MolmoAct-7B-D AWQ 4-bit (Text-Only Quantization)

This is a 4-bit AWQ quantized version of allenai/MolmoAct-7B-D-0812 using LLM Compressor.

Key Features

  • Qwen2.5 text decoder quantized (4-bit AWQ) - 63% size reduction
  • SigLip2 vision encoder preserved (FP16) - maintains visual quality
  • Robotic manipulation action reasoning - trained on 10k robot trajectories
  • Smart quantization - Only LLM layers quantized, vision parts untouched
  • 93 unique manipulation tasks supported

Model Details

  • Base Model: allenai/MolmoAct-7B-D-0812 (7B parameters)
  • Architecture: MolmoAct (Qwen2.5-7B decoder + SigLip2 vision encoder)
  • Quantization Method: AWQ (Activation-aware Weight Quantization)
  • Quantization Scheme: W4A16 (4-bit weights, 16-bit activations)
  • Calibration Dataset: Flickr30k (512 samples)

Size Comparison

Metric Value
Original (FP16) ~14.0 GB
Quantized (W4A16) ~6.12 GB
Reduction ~56.3%
Memory Saved ~7.9 GB

What Was Quantized

Quantized (4-bit):

  • Qwen2.5 decoder layers (text/language model)
  • Text processing linear layers in the decoder

Preserved (FP16):

  • SigLip2 vision encoder (maintains visual understanding quality)
  • Vision-text connectors
  • Embeddings
  • Language model head

This selective quantization ensures that vision understanding quality remains nearly identical to the original model while significantly reducing size.

About MolmoAct-7B-D

MolmoAct-7B-D is an open-source action reasoning model for robotic manipulation developed by the Allen Institute for AI:

  • Training Data: 10k high-quality trajectories of a single-arm Franka robot
  • Text Decoder: Qwen2.5-7B (state-of-the-art open LLM)
  • Vision Encoder: SigLip2 (proven vision backbone)
  • Capabilities: 93 unique manipulation tasks
  • Use Case: Robotic manipulation and action reasoning

Usage

from transformers import AutoModelForImageTextToText, AutoProcessor, GenerationConfig
from PIL import Image
import requests

# Load model and processor
processor = AutoProcessor.from_pretrained(
    "ronantakizawa/molmoact-7b-d-awq-w4a16",
    trust_remote_code=True,
    torch_dtype='auto',
    device_map='auto'
)

model = AutoModelForCausalLM.from_pretrained(
    "ronantakizawa/molmoact-7b-d-awq-w4a16",
    trust_remote_code=True,
    torch_dtype='auto',
    device_map='auto'
)

# Process the image and text
inputs = processor.process(
    images=[Image.open(requests.get("https://picsum.photos/id/237/536/354", stream=True).raw)],
    text="What actions can be performed with the objects in this image?"
)

# Move inputs to the correct device and make a batch of size 1
inputs = {k: v.to(model.device).unsqueeze(0) for k, v in inputs.items()}

# Generate output
output = model.generate_from_batch(
    inputs,
    GenerationConfig(max_new_tokens=200, stop_strings="<|endoftext|>"),
    tokenizer=processor.tokenizer
)

# Decode the generated tokens
generated_tokens = output[0, inputs['input_ids'].size(1):]
generated_text = processor.tokenizer.decode(generated_tokens, skip_special_tokens=True)
print(generated_text)

Quantization Details

  • Method: AWQ (Activation-aware Weight Quantization)
  • Independent Pipeline: Used with BasicPipeline for layer-by-layer quantization
  • Calibration: 512 Flickr30k image-text pairs
  • Max Sequence Length: 2048 tokens
  • Why AWQ: Activation-aware quantization preserves important weights

Limitations

  • May have slight quality degradation in complex action reasoning compared to FP16
  • Vision encoder is NOT quantized (intentional for quality)
  • Requires transformers with AWQ support
  • Designed for robotic manipulation tasks, not general conversation

Important Notes

Image Requirements

Ensure images are in RGB format:

from PIL import Image
image = Image.open(...)
if image.mode != "RGB":
    image = image.convert("RGB")

License

Apache 2.0 (same as base model)

Citation

@misc{molmoact-7b-d-awq,
  title={MolmoAct-7B-D AWQ 4-bit},
  author={Quantized by ronantakizawa},
  year={2025},
  url={https://huggingface.co/ronantakizawa/molmoact-7b-d-awq-w4a16}
}

Acknowledgements


🤖 Generated with LLM Compressor

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