ENCCS is supporting the development of key scientific HPC software in Sweden and providing consultancy and training to adapt the software to forthcoming (pre-)exascale EuroHPC systems. On this page you can find more information on the core software packages we are supporting – ranging from molecular dynamics and electronic structure to climate modeling and computational fluid dynamics codes.

In our work we draw on extensive individual experience in scientific computing and HPC software development which spans many programming languages, parallelization schemes and hardware architectures. We aim to strictly follow and train others in best practices in software development – this includes using version control systems, automated testing, code coverage analysis and continuous integration as well as writing high-quality documentation, adhering to standard coding styles and using well known build systems. We also strive to follow FAIR software principles .

GROMACS is a versatile package to perform molecular dynamics, i.e. simulate the Newtonian equations of motion for systems with hundreds to millions of particles. It is primarily designed for biochemical molecules like proteins, lipids and nucleic acids that have a lot of complicated bonded interactions, but since GROMACS is extremely fast at calculating the nonbonded interactions (that usually dominate simulations) many groups are also using it for research on non-biological systems, e.g. polymers.

VeloxChem solves the Schrödinger equation to study the electronic structure of molecular systems. The program can compute molecular energies and simulate the response of molecules subject to external electromagnetic fields. VeloxChem is built to exploit the aggregate resources of computing systems: from laptops to clusters. It can handle thousands of atoms and leverages a hybrid Python/C++ programming paradigm for fast development without sacrificing performance

Nek5000 is an open-source code for the simulation of incompressible flow. Nek5000 is widely used in a broad range of applications, including the study of thermal hydraulics in nuclear reactor cores, the modeling of ocean currents and the simulation of combustion in mechanical engines. The Nek5000 discretization scheme is based on the spectral-element method. In this approach, the incompressible Navier-Stokes equations are discretized in space by using high-order, weighted residual techniques employing tensor-product polynomial bases.

ICON is a highly versatile next-generation global climate model. The model solves the equations of motion for the atmosphere and ocean and couple these together with unresolved processes such as small scale turbulence, cloud microphysics and radiation. The model code has been designed with parallelization in mind allowing scientists to achieve unprecedented kilometer-scale resolutions, enabling simulations of individual clouds and ocean eddies even on global grids.


ESSENSE is a research code for flow calculations by solving the compressible Navier-Stokes equations. Using a high order finite difference method in combination with summation-by-parts operators and weak boundary conditions makes it possible to efficiently and reliably handle large problems on structured grids for reasonably smooth geometries.