Ensure environment variable GEMINI_ROOT is set to the top-level directory where Gemini3D is installed. On Linux and MacOS, environment variables are set in ~/.profile (Linux) or ~/.zprofile (macOS) like:
export GEMINI_ROOT=/home/username/libgem_gnuUse the correct path on your system, not the literal text above.
Windows users can use Intel oneAPI to build Gemini3D and associated libraries natively from Windows. Another choice is to generate the simulation files on Windows Matlab, then access those files from WSL to run the simulation. That is, the Gemini3D code is compiled in Linux under WSL and run there.