pegasus-mini

PegasusLink mini (1.5B, distilled, GGUF)

A small, on-device chat model distilled from Qwen2.5-1.5B-Instruct and shipped as a q4 GGUF so it runs offline in llama.cpp / Ollama / a phone shell / the browser (WebGPU). It is the offline brain of the hybrid PegasusLink app at https://reverseml.online (online → cloud model + web search; offline → this).

Independent / solo project, open beta. Feedback and issues welcome.

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What is in this repo vs. what is in the app

Be clear about this, because they are different things:

• In this repo: the GGUF weights only — a fine-tuned 1.5B language model. That's it.
• In the app (NOT in the weights): the on-device cognitive stack — persistent Kalman attribute-memory, BM25+cosine hybrid RAG, device-to-device attribute merge, and an exact rational null-space chemistry balancer. Those live in the client (app-memory.js / app-chem.js) and wrap any local model; they are not baked into these weights. If you just load this GGUF in llama.cpp, you get the model, not the stack.

So: judge the GGUF here as a 1.5B chat model. The architecture writeup is on the site.

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How to run

llama.cpp

./llama-cli -m pegasus-mini-q4.gguf -p "Balance: H2 + O2 -> H2O" -ngl 99

Ollama

printf 'FROM ./pegasus-mini-q4.gguf\nPARAMETER temperature 0\nPARAMETER stop "<|im_end|>"\n' > Modelfile
ollama create pegasus-mini -f Modelfile
ollama run pegasus-mini "What is the pH of a neutral solution at 25 C?"

Phone: load the GGUF in a shell like ChatterUI. Browser: the WebLLM/WebGPU build (q4f16_1) is served from the site — zero install.

Prompt format is Qwen2 ChatML (<|im_start|> / <|im_end|>).

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Performance

Measured with Ollama, q4 GGUF, CPU-only (no GPU) on a 4-core AMD EPYC-Genoa VM:

That's CPU-only; on a laptop GPU or via WebGPU in the browser it's faster. The point is it's comfortably interactive on commodity hardware with no accelerator.

Example (temperature 0)

Prompt: Explain what a Kalman filter does in two sentences.

A Kalman filter is an algorithm that uses a combination of measurements and predictions to estimate the state of a system, such as a robot or an aircraft, by updating its estimates based on new information. It does this by using a mathematical model of the system to predict its future state, then comparing those predictions to actual measurements to refine them — it is widely used in robotics, navigation, and signal processing for estimating unknown variables under uncertainty.

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Training

• Base: Qwen2.5-1.5B-Instruct (Apache-2.0).
• Method: QLoRA, nightly, on a single A10G, merged → converted to GGUF (q4).
• Data (no raw private conversation):
  • seed instruction/QA pairs (incl. Wikipedia-derived factual QA);
  • execution-verified coding pairs (each solution is run in a locked-down sandbox against ground-truth tests; only passing ones are kept);
  • math solutions distilled from stronger peer models;
  • device-bridge pairs that are sanitized (emails/IPs/keys/tokens/long-digit runs scrubbed) and dropped if anything sensitive survives.
• Quality gate: before publishing, a fresh build must pass a coding/math/chemistry smoke gate; on failure it is not shipped. Nightly runs that see no new data skip training (no GPU spent).

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Intended use

General offline assistant for low-resource / private / edge settings: quick Q&A, coding help, math, deterministic chemistry balancing (via the app), and as a base to distill on your own data.

Out of scope / limitations

• It's 1.5B. Offline reasoning is modest — a capable local helper, not a frontier model. Verify anything important.
• On some mobile GPUs the driver watchdog (e.g. Adreno on recent Samsung devices) can drop the GPU context on larger kernels; the browser build is tuned around a ~1B stable ceiling with f16 and a reload-from-cache recovery loop.
• Autonomous/embedded use: the app has an experimental "device brain" for embedded/autonomous systems. It is an advisory, human-in-the-loop decision-support layer behind a safety license — NOT a certified autopilot. Do not wire a 1.5B model to actuate a real vehicle, drone, or machine as the sole controller. No warranty; you are responsible for legal compliance and any hardware you connect.

License & attribution

Released under Apache-2.0, inheriting from the Qwen2.5-1.5B-Instruct base. Please keep the Qwen attribution when redistributing. The weights are derived via distillation/ fine-tuning of that base.