Welcome to gratopy’s documentation!

The gratopy (Graz accelerated tomographic projections for Python) toolbox is a Python3 software package for the efficient and high-quality computation of Radon transforms, fanbeam transforms as well as the associated backprojections. The included operators are based on pixel-driven projection methods which were shown to possess favorable approximation properties. The toolbox offers a powerful parallel OpenCL/GPU implementation which admits high execution speed and allows for seamless integration into PyOpenCL. Gratopy can efficiently be combined with other PyOpenCL code and is well-suited for the development of iterative tomographic reconstruction approaches, in particular, for those involving optimization algorithms.


  • Easy-to-use tomographic projection toolbox.

  • High-quality 2D projection operators.

  • Fast projection due to custom OpenCL/GPU implementation.

  • Seamless integration into PyOpenCL.

  • Basic iterative reconstruction schemes included (Landweber, CG, total variation).

  • Comprehensive documentation, tests and example code.

The fanbeam projection of a walnut and gratopy’s Landweber and total variation reconstructions (from left to right).
_images/walnut_sinogram.png _images/landweber.png _images/total_variation.png

Indices and tables