GPUDEM is a an open source GPU based discrete element solver using CUDA, currently in beta version. The code is provided under the GNU GENERAL PUBLIC LICENSE.
Download the repository, install CUDA (compute capability 8.0 or above required for full functionality) and a C++17 compiler. The code then can be compiled using the given makefile in the examples or the following command
nvcc -o GPUDEM -std=c++17 --gpu-architecture=sm_XX -maxrregcount=128 -I/path/to/GPUDEM
where XX is your CUDA compute capability.
The code is documented using doxygen. For usage refer to the provided examples.