BATSim

BATSim is designed to enable the application of non-affine shear transformations to GalSim images. It works by trasnforming the stamp pixel grid, distorting the location of the pixel centers. When a GalSim image is sampled onto this distorted grid, the resulting image will be sheared due to the transformation of the pixel grid.

Non-affine transforms can simualate complex shear effects such as intrinsic alignment, flexion, and optical field distrotion maps. Custom transform functions can also be passed to Stamp objects.

Installation

The package is not currently available on PyPI while in early development.

First clone the repository:

git clone https://github.com/CMacM/BATSim.git

Then install the package

cd BATSim
conda install --file requirements.txt -c conda-forge
pip install . --user

Potential installation pitfalls:

• The above will install the python package of the dependence GalSim. However, you may need to install the C++ shared library of GalSim, not installed by default with the above installation. Find details on how to do this [here][https://galsim-developers.github.io/GalSim/_build/html/install_pip.html]. You may then need to update your LD_LIBRARY_PATH, LIBRARY_PATH, and CPLUS_INCLUDE_PATH to point to build and include folders for the GalSim C++ shared library.

(repo icon created using images by Frepik and brgfx on Freepik)