big jumps in E (Re: [Wien] a question on convergence)

[Peter Blaha]

> If so I'd be interested in possible causes of big jumps (1000s Ry) in
> energy between two values. For me this occurs with a 108 atom system, like
> so:
>
> :ENE  : *WARNING** TOTAL ENERGY IN Ry =       -29584.775822
> :ENE  : *WARNING** TOTAL ENERGY IN Ry =       -29594.018681
> :ENE  : *WARNING** TOTAL ENERGY IN Ry =       -55274.088758
> :ENE  : *WARNING** TOTAL ENERGY IN Ry =       -29618.620985
> :ENE  : *WARNING** TOTAL ENERGY IN Ry =       -29643.144369
> :ENE  : *WARNING** TOTAL ENERGY IN Ry =       -55273.997039
> :ENE  : *WARNING** TOTAL ENERGY IN Ry =       -29670.361236
>
> One of the numbers, -55274, is reasonable (based on energies of
> constituent free atoms). The following warning also appears in the scf
> file:
>
> :WARN :      WARNING: Not all eigenvectors are orthogonal
>
> Matrix sizes are 12934, and I'm using the mpi version of the code
> (with NMATMAX=40000). I think scalapack may have been pushed beyond its
> limits.

a) How does the charge convergence evolve ? (grep :DIS case.scf)
   Dos it converge ?

b) could it be that you have done many iterations without savong the results ?
   grep :ITE case.scf   Do you have the same iteration number twice (several
   times) in the scf file ?

The warning of scalapack is most likely not too seviere. For speedup some
small non-orthogonality is accepted for "clustered" eigenvalues.

If :DIS looks converging and :ITE has identical numbers, just do a
"save_lapw" during the run and continue (maybe only 3 iterations are necessary.

If this does not solve the problem, I need a little more info.

Regards

                                      P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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