This repository contains a standalone implementation of the GFN0-xTB method (https://doi.org/10.26434/chemrxiv.8326202.v1), adapted from the xtb code.

The default CMake and meson builds compile a statically linked library (libgfn0.a) that can be linked in other projects.

main.f90 in testprog/ demonstrates the in-code usage.

Make sure you have the following dependencies installed:

• CMake and make, or meson and ninja build systems
• Fortran and C compilers (e.g., gfortran/gcc or ifort/icc)

Follow these steps to build the project:

1. Create a build directory and navigate to it

   mkdir _build
   cd _build

2. Export the compilers (here for example ifort/icc) and depending on your chosen build system set up the build:

   • generate the build files using CMake:

     FC=ifort CC=icc cmake ..

   • generate the build files using meson:

     FC=ifort CC=icc meson ..

   I you wish to build the test-binary, add -Dbuild_exe=true to either the cmake or meson setup command.

3. Depending on your chosen build system, build the project. If you have multiple cores/processors, you can speed up the build process by specifying the number of cores to use with the -j option. For example, to use 4 cores:

   • With CMake/make:

     make -j4

   • With meson/ninja:

     ninja -j4

To clean the build files, simply delete the build directory:

rm -rf _build