[Pw_forum] problem in relaxation by using bfgs

[Paolo Giannozzi]

On Dec 22, 2006, at 9:20 , Javad hashemifar wrote:

> I am trying to relax a tetragonal interface supercell at different
> values of vertical lattice parameter (celldm(3)). I am using
> calculation=relax and the namelist IONS is as follows:
>
> ion_dynamic = bfgs
> bfgs_ndim    = 3,
> pot_extrapolation = "second_order",
> wfc_extrapolation = "second_order",
>
> [...] For some values of celldm(3) every thing is OK and the system
> relax well and both etot_conv_thr and forc_conv_thr satisfies. But in
> some other values of celldm(3) the calculation stops with the
> following error:
>
> from checkallsym : error #         1
> some of the original symmetry operations not satisfied

we tried your test and actually there is a problem, but we don't
know what the problem is. Could you please verify if the error
happens also if you remove the line
    bfgs_ndim    = 3
? Paolo
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Paolo Giannozzi, Democritos and University of Udine, Italy