does sim:enable-fast-dipole-fields=true work at all?

[Gabriel Chaves]

Hello Vampire Users.

I am trying to use fast-dipole calculations in vampire.

But when i write

sim:enable-fast-dipole-fields=true

I get the following error:

Error - Unknown control statement 'sim:enable-fast-dipole-fields' on line 15 of input file

Can anyone tell me the right spelling?

Thank you very much.

Gabriel

[Gabriel Chaves]

I have managed to get the fast-dipole calculation working. It seems that this

dipole:solver = tensor

makes fast dipole calculations the default. The message from Vampire no says this:

Initialising dipole field calculation

Fast dipole field calculation has been enabled and requires 213.5 MB of RAM

Thank you all!

Gabriel.

[Richard Evans]

Hi Gabriel, All,

Yes - that is the new default solver. For background, there was a problem with the original implementation when using non-cubic cells (caused by truncation). This is fixed in the new implementation by calculating a dipole tensor between atoms for nearby cells (default range is 12 cell lengths). The basic methodology is described in the paper by Bowden et al [ Inter and intra macro-cell model for point dipole–dipole energy calculations, G J Bowden, G B G Stenning and G van der Laan, Journal of Physics: Condensed Matter, Volume 28, Number 6 (2016) ]

Other options in the develop branch include "atomistic". "FFT" and "hierarchical" (Order N) are currently in-progress and should be much faster for larger systems.

All the best,

Richard

[Richard Evans]

I forgot to mention that details of the implementation in VAMPIRE and tests done by Andrea Meo are available in his PhD thesis:

http://etheses.whiterose.ac.uk/22730/