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Vit Explain

Vit Explain is a Python library that calculates Attention Rollout and class-specific Gradient Attention Rollout for Vision Transformers, producing masks to visualize image regions associated with model attention and a target-class output.

Independent OpenViST project profile, based on linked sources.

Vit Explain — OpenViST project profile in AI Evaluation & Observability.
OpenViST project illustration. See the linked sources for product details.
Understand the project

Practical overview

When it fits

Use Vit Explain when you have a Vision Transformer and want an attention-based visual aid for inspecting image regions, especially when comparing general attention with a target-class explanation.

Who it is for

  • Developers building PyTorch image-classification tools who want to show attention visualizations.
  • Practitioners inspecting Vision Transformer behavior during model debugging.
  • Researchers comparing attention-head fusion or filtering settings.

Documented uses

  • Generate a general attention mask for an image.
  • Inspect attention associated with a selected class using a category index.
  • Compare mean, minimum and maximum attention-head fusion, or filter weaker attention values.
Before you choose

Requirements & limits

The repository is public and identifies its license as MIT. The README lists `timm` as a requirement.

  • Omitting a category index selects Attention Rollout; supplying one selects class-specific Gradient Attention Rollout.
  • Head fusion can be set to mean, minimum or maximum, and the discard ratio controls filtering of weaker attention values.
  • The included example uses DeiT Tiny loaded through PyTorch Hub; other model implementations may require modification.
  • The masks are inspection aids and should not be read as proof that a highlighted region caused the model’s classification.

Check current requirements in the official documentation. Source-based guidance does not mean OpenViST has run or independently tested this project.

Source-based practical guide

Generate an attention mask from the command line

Use the documented command-line interface to request an attention rollout for an image.

Before you start

  • The Vit Explain repository and its Python command-line script.
  • An image file and a category index if class-specific Gradient Attention Rollout is wanted.
  • The README lists timm as a requirement.

Steps

  1. Run the command below with --image_path set to the image file.

    Documented command
    python vit_explain.py
  2. Choose --head_fusion as mean, min or max and set --discard_ratio to a value between 0 and 1.

  3. Add --category_index to request Gradient Attention Rollout for a target category; omit it to use Attention Rollout.

Expected outcome

The command requests an attention visualization for the supplied image, using the chosen fusion and filtering settings.

Guide limitations

  • The documentation describes the command and its options but does not specify output-file handling.
  • A category index is required for the class-specific method; the documentation does not establish compatibility with models beyond its demonstrated DeiT example.
Source-based practical guide

Set up the documented DeiT example in Python

Load the demonstrated DeiT Tiny model and prepare a class-specific gradient-rollout call.

Before you start

  • Python with PyTorch and the timm package listed by the README.
  • The project’s vit_grad_rollout module.

Steps

  1. Load deit_tiny_patch16_224 with torch.hub.load('facebookresearch/deit:main', 'deit_tiny_patch16_224', pretrained=True).

  2. Create VITAttentionGradRollout with the model, a discard_ratio and a head_fusion setting.

  3. Pass an input tensor and a target category_index to the rollout object.

Expected outcome

The documented call returns a mask for the chosen category and input tensor.

Guide limitations

  • The README demonstrates DeiT Tiny; support for other Vision Transformer implementations is not established.
  • The example assumes an input_tensor is available but does not document image preprocessing.
Evidence and transparency

Sources & review

Source record details
Source availability
Active
Sources checked
4 November 2026
Original website title
jacobgil/vit-explain · Official homepage title · retained in its source language