Qwen3.5-4BxOpus-4.6-Code-Reasoning-Full-Distilled-GGUF

A distilled, code-focused variant of Qwen3.5 4B, optimized for efficient local inference in GGUF format. This model targets coding, structured reasoning, and programmatic generation tasks, with optional reasoning traces via thinking mode.

---

Overview

• Distilled from Qwen3.5 (4B class)
• Optimized for llama.cpp inference
• Strong performance on code and reasoning tasks
• Supports extended context (practical range: 32K–64K)
• Compatible with Jinja chat templates
• Optional thinking mode (may increase latency)

---

Model Files

• Qwen3.5-4BxOpus-4.6-Code-Reasoning-Full-Distilled.Q4_K_M.gguf Quantized model (balanced size vs quality)

---

Example Usage

llama-cli -hf nphearum/Qwen3.5-4BxOpus-4.6-Code-Reasoning-Full-Distilled-GGUF --jinja

---

Running with llama.cpp

Ensure your build includes:

• Flash Attention
• Jinja/chat template support

---

Server Configuration (Optimized)

llama-server \
  -m Qwen3.5-4BxOpus-4.6-Code-Reasoning-Full-Distilled.Q4_K_M.gguf \
  --port 8001 \
  --alias qwen3.5-4b-opus \
  -c 65536 \
  -n 8192 \
  --no-context-shift \
  --temp 0.6 \
  --top-p 0.95 \
  --top-k 40 \
  --repeat-penalty 1.05 \
  --presence-penalty 0.0 \
  --flash-attn on \
  --fa on \
  --ctk q8_0 \
  --ctv q8_0 \
  --jinja \
  --chat-template-kwargs "{\"enable_thinking\": true}" \
  -ngl -1

---

Parameter Breakdown

Model Loading

• -m Loads the GGUF model file

• --alias Sets a simple API name

---

Context and Output

• -c 65536 Context window (recommended for 4B models)

• -n 8192 Maximum output tokens

• --no-context-shift Prevents automatic truncation of earlier tokens

---

Sampling Behavior

• --temp 0.6 Controls randomness

• --top-p 0.95 Nucleus sampling

• --top-k 40 Limits token candidates

• --repeat-penalty 1.05 Reduces repetition (important for code)

• --presence-penalty 0.0 No penalty for introducing new tokens

---

Performance and Memory

• -ngl -1 Full GPU offload

• --flash-attn on, --fa on Enables faster attention

• --ctk q8_0, --ctv q8_0 8-bit KV cache (reduces memory usage)

---

Chat and Reasoning

• --jinja Enables chat template rendering

• --chat-template-kwargs Enables thinking mode

Note: Thinking mode may:

• Improve reasoning quality
• Increase latency
• Produce unstable outputs if not aligned with training

---

Test Request

curl http://localhost:8001/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{
    "messages": [
      {"role": "user", "content": "Write a Python function to reverse a linked list"}
    ]
  }'

---

Recommended Configurations

Coding (deterministic)

--temp 0.4 --top-p 0.9 --top-k 50 --repeat-penalty 1.1

Reasoning (balanced)

--temp 0.6 --top-p 0.95 --top-k 40

Low VRAM

-c 32768 -n 4096 --flash-attn off -ngl 20

---

Limitations

• Quality degrades at extreme context lengths (>64K)
• Thinking mode increases latency
• Small models (4B) require tighter sampling tuning
• Performance depends heavily on GPU memory bandwidth

---

License

Follow the original Qwen license and any additional distillation terms.

---

Credits

• Base model: Qwen3.5
• Distillation: Code and reasoning optimization
• Runtime: llama.cpp ecosystem

---

Key Takeaway

This configuration is not a direct copy of larger models (e.g., 30B+). It is tuned specifically for a 4B model to balance:

• latency
• memory usage
• reasoning quality