python pytorch fft_PyScatWave 用CuPy / PyTorch快速散射变换

Announcement

11/18

This package is no longer supported. We have now released kymatio: http://www.kymat.io/ , https://github.com/kymatio/kymatio which includes 1D-2D-3D fast, optimized, differentiable Scattering Transform and subsumes all the behavior of pyscatwave. Among other things you can now more easily use differentiable 2d scattering and use the CPU if desired. kymatio will be well supported with a substantially larger development team than pyscatwave.

07/18

We just released a differentiable 2D Scattering example in the master. It is not memory efficient yet, neither fast.

PyScatWave

CuPy/PyTorch Scattering implementation

A scattering network is a Convolutional Network with filters predefined to be wavelets that are not learned and it can be used in vision task such as classification of images. The scattering transform can drastically reduce the spatial resolution of the input (e.g. 224x224->14x14) with demonstrably neglible loss in dicriminative power.

The software uses PyTorch + NumPy FFT on CPU, and PyTorch + CuPy + CuFFT on GPU.

Previous (lua-based) versions of the code can be found at https://github.com/edouardoyallon/scatwave

If using this code for your research please cite our paper:

You can find experiments from the paper in the following repository: https://github.com/edouardoyallon/scalingscattering/

We used PyTorch for running experiments in https://arxiv.org/abs/1703.08961, but it is possible to use scattering with other frameworks (e.g. Chainer, Theano or Tensorflow) if one copies Scattering outputs to CPU (or run on CPU and convert to numpy.ndarray via .numpy()).

Benchmarks

We do some simple timings and comparisons to the previous (multi-core CPU) implementation of scattering (ScatnetLight). We benchmark the software using a 1080 GPU. Below we show input sizes (WxHx3xBatchSize) and speed:

32 × 32 × 3 × 128 (J=2)- 0.03s (speed of 8x vs ScatNetLight)

256 × 256 × 3 × 128 (J=2) - 0.71 s (speed up of 225x vs ScatNetLight)

Installation

The software was tested on Linux with anaconda Python 2.7 and various GPUs, including Titan X, 1080s, 980s, K20s, and Titan X Pascal.

The first step is to install pytorch following instructions from http://pytorch.org, then you can run pip:

pip install -r requirements.txt

python setup.py install

Usage

Example:

import torch

from scatwave.scattering import Scattering

scat = Scattering(M=32, N=32, J=2).cuda()

x = torch.randn(1, 3, 32, 32).cuda()

print scat(x).size()

Contribution

All contributions are welcome.

Authors

Edouard Oyallon, Eugene Belilovsky, Sergey Zagoruyko