---
pipeline_tag: image-text-to-text
---

# HAC: Parameter-Efficient Hyperbolic Adaptation of CLIP for Zero-Shot VQA

HAC (Hyperbolic Adaptation of CLIP) is a parameter-efficient framework that enables pretrained CLIP models to transition into hyperbolic space via lightweight fine-tuning. This approach captures hierarchical structures more effectively than traditional Euclidean embeddings, specifically for tasks like zero-shot Visual Question Answering (VQA).

This repository contains the weights for **HAC-B w/ LoRA**.

- **Paper:** [HAC: Parameter-Efficient Hyperbolic Adaptation of CLIP for Zero-Shot VQA](https://huggingface.co/papers/2604.23665)
- **GitHub Repository:** [https://github.com/fdibiton/HAC](https://github.com/fdibiton/HAC)

## Environment Setup

Create and configure the environment using Conda:

```bash
git clone https://github.com/fdibiton/HAC.git
cd HAC
conda create -n hac python=3.9 --yes
conda activate hac

# Install dependencies
python -m pip install --pre timm
python -m pip install -r requirements.txt
```

## Evaluation

To run zero-shot VQA evaluation with the HAC-B w/ LoRA model, place the `hac_vit_b_lora.pth` file in the `./checkpoints` directory and run:

```bash
python scripts/evaluate.py \
    --config configs/eval_vqa_all_categories.py \
    --train-config configs/train_hac_vit_b_lora.py \
    --checkpoint-path checkpoints/hac_vit_b_lora.pth
```

> **Note:** The VQA evaluation datasets need to be downloaded and arranged beforehand. Please refer to the instructions in the [GitHub repository](https://github.com/fdibiton/HAC) for details.

## Citation

```bibtex
@inproceedings{dibiton2026hac,
    title={HAC: Parameter-Efficient Hyperbolic Adaptation of CLIP for Zero-Shot VQA},
    author={Dibitonto, Francesco and Beyan, Cigdem and Murino, Vittorio},
    booktitle={International Conference on Pattern Recognition (ICPR)},
    year={2026}
}
```