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ESPResSo can perform simulations of various physical systems in different ensembles. It is optimized for coarse-grained models and has the following characteristics:

  • ESPResSo is alive! It is actively maintained and refined by members of the Institute for Computational Physics, Stuttgart and contributors from all around the globe.
  • ESPResSo is controlled by python scripts, which gives it its great flexibility (older versions up to 3.3.1 used Tcl).
  • ESPResSo is extensible, which allows users to add new methods and algorithms.
  • ESPResSo is open-source and free (License: GPL3 (GNU General Public License).
  • ESPResSo is parallelized, i.e. it can run on many processors in parallel, some features also can employ a GPU.
  • ESPResSo is portable, i.e. it runs on a wide variety of hardware platforms, like desktop workstations, convenience clusters as well as high performance supercomputers based on POSIX operating systems (e.g. Unix or Linux, OSX).

Methods and Algorithms

ESPResSo contains  a number of advanced algorithms for coarse-grained simulations:

  • Statistical ensembles: NVE, NVT, NPT,  μVT.
  • Non-bonded potentials: Lennard Jones, Buckingham, Morse, Generic tabulated potentials, anisotropic Gay-Berne particles etc.
  • Bonded potentials: Harmonic spring, FENE, generic tabulated bonded potentials, etc.
  • Fast methods for electro- and magnetostatics: e.g. P3M, MMM1D, MMM2D, ELC, dipolar P3M, DLC, MMM2DIC, ELCIC, ICC, LB-EK, SCAFACOS library.
  • Constraints: all or some of the  coordinates of particles can be fixed, various spatial constraints (walls, spheres, pores, …) can interact with the particles.
  • Rigid bodies: arbitrary extended objects can be constructed from several particles.
  • Field coupling: various particle coupling methods to external scalar and vector fields.
  • Dynamic bonding: when particles collide, new bonds can be generated between them to study agglomeration.
  • Hydrodynamics: Lattice-Boltzmann fluid (optionally on a GPU), DPD (Dissipative Particle Dynamics).
  • Analysis: numerous convenient analysis functions exist and advanced observables.
  • Real-time visualization: with a build-in OpenGL visualizer or Mayavi. File format support for trajectory visualization with external tools (e.g. VMD or paraview).
  • Advanced simulation methods for swimmers, immersed boundaries, electrokinetics, particle polarizability, reaction ensemble.

What ESPResSo is not

  • ESPResSo is not Quantum Espresso, which is an integrated suite of computer codes for electronic-structure calculations and materials modeling on the nanoscale.
  • ESPResSo is not a simulation program for all-atom simulations as they are used e.g. for protein simulations! There are many other programs which are more suitable for this kind of simulation, for example GROMACSNAMD or GROMOS.
  • ESPResSo is not ESPResSo++ESPResSo  and ESPResSo++ have common roots and share parts of the developer/user community. However their development is independent and they are different software packages with somewhat different target communities. Please look at the respective website for spotting the differences or attend one of our common schools.