TorchSparse

TorchSparse is a high-performance neural network library for point cloud processing.

Installation

TorchSparse depends on the Google Sparse Hash library.

• On Ubuntu, it can be installed by

  sudo apt-get install libsparsehash-dev

• On Mac OS, it can be installed by

  brew install google-sparsehash

• You can also compile the library locally (if you do not have the sudo permission) and add the library path to the environment variable

  CPLUS_INCLUDE_PATH

  .

The latest released TorchSparse (v1.4.0) can then be installed by

pip install --upgrade git+https://github.com/mit-han-lab/[email protected]

If you use TorchSparse in your code, please remember to specify the exact version in your dependencies.

For installation help and troubleshooting, please consult the Frequently Asked Questions before posting an issue.

Benchmark

We compare TorchSparse with MinkowskiEngine (where the latency is measured on NVIDIA GTX 1080Ti):

| | MinkowskiEngine v0.4.3 | TorchSparse v1.0.0 | | :----------------------- | :--------------------: | :----------------: | | MinkUNet18C (MACs / 10) | 224.7 ms | 124.3 ms | | MinkUNet18C (MACs / 4) | 244.3 ms | 160.9 ms | | MinkUNet18C (MACs / 2.5) | 269.6 ms | 214.3 ms | | MinkUNet18C | 323.5 ms | 294.0 ms |

Getting Started

Sparse Tensor

Sparse tensor (

SparseTensor

• Coordinates (

  coords

  ): a 2D integer tensor with a shape of N x 4, where the first three dimensions correspond to quantized x, y, z coordinates, and the last dimension denotes the batch index.
• Features (

  feats

  ): a 2D tensor with a shape of N x C, where C is the number of feature channels.

Most existing datasets provide raw point cloud data with float coordinates. We can use

sparse_quantize

torchsparse.utils.quantize

coords -= np.min(coords, axis=0, keepdims=True)
coords, indices = sparse_quantize(coords, voxel_size, return_index=True)
coords = torch.tensor(coords, dtype=torch.int)
feats = torch.tensor(feats[indices], dtype=torch.float)
tensor = SparseTensor(coords=coords, feats=feats)

We can then use

sparse_collate_fn

torchsparse.utils.collate

SparseTensor

coords

Sparse Neural Network

The neural network interface in TorchSparse is very similar to PyTorch:

from torch import nn
from torchsparse import nn as spnn

model = nn.Sequential(
    spnn.Conv3d(in_channels, out_channels, kernel_size),
    spnn.BatchNorm(out_channels),
    spnn.ReLU(True),
)

Citation

If you use TorchSparse in your research, please use the following BibTeX entry:

@inproceedings{tang2020searching,
  title = {{Searching Efficient 3D Architectures with Sparse Point-Voxel Convolution}},
  author = {Tang, Haotian and Liu, Zhijian and Zhao, Shengyu and Lin, Yujun and Lin, Ji and Wang, Hanrui and Han, Song},
  booktitle = {European Conference on Computer Vision (ECCV)},
  year = {2020}
}

Acknowledgements

TorchSparse is inspired by many existing open-source libraries, including (but not limited to) MinkowskiEngine, SECOND and SparseConvNet.