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README.md

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 # SpTr: PyTorch Spatially Sparse Transformer Library
 
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 **SparseTransformer (SpTr)** provides a **fast**, **memory-efficient**, and **easy-to-use** implementation for sparse transformer with **varying token numbers** (e.g., window transformer for 3D point cloud).
 
 **SpTr** has been used by the following works: