On Thu, 26 Jan 2006, Daniel Sanchez Portal wrote: | Dear all, | | I have been checking a little bit the problem commented by | Andrei. From my point of view it seems a problem related to the use of a | interpolation from a (not very dense) grid. | We always have numerical values of S(R) and numerical derivatives. | The derivatives given by the splines seem indeed to be quite consistent | with the behaviour of given also for SR (I am talking now | about the radial part). | However, this behaviour | is not completely correct. If the number of points in the | radial mesh is increased one can see a significant | decrease in the magnitude of the spurious force. | | Daniel |
Dear community, I agree with Daniel but I think this is a slightly different issue; Daniel writes about the numerical accuracy whereas my point was about missing symmetry. And this missing symmetry can be traced to the spherical harmonics part and has no relation whatsoever with the radial integration. I also checked that the error (deviation from zero of what must be zero) can be pushed down by increasing e.g. the k-cutoff in matel, but quite slowly. Best regards, Andrei +-- Dr. Andrei Postnikov ---- Tel. +33-387315873 ----- mobile +33-666784053 ---+ | Paul Verlaine University - Institute de Physique Electronique et Chimie, | | Laboratoire de Physique des Milieux Denses, 1 Bd Arago, F-57078 Metz, France | +-- [EMAIL PROTECTED] ------------ http://www.home.uni-osnabrueck.de/apostnik/ --+
