decompute/Nebula-S-v1

TEXT GENERATIONConcurrency Cost:1Model Size:4BQuant:BF16Ctx Length:32kPublished:Apr 15, 2026License:apache-2.0Architecture:Transformer0.0K Open Weights Cold

decompute/Nebula-S-v1 is a 4-billion parameter language model developed by decompute, featuring a Structured-Vector Multi-Stream (SVMS) architecture. This model integrates a multi-stream reasoning layer on top of a frozen backbone, enhancing its capabilities in complex reasoning tasks. With a 32768-token context length, Nebula-S-v1 demonstrates strong performance on mathematical reasoning and advanced knowledge benchmarks like GSM8K and MMLU-Pro.

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Nebula-S-v1: Reasoning-Enhanced Language Model

Nebula-S-v1 is a 4-billion parameter language model developed by decompute, distinguished by its Structured-Vector Multi-Stream (SVMS) architecture. This innovative design incorporates a multi-stream reasoning layer over a frozen 4B-parameter backbone, with only 400 million parameters being trainable. The SVMS architecture includes structured consistency for cross-stream coherence, a learned router for per-token stream weighting, and delta logits for prediction correction.

Key Capabilities & Performance

Nebula-S-v1 was specifically trained on 200,000 Orca Math Word Problems using an adapter-only method, focusing on enhancing its reasoning abilities. Evaluation results highlight its strong performance, particularly in areas requiring logical deduction and advanced knowledge:

  • GSM8K: Achieved 90% accuracy, indicating robust mathematical reasoning.
  • GPQA: Scored 70.5%.
  • HMMT (November 2025): Reached 67%.
  • MMLU-Pro: Demonstrated 79.7% performance.

These scores underscore its effectiveness in complex problem-solving and competitive-level tasks, making it a powerful tool for applications requiring precise and structured reasoning.

Good For

  • Mathematical Reasoning: Excels in solving math word problems and similar quantitative tasks.
  • Complex Problem Solving: Suitable for applications requiring advanced logical deduction and structured thinking.
  • Knowledge-Intensive Tasks: Performs well on benchmarks assessing broad knowledge and understanding.