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Record: Seed-Regenerated Random Model + Incremental N-gram Cache — val_bpb 0.0905#1095

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Record: Seed-Regenerated Random Model + Incremental N-gram Cache — val_bpb 0.0905#1095
vimeto wants to merge 1 commit intoopenai:mainfrom
vimeto:pr/seed-regen-ngram

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@vimeto vimeto commented Mar 29, 2026

Record: Seed-Regenerated Random Model + Incremental N-gram Cache — val_bpb 0.0905

val_bpb = 0.0905 (1 seed, additional seeds pending H100 access) | 15.09 MB | 8xH100 SXM

Results (8xH100 80GB SXM, PyTorch 2.7.1)

Seed step_avg steps neural_bpb blended_bpb Artifact
1337 60ms 9,912 1.503 0.0905 15,093,968
42 pending
2025 pending

Additional seeds pending H100 access.

Key Innovation: Zero-Cost Base Weights

ALL transformer weight matrices use frozen orthogonal random projections regenerated from 8-byte seeds at load time (0 bytes in artifact). Only rank-64 LoRA adapters are stored (3.9 MB). The remaining 11 MB holds an incrementally-built INT16 n-gram cache (orders 2-7, 31B counts, 8-GPU all-reduce synced).

Why orthogonal: Prior work (PR #874) used Gaussian random bases but could not train past 5 layers. Our QR-decomposed orthogonal init preserves singular values = 1.0, enabling stable deep training.

Adapter quantization: Simple INT8 per-row gives quant gap of only +0.003 BPB (vs +0.006 for baseline INT6 GPTQ).

Incremental N-gram Cache (Zero Overhead)

The cache is built during training by calling update_batch_fast() after each microstep (less than 1ms overhead). After training, counts are all-reduced across 8 GPUs and LZMA-compressed into the artifact. At eval, the cache is frozen, no TTT.

We tested pre-filling from training shards at startup: 10x worse (0.996 BPB) due to pre-fill consuming 24-33% of the training budget.

Architecture

5L 512d, 8H/4KV, MLP 3.0, LeakyReLU(0.5) squared, rank-64 LoRA adapters, tied embeddings, vocab 1024

Credits

@vimeto vimeto force-pushed the pr/seed-regen-ngram branch from 776a620 to 38c5e7d Compare March 29, 2026 20:44
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