Re: [SIESTA-L] Tips for symmetry?

2009-06-25 Thread Vasilii Artyukhov
There's also the GridCellSampling block that is intented for this, too.

2009/6/25 David Strubbe dstru...@berkeley.edu

 Ben,

 Your symmetry is probably not being broken by numerical noise, which is all
 that those tolerances will affect, but rather by the real-space mesh, i.e.
 the eggbox effect.  Increase the mesh cutoff to reduce the symmetry
 breaking.  Even better, especially if your system has the symmetry of the
 lattice, make the mesh respect the symmetry of your system by e.g.
 translating the atoms to put a mesh point on the inversion center of your
 system.  Otherwise, you can always explicitly symmetrize your coordinates by
 hand after some steps, and continue from there.

 David Strubbe
 UC Berkeley


 On Wed, Jun 24, 2009 at 3:16 PM, Ben Martin g.ben.mar...@gmail.comwrote:

 Hi all,

 Does anyone have any tips for getting better symmetry for geometry
 optimizations/relaxations (MD.typeofrun CG). Right now my relaxations are
 symmetric only to the second or third decimal place, but I would like much
 better symmetry (like to the 6th decimal place).

 I have tried making the DM.tolerance = 10^-7 and DM.EnergyTolerance =
 10^-7, but that doesn't seem to help much. Does anyone have any tips for
 getting really good symmetry with SIESTA?

 Thanks,
 Ben





[SIESTA-L] Tips for symmetry?

2009-06-24 Thread Ben Martin
Hi all,

Does anyone have any tips for getting better symmetry for geometry
optimizations/relaxations (MD.typeofrun CG). Right now my relaxations are
symmetric only to the second or third decimal place, but I would like much
better symmetry (like to the 6th decimal place).

I have tried making the DM.tolerance = 10^-7 and DM.EnergyTolerance = 10^-7,
but that doesn't seem to help much. Does anyone have any tips for getting
really good symmetry with SIESTA?

Thanks,
Ben