LARGE CODE No 2. - LAMMPS

Since we cannot solve the Schroedinger equation analytically once we go beyond hydrogen-like atoms, approximations are needed. Now we consider atomic scale, Monte Carlo or Molecular Dynamics with classical potentials. This is a molecular dynamics code - we discussed Molecular Dynamics earlier , but ony from an algorithmic viewpoint, not as a code implementation. There are two questions to ask here:

  • Why use a canned code?
  • Why choose LAMMPS?

    The reasons for canned code are several. Own code, or code built up by successive group members is more idealistic. There are not the serious computational issues, such as large matrix inversion which limit DFT applications. In fact several group computations are using our ``own code''. However, good molecular dynamics studies need good statitical physics, and implementation of complicated temperature and pressure ensembles is HARD!!! Also to get large systems, have to do clever parallelization and this is HARD!! So a canned code can simplify these aspects. For smaller systems, with straightforward statistical mechanics, and known or complicated potential choices ``own code'' is preferable, both ideally and in practice.

  • The reasons to choose LAMMPS over other canned codes are simple. It is public domain, well adapted to many computer architectures and there is excellent local expertise, from Dan Mordehai's group in Mechanical Engineering.

    There are many project examples already done in this course, and we will skim over these.

    We will look at the last of these in detail.

    ERAN ZEVULUN
    Molecular Dynamics simulation of lattice defects in Silicon Nitride
    [LAMMPS/AViz - research] complete and graded
    korens_at_TECHUNIX.TECHNION.AC.IL Koren Shreiber
    Visualization of defects in graphene
    [LAMMPS/AViz - research (DM)] This code is being reworked, please do not use meantime
    bbliron_at_TECHUNIX.TECHNION.AC.IL Liron Ben-Bassat
    MD simulation of a silicon crystal crack propagating on the (110)<110> cleavage system
    [LAMMPS - Materials research (DS)]
    Omri Harosh
    Percolation in diamond
    [LAMMPS and AViz - Research] with R. Kalish and A. Silverman - complete and graded
    BACK to LargeCode pages or on to continuum codes