — the wall managed).