opt: cumsum/chunked attention kernels, memory-flat CE, block checkpointing, v2 trainer (proven equivalent, 46 tests)

docs/NEXT_TRAINING_CHECKLIST.md

@@ -13,4 +13,20 @@
 7. Smoke: log omega std, expert load entropy; confirm TF still drops.
 8. Hourly HF push of 8 ckpts + merge.
 
+## Optimized relaunch (fractus-opt, 2026-08-24)
+
+After the Kuramoto fix, swap in the proven-equivalent optimized path
+(repo **AFKmoney/fractus-opt**, guide: its `docs/OPTIMIZATION_2026-08-22.md` §3):
+
+1. Replace `fractus/nn/attention.py`, add `fractus/nn/ce.py`,
+   replace `fractus/continuous_engine.py`, use `scripts/fast4gpu_boost_v2.py`.
+2. First relaunch with v1 settings (`BATCH=4 CE_CHUNK=0`) → ema_tf must
+   continue its curve exactly (real-conditions equivalence check).
+3. Escalate: `CE_CHUNK=2048` → `FRACTUS_ATTN_IMPL=chunked` → `COMPILE=1`
+   + raise `BATCH`. Validate tok/s + VRAM at each step; read live tok/s
+   from stdout to update the time-to-finish table in
+   `HOW_FRACTUS_IS_TRAINED.md` §8.
+4. Budget: one full phase-2 pass ≈ 425–430M tok/GPU remaining →
+   **4.5–5.5 days at baseline rate** (see HOW_FRACTUS_IS_TRAINED.md §8).
+
 See `docs/KURAMOTO_BOTTLENECK_AND_FIX.md` and `docs/HOW_FRACTUS_IS_TRAINED.md`.