How Come the ATK-VNL Package is Larger than a Typical DFT Code

If you downloaded and installed ATK-VNL, you probably noticed it’s quite a large package, almost 700 MB to download and about 1.2 GB to install (a bit more even on Mac). That’s because you are not just getting a bit of code for DFT calculations - ATK-VNL is a complete platform for atomic-scale simulations, which even includes development tools for creating extended functionality. But let us explain this in a bit more detail. First of all, Atomistix ToolKit (ATK) and Virtual NanoLab (VNL) run out of the box on pretty much any Windows, Linux or Mac OS X machine. There is no need for the user to compile source code, or even install any additional libraries (except on Linux perhaps a few that belong to the operating system but might not be installed by default). Instead, ATK and VNL are precompiled and fully optimized for both laptop and desktop graphical performance, as well as for running in HPC environments like clusters and big servers. To achieve this (which is not entirely easy!), the package needs to contain a lot of components, which takes up a bit of space. One should also note that with ATK, you get not only an easy-to-use GUI and a powerful quantum-chemistry code; you also get a development environment that can be used to add functionality. Specifically, you get a complete Python 2.7 interpreter with the scientific Python libraries numpy, scipy and matplotlib compiled against the high-performance MKL (Math Kernel Library) from Intel. Additional numerical and scientific libraries provided include

Having all these packages, readly available at their fingertips, enables users to easily develop additional functionality on top of ATK. And not only for the backengine; the user can also create new plugins in the GUI, using the provided OpenGL (with pyopengl and glew), PyQt4 (with Qt5 bindings) library (Tcl/Tk is also included). Now, as if this this was not enough, a few complete atomistic simulation code packages are also included:

  • The classical empirical potential code TremoloX - the foundation of ATKClassical
  • The DFT codes ABINIT and FHI-aims - for which ATK provides a rich Python interface

Finally, a large part of the package is actually taken up by data files:

With this, we hope you will appreciate why the installer package for ATK is rather large! We are however constantly working on optimizing the package size to avoid it growing further, even as we add new functionality and libraries. In conclusion, you shouldn’t really compare the download of ATK-VNL to, say, the source code package of Quantum Espresso or VASP - but rather, view it as something on the level of Photoshop or Microsoft Office.