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Sunghoon Baek PRO

Baekpica

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updated a model 1 day ago
Baekpica/Inkling-2-Small-VQ-GGUF
updated a collection 2 days ago
DS4-VQ-for-DGX-Spark
posted an update 2 days ago
<Why I Released the Same DeepSeek-V4.1-Flash Variant Model Three Times> DeepSeek-V4.1-Flash-1017 is a 763B-parameter model with a 510 GB checkpoint. I compressed it into a 113.6 GB GGUF for a single 128 GB DGX Spark, retaining MTP, vision, and Engram components. But fitting the model and preserving its behavior turned out to be two different problems. 1. VQ — Making it fit I compressed 40 routed-expert layers using 8-dimensional vector quantization with 12/13-bit indices (1.5–1.625 index bits/weight). It fit, but minimizing weight reconstruction error didn’t necessarily preserve model outputs. 2. iVQ — Accounting for activations Inspired by llama.cpp’s importance matrix, I used 3.65M calibration tokens to make VQ activation-aware. Reconstruction improved, but end-to-end quality barely changed. A tiny fraction of extreme activations dominated the importance statistics, leaving typical tokens largely unaffected. 3. hVQ — Accounting for correlations I introduced Hessian-informed reconstruction with GPTQ-style error feedback to account for correlations between input channels. Surprisingly, plain weight error increased, while actual model fidelity improved: * Routed-expert output error: −34.5% * Generated-position KL: −17% * Top-1 agreement: 82.2% → 84.4% * Improvements across all 40 layers These gains were also reproduced in the actual GGUF serving engine on DGX Spark. 4. Inference optimization Further optimizations in ds4-dfm-rs improved median prefill throughput by 74% (955.5 → 1,662.2 tok/s across 2K–64K workloads). Decode runs at 30–36 tok/s with automatic MTP. The takeaway: Minimizing weight error, minimizing activation-weighted error, and preserving model behavior are fundamentally different optimization problems. At extreme compression ratios, understanding that difference matters more than simply reducing bits. https://huggingface.co/Baekpica/DeepSeek-V4.1-Flash-1017-hVQ-GGUF Runtime: https://github.com/Baekpica/ds4-dfm-rs
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