Documentation

This package consists of a small extension library of highly optimized sparse update (scatter) operations for the use in PyTorch, which are missing in the main package. Scatter operations can be roughly described as reduce operations based on a given "group-index" tensor. The package consists of the following operations:

• Scatter Add
• Scatter Sub
• Scatter Mul
• Scatter Div
• Scatter Mean
• Scatter Std
• Scatter Min
• Scatter Max

All included operations work on varying data types, are implemented both for CPU and GPU and include a backwards implementation.

Ensure that at least PyTorch 1.0.0 is installed and verify that cuda/bin and cuda/include are in your $PATH and $CPATH respectively, e.g.:

$ python -c "import torch; print(torch.__version__)"
>>> 1.0.0

$ echo $PATH
>>> /usr/local/cuda/bin:...

$ echo $CPATH
>>> /usr/local/cuda/include:...

Then run:

pip install torch-scatter

If you are running into any installation problems, please create an issue. Be sure to import torch first before using this package to resolve symbols the dynamic linker must see.

import torch
from torch_scatter import scatter_max

src = torch.tensor([[2, 0, 1, 4, 3], [0, 2, 1, 3, 4]])
index = torch.tensor([[4, 5, 4, 2, 3], [0, 0, 2, 2, 1]])

out, argmax = scatter_max(src, index)

print(out)
tensor([[ 0,  0,  4,  3,  2,  0],
        [ 2,  4,  3,  0,  0,  0]])

print(argmax)
tensor([[-1, -1,  3,  4,  0,  1]
        [ 1,  4,  3, -1, -1, -1]])

python setup.py test