Record: 10L Mixed Precision: val_bpb=1.2147 (10 layers + int6 middle layers) (#39)

* Add Lower LR submission: val_bpb=1.2230 (MATRIX_LR=0.02)

Systematic LR sweep showed default Muon/Adam learning rates (0.04) were
too high. MATRIX_LR=0.02, SCALAR_LR=0.02, TIED_EMBED_LR=0.03 gives
consistent improvement. Same 9L/512d architecture, no other changes.

* Add 10L Mixed Precision submission: val_bpb=1.2147

10 transformer layers (vs baseline 9) with mixed int8/int6 compression:
- Full int8 for first/last 3 layers (precision-sensitive)
- Int6 (step=4 rounding) for middle layers 3-6 (compression-friendly)
- Lower LR: MATRIX_LR=0.02, SCALAR_LR=0.02, TIED_EMBED_LR=0.03
- Artifact: 15,928,974 bytes (under 16MB cap)
- Improvement: 0.0097 bpb / 0.0217 nats over baseline (1.2244)

Also adds PRUNE_RATIO and INT4_LAYERS/INT4_STEP support to train_gpt.py
for mixed-precision post-training quantization.

* Revert root train_gpt.py to upstream baseline

The root script should remain the baseline. Submission-specific
modifications (PRUNE_RATIO, INT4_LAYERS, INT4_STEP) only belong
in the records/ folder copy.

1 files changed, 11 insertions, 0 deletions

diff --git a/records/track_10min_16mb/2026-03-18_LowerLR/submission.json b/records/track_10min_16mb/2026-03-18_LowerLR/submission.json
new file mode 100644
index 0000000..42ec327
--- /dev/null
+++ b/records/track_10min_16mb/2026-03-18_LowerLR/submission.json
@@ -0,0 +1,11 @@
+{
+  "author": "Nan Liu",
+  "github_id": "nanlliu",
+  "name": "Lower LR",
+  "blurb": "Same 9x512 SP-1024 KV4 tied-embedding baseline architecture with lower Muon/Adam learning rates (MATRIX_LR=0.02, SCALAR_LR=0.02, TIED_EMBED_LR=0.03). Systematic LR sweep showed default 0.04 was too high; optimal is ~0.02.",
+  "date": "2026-03-18T22:30:00Z",
+  "val_loss": 2.06492760,
+  "val_bpb": 1.22296644,
+  "bytes_total": 15854246,
+  "bytes_code": 50919
+}