[ESPResSo-devel] Some user feedback

[Kai Grass]

Hi Espresso developers,

in Canada I got some feedback on our beloved software package that I'd like to share with you.

Bugs:

- Pore constraint doesn't check absolute coordinates, i.e. if you have a pore at say (L-0.5) with a interaction range of 1, particles that come from the next box only "see" the pore once they are in the primary simulation box (at L). Same might apply for cylinder, but is not a problem for walls due to their orientation.

- Writevsf runs out of "labels (O,C,N,Fe,...)" if too many (>6?) different types are used. Currently just blanks are written to the structure file which renders it useless as the format is screwed up. There should at least be a warning, better a default type that is used.

Inconveniences:

- Constraint use only LJ potential. This might cause problems if you have a confined system with high particle density and you are forced to use LJ-force cap for equilibration. Can be circumvented by using a different potential for inter particle interactions and constraints.

Feature requests:

- Fully delete interactions, instead of just setting epsilon=0 or r_cut=0

- Different cell systems for different interactions (don't know if the speed up outweighs the additional overhead)

- Different Langevin friction for different particle types, i.e. to model different sized particles

I hope, you appreciate these comments from happy users ;)

Greetings,

Kai

PS: Is there a reason why www.espresso.mpg.de is down?

--

Dipl. Phys. Kai Grass

Frankfurt Institute for Advanced Studies (FIAS)

Room 2|403

Ruth-Moufang-Strasse 1

60438 Frankfurt am Main

Germany

phone: +49 69 798 47533

fax:   +49 69 798 47611

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web:   www.fias.uni-frankfurt.de/~grass