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feat: add Vision Transformer (ViT) implementation for image classification - #13334

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cclauss merged 11 commits into
TheAlgorithms:masterfrom
devvratpathak:feat/vision-transformer
Sep 10, 2026
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feat: add Vision Transformer (ViT) implementation for image classification#13334
cclauss merged 11 commits into
TheAlgorithms:masterfrom
devvratpathak:feat/vision-transformer

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@devvratpathak

@devvratpathak devvratpathak commented Oct 7, 2025

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Describe your change:

This PR adds a comprehensive Vision Transformer (ViT) implementation to the computer_vision folder for image classification tasks, implementing the architecture from "An Image is Worth 16x16 Words: Transformers for Image Recognition at Scale" (Dosovitskiy et al., 2020).

The implementation includes patch embedding, positional encoding, attention mechanism, layer normalization, feed-forward network, transformer encoder blocks, and the complete ViT pipeline. All functions have comprehensive docstrings, type hints, doctests, and pass all ruff checks.

Fixes #13326

  • Add an algorithm?
  • Fix a bug or typo in an existing algorithm?
  • Add or change doctests? -- Note: Please avoid changing both code and tests in a single pull request.
  • Documentation change?

Checklist:

  • I have read CONTRIBUTING.md.
  • This pull request is all my own work -- I have not plagiarized.
  • I know that pull requests will not be merged if they fail the automated tests.
  • This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
  • All new Python files are placed inside an existing directory.
  • All filenames are in all lowercase characters with no spaces or dashes.
  • All functions and variable names follow Python naming conventions.
  • All function parameters and return values are annotated with Python type hints.
  • All functions have doctests that pass the automated testing.
  • All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
  • If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

…features section

- Add comprehensive table of contents for easy navigation
- Include detailed installation steps with virtual environment setup
- Add usage examples showing how to run and import algorithms
- Create features section listing all algorithm categories
- Add explicit license section with MIT License information
- Expand contributing section with quick start guide
- Add about section explaining repository purpose

Fixes TheAlgorithms#13111
…features section

- Add comprehensive table of contents for easy navigation
- Include detailed installation steps with virtual environment setup
- Add usage examples showing how to run and import algorithms
- Create features section listing all algorithm categories
- Add explicit license section with MIT License information
- Expand contributing section with quick start guide
- Add about section explaining repository purpose

Fixes TheAlgorithms#13111
…ation

- Implement complete ViT architecture with patch embedding
- Add positional encoding with learnable CLS token
- Include scaled dot-product attention mechanism
- Implement transformer encoder blocks with layer normalization
- Add feed-forward network with GELU activation
- Include comprehensive docstrings and type hints
- Add doctests for all functions
- Provide example usage demonstrating the complete pipeline

Fixes TheAlgorithms#13326
- Replace Optional with X | None syntax (UP045)
- Use np.random.Generator instead of legacy np.random methods (NPY002)
- Fix line length violations (E501)
- Assign f-string literals to variables in exceptions (EM102)
- Remove unused variables and parameters (RUF059, F841)
- Add noqa comment for intentionally unused API parameter
- All doctests still pass successfully
@algorithms-keeper algorithms-keeper Bot added documentation This PR modified documentation files require descriptive names This PR needs descriptive function and/or variable names labels Oct 7, 2025

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Click here to look at the relevant links ⬇️

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Comment thread computer_vision/vision_transformer.py Outdated
return output, attention_weights


def layer_norm(x: np.ndarray, epsilon: float = 1e-6) -> np.ndarray:

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Please provide descriptive name for the parameter: x

Comment thread computer_vision/vision_transformer.py Outdated
return (x - mean) / (std + epsilon)


def feedforward_network(x: np.ndarray, hidden_dim: int = 3072) -> np.ndarray:

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Please provide descriptive name for the parameter: x

Comment thread computer_vision/vision_transformer.py Outdated


def transformer_encoder_block(
x: np.ndarray, num_heads: int = 12, hidden_dim: int = 3072 # noqa: ARG001

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Please provide descriptive name for the parameter: x

@algorithms-keeper algorithms-keeper Bot added the awaiting reviews This PR is ready to be reviewed label Oct 7, 2025
- Rename 'x' to 'embeddings' in layer_norm, feedforward_network,
  and transformer_encoder_block functions
- Update all docstring examples to use 'embeddings'
- Improves code readability per algorithms-keeper bot feedback
- Fix noqa comment placement for unused num_heads parameter
- All doctests and ruff checks pass
@devvratpathak devvratpathak reopened this Oct 7, 2025
@algorithms-keeper algorithms-keeper Bot removed the require descriptive names This PR needs descriptive function and/or variable names label Oct 7, 2025
@github-actions
github-actions Bot force-pushed the feat/vision-transformer branch from 95afd01 to c9f02a6 Compare September 10, 2026 16:55
@github-actions
github-actions Bot force-pushed the feat/vision-transformer branch from c9f02a6 to c0911f5 Compare September 10, 2026 16:55
Removed sections on Table of Contents, About, Features, and Contributing from README.
@algorithms-keeper algorithms-keeper Bot removed the awaiting reviews This PR is ready to be reviewed label Sep 10, 2026
@cclauss
cclauss merged commit 2e96671 into TheAlgorithms:master Sep 10, 2026
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Add Vision Transformer code for image classification

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