NVIDIA / NVIDIA/Model-Optimizer
[Bug] Qwen3-VL-30B-A3B NVFP4 quantization fails: hidden_size AttributeError in QuantQwen3VLMoeTextExperts
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Description
Environment
- nvidia-modelopt: 0.44.0 (latest PyPI + tested with latest source from main)
- TensorRT-Edge-LLM: 0.8.0
- Platform: NVIDIA Jetson AGX Thor (SM110, JetPack 7.2, CUDA 13.2)
- Model: Qwen/Qwen3-VL-30B-A3B-Instruct (HuggingFace)
- Python: 3.12
Problem
NVFP4 quantization of Qwen3-VL-30B-A3B-Instruct fails with a shape mismatch
in QuantQwen3VLMoeTextExperts during the MoE expert forward pass.
Error chain
- AttributeError: hidden_size in QuantQwen3VLMoeTextExperts
- mat1/mat2 shape mismatch in MoE expert forward
The error originates in modelopt's handling of this model's fused
gate_up_proj / refactored expert dimensions which do not match the
expected shapes in the MoE quantization code.
Steps to reproduce
tensorrt-edgellm-quantize-llm \
--model_dir ~/models/Qwen3-VL-30B-A3B-Instruct/ \
--output_dir ~/models/qwen3-vl-30b-nvfp4/onnx/ \
--quantization nvfp4
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the provided tensorrt-edgellm-quantize-llm command with Qwen/Qwen3-VL-30B-A3B-Instruct and NVFP4. Inspect QuantQwen3VLMoeTextExperts and the modelopt handling of fused gate_up_proj and refactored expert dimensions. Done means quantization completes without the hidden_size AttributeError or MoE expert shape mismatch.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python
- Domain
- machine-learning
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Needs clarification
- Newbie friendliness
- 42/100