Sh 02sh03 octopus: a first- princip. M.A.L. Marques, A. Castro, G.F. Bertsch, A. Rubio.

PROGRAM SUMMARY
Title of program: octopus
Catalogue identifier: ADQX
Ref. in CPC: 151(2003)60
Distribution format: tar gzip file
Operating system: GNU/Linux, AIX, Tru64 Unix, Irix
High speed store required: 50MK words
Number of bits in a word: 32
Number of lines in distributed program, including test data, etc: 82269
Keywords: Electronic structure, Linear response, Non-linear response, Non-adiabatic dynamics, Density-functional theory, Time-dependent density-functional theory, Local-density approximation, Generalized-gradient approximation, Real-space methods, Solid state physics, Band structure, Other.
Programming language used: Fortran, C, bison, sh
Computer: IBM SP3 .

Nature of physical problem:
Interaction of quantum finite systems with classical electromagnetic fields. The electronic degrees of freedom are described within the Kohn-Sham form of the time-dependent density functional theory, while nuclei are treated as classical point particles.

Method of solution:
The electronic wave-functions are discretized in real space using an uniform mesh, and are propagated in real time using nearly unitary propagation schemes. Pseudopotentials are normally used to describe the electron-ion interaction, although model interactions can also be employed. The electromagnetic fields are treated classically either in the length or in the velocity gauge.

Restrictions:
The present version only handles finite systems and classical nuclei. In the near future the code will handle periodic structures.

Unusual features:
The program can be run in either one or three dimensions (we plan to support two dimensions and several categories of periodical systems in future versions). octopus makes use of a very sophisticated, but user-friendly input system.

Typical running time:
For the benzene example (section 7.1), the ground-state calculation took around 15 minutes (in a single processor), while each of the time-evolutions took around 2 days (using 8 processors). These numbers refer to an IBM SP3.

Additional comments:
Libraries required: BLAS (http://www.netlib.org/blas/), LAPACK (http://www.netlib.org/lapack/), FFTW (http://www.fftw.org/), GSL (http://www.gnu.org/software/gsl/), MPI (http://www-unix.mcs.anl.gov/mpi/). All of these are available under open-source licences. The code was parallelized with MPI.