How to use from the
Use from the
llama-cpp-python library
# !pip install llama-cpp-python

from llama_cpp import Llama

llm = Llama.from_pretrained(
	repo_id="XpressAI/Qwen3.5-2B-RYS-UD-Q4_K_XL-GGUF",
	filename="",
)
llm.create_chat_completion(
	messages = "No input example has been defined for this model task."
)

Qwen3.5-2B โ€” RYS Layer Surgery (GGUF)

Two modified versions of Qwen3.5-2B-Instruct produced by RYS layer duplication โ€” no training, no weight changes, just routing hidden states through a specific circuit twice.

Based on David Ng's RYS method.


Files

File Layers Size
Qwen3.5-2B-UD-Q4_K_XL.gguf 24 1.34 GiB
Qwen3.5-2B-rys_8-11-UD-Q4_K_XL.gguf 28 1.39 GiB
Qwen3.5-2B-rys_7-10_reasoning-UD-Q4_K_XL.gguf 28 1.38 GiB

Probe scores

Scores from an internal sweep benchmark run during circuit search. Sample sizes are small โ€” treat these as directional indicators, not definitive benchmarks.

Model Math EQ Reasoning
Base (24 layers) 0.188 0.0 0.118
rys_8-11 (28 layers) 0.125 11.3 0.176
rys_7-10_reasoning (28 layers) 0.062 0.0 0.294
  • Math: Ng's partial-credit scoring on a small GSM8K sample
  • EQ: EQ-Bench-style emotional intelligence score (0โ€“100)
  • Reasoning: fraction correct across causal, date, logic, navigation, and GSM8K probes

rys_8-11 shows the best combined improvement: EQ rises from 0 to 11.3 and reasoning improves. rys_7-10_reasoning achieves the highest reasoning score (0.294 vs 0.118 baseline) but at the cost of math and EQ.


What is RYS?

Transformers self-organise during training into functional circuits โ€” contiguous blocks of layers that act together. The RYS technique duplicates a specific block in the forward pass using the same weights, with no extra copies on disk beyond the GGUF file overhead:

Normal:  0 โ†’ โ€ฆ โ†’ 7 โ†’ 8 โ†’ 9 โ†’ 10 โ†’ 11 โ†’ 12 โ†’ โ€ฆ โ†’ 23
rys_8-11: 0 โ†’ โ€ฆ โ†’ 7 โ†’ 8 โ†’ 9 โ†’ 10 โ†’ 11
                      โ†’ 8 โ†’ 9 โ†’ 10 โ†’ 11 โ†’ 12 โ†’ โ€ฆ โ†’ 23

The model processes the circuit twice, without any weight changes or fine-tuning.


Hybrid Mamba/attention architecture constraint

Qwen3.5-2B is a hybrid SSM/attention model (full_attention_interval = 4): full attention every 4th layer, Gated DeltaNet SSM everywhere else. The architecture repeats 6 times:

3 ร— (DeltaNet โ†’ FFN) โ†’ 1 ร— (Attention โ†’ FFN)

This creates a hard constraint on layer surgery: the total layer count must remain divisible by 4.

  • Block size 4 โ†’ 24 + 4 = 28 layers (28 รท 4 = 7 โœ“)
  • Block size 8 โ†’ 24 + 8 = 32 layers (32 รท 4 = 8 โœ“)
  • Block size 3 โ†’ 24 + 3 = 27 layers (27 รท 4 = 6.75 โœ— โ†’ crash)

rys_8-11 duplicates layers 8โ€“11, one complete DeltaNet+Attention unit. rys_7-10_reasoning duplicates layers 7โ€“10, spanning the boundary between two attention intervals.


How the circuit was found

A two-pass sweep over the 24-layer model:

Pass 1 โ€” 8-layer blocks, stride 4, layers 0โ€“16:

  • (4, 12) identified as the hot zone: EQ=11.76, reasoning=0.176

Pass 2 โ€” 4-layer blocks, stride 1, layers 4โ€“16:

  • (8, 12) best combined: EQ=11.33, reasoning=0.176
  • (7, 11) best reasoning: reasoning=0.294

Each configuration was tested by patching the GGUF layer path, loading with llama-server, and scoring with the probe suite.


Usage

llama.cpp / llama-server

# Best combined (EQ + reasoning)
llama-server -m Qwen3.5-2B-rys_8-11-UD-Q4_K_XL.gguf -ngl 99 --port 8080

# Best reasoning
llama-server -m Qwen3.5-2B-rys_7-10_reasoning-UD-Q4_K_XL.gguf -ngl 99 --port 8080

Thinking mode

Qwen3.5 defaults to thinking mode (<think>โ€ฆ</think>). Add /no_think to the system prompt for fast, direct answers:

messages = [
    {"role": "system", "content": "/no_think"},
    {"role": "user",   "content": "Your question here"}
]

VRAM requirements

Model weights are ~1.4 GiB (Q4_K_XL, 28 layers). Runs on any modern GPU or CPU.


Credits

License

Apache 2.0 (inherited from base model)

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