This project is an effort to create a library implementation of the extended tight binding (xTB) Hamiltonian which can be shared between xtb and dftb+.
Goals of this project are
- create a high-level interface to the extended tight binding methods
- allow low-level access to the components forming the actual energy expression
- provide a framework to handle and manipulate parametrization data
Explicit non-goals are
- provide functionality beyond singlepoint calculations in this library (like geometry optimization or molecular dynamics)
Installation
Conda package
This project is packaged for the conda package manager and available on the conda-forge channel. To install the mamba package manager we recommend the mambaforge installer. If the conda-forge channel is not yet enabled, add it to your channels with
Once the conda-forge channel has been enabled, this project can be installed with:
If you want to enable the Python API as well install
It is possible to list all of the versions available on your platform with:
Now you are ready to use tblite.
FreeBSD Port
A port for FreeBSD is available
In case no package is available build the port using
For more information see the tblite port details.
Building from source
To build tblite from the source code in this repository you need to have a Fortran compiler supporting Fortran 2008 and one of the supported build systems:
- meson version 0.57.2 or newer, with a build-system backend, i.e. ninja version 1.10 or newer
- cmake version 3.14 or newer, with a build-system backend, i.e. ninja version 1.10 or newer
- fpm version 0.3.0 or newer
To build this project from the source code in this repository you need to have
- a Fortran compiler supporting Fortran 2008
- meson version 0.57.2 or newer
- a build-system backend, i.e. ninja version 1.10 or newer
- a LAPACK / BLAS provider, like MKL or OpenBLAS
Meson is the primary build system and provides feature-complete functionality of this project. CMake and fpm support are available but the functionality of the project is limited. Currently, tblite support GCC 8 and newer or Intel 18 and newer.
Detailed installation instruction are available in the project documentation under the installation category.
Building with meson
Optional dependencies are
- asciidoctor to build the manual page
- C compiler to test the C-API and compile the Python extension module
- Python 3.6 or newer with the CFFI package installed to build the Python API
Setup a build with
You can select the Fortran compiler by the FC environment variable. To compile and run the projects testsuite use
To run the more extensive testing for the available parametrizations use
If the testsuites pass you can install with
This might require administrator access depending on the chosen install prefix. For more details see the meson installation instructions.
Usage
This project provides multiple entry points for different usage scenarios. The simplest way to check out this project is by using the command line driver.
Command line interface
The tblite runner executable provides full access to the implemented Hamiltonians, with the tblite-run subcommand. You can run a single point calculation by providing a geometry input with
To export a parametrization use the tblite-param subcommand
The parameter file can be inspected or modified and than used to perform single point calculations with
A preliminary interfaces for the parameter optimization is provided by the tblite-fit subcommand. By providing a external command to evaluate the data set in the input file and setting the parameters to relax the fit can be started with
The provided external program can callback to the main program to evaluate single points or create differences between data outputs using the tblite-tagdiff subcommand. By adding the --dry-run option the setup of the parameter optimization can be inspected and with --copy copy.toml the input settings can be dumped for user inspection and tweaking.
For more details on all available subcommands checkout the tblite(1) man page and the respective subcommand man pages.
Documentation
The user documentation is available at readthedocs. Additionally, the doxygen generated API documentation is available here.
To build the user documentation locally we use sphinx, install the dependencies you can use the mamba package manager
The documentation is build with
You can inspect the generated documentation by starting a webserver
And open the down URL in a browser.
Contributing
This is a volunteer open source projects and contributions are always welcome. Please, take a moment to read the contributing guidelines on how to get involved in tblite.
License
This project is free software: you can redistribute it and/or modify it under the terms of the Lesser GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This project is distributed in the hope that it will be useful, but without any warranty; without even the implied warranty of merchantability or fitness for a particular purpose. See the Lesser GNU General Public License for more details.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Lesser GNU General Public license, shall be licensed as above, without any additional terms or conditions.
