language:
- en
- ko
tags:
- speculative-decoding
- solar
license: other
license_name: solar-open2
license_link: LICENSE
Solar-Open2 250B + Speculative Draft (combined, 500K draft)
This repository bundles Upstage Solar Open2 250B-A15B (original weights at the
repository root, unchanged — see LICENSE and the tech report) together with our
block-draft speculative-decoding draft model in draft/.
- Root: Solar Open2 250B-A15B — 48 layers (12 NoPE GQA + 36 linear-attention), 320-expert MoE top-8, vocab 196,608. Original Upstage distribution files.
draft/: 5-layer draft (core 0.90B, total 2.51B with frozen target embedding/LM head), conditioned on five taps of the target's hidden states (layers 3/15/27/39/47). Proposes up to γ=7 tokens per step; the target verifies the block in one forward.
Draft results (500K-scale, 2 epochs)
| Metric | Value |
|---|---|
| val accept_len (γ=7) | 3.431 |
| Serving accept_len γ=3 / γ=7 | 2.75 / 3.54 |
| gsm8k (5-shot greedy, spec on) | 0.930–0.940 (lossless band) |
Training: 500K-scale multi-domain collection (415K-prompt manifest), ~1.2B tokens through the target for hidden-state distillation. 2 epochs, chunked KL, 2048 stratified anchors per batch.
Usage
Serve the root model as usual for non-speculative inference. For speculative
decoding, point your serving stack's block-draft speculative option at the
draft/ folder (block size 4–7 recommended, draft unquantized). Requires a
serving build with block-draft speculative decoding support for this draft
format.
License
Root model weights follow the Upstage Solar Open2 license (LICENSE). The
draft contains the target's frozen embedding/LM-head weights and follows the
same terms.