[Wien] LOPW-exhausted for atom 4 PASS 1 had to reduce check 0.010000

[Peter Blaha]

Usually this warning comes for B lattices and a position of high 
multiplicity (24 ??). In general I do not consider this as a problem and 
I doubt that it has anything to do with the force minimization.

This problem is most likely connected with a "mixer" problem in such a 
way, that mixer keeps the non-converged forces in a MSR1a optimizitation 
below the convergence criterium and thus stops the optimization, while 
after switching back to MSR1 the converged forces are again larger than 
expected. This can even go on a couple of times.

The solutions can be:
echo 0.4 > .pratt
run -min ...

or/and  set a very tight convergence criterium (eg. tolf= 0.1 in 
case.inM). With the latter it does not stop at the "false convergence", 
but it may also not stop automatically. Once the positions have moved 
and E-tot settles at a better value, you can manually change to MSR1 and 
check the final converged forces.


Am 19.06.2018 um 18:36 schrieb Rui Costa:
> Dear wien2k users,
> 
> I am trying to minimize the positions of the compound YIG to get forces 
> below 1 mRy/bohr but instead I am always getting forces around 3 
> mRy/bohr, and in every iteration I am getting the warning message: 
> "LOPW-exhausted for atom    4 PASS 1  had to reduce check 0.010000", 
> where atom 4 is the Oxygen and it is the only with free structural 
> parameters.
> 
> I have searched the mailing list 
> ([https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg13899.html] 
> and 
> [https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14393.html]) 
> and it seems that the problem is a low RKmax but I have done the 
> calculations from RKmax=6 to 10 and the warning persists.
> 
> Also, if I do a 1x1x1 P supercell (160 atoms) this warning disappears.
> 
> Should I increase the RKmax until I no longer get the warning or is 
> there an alternative?
> 
> Best regards,
> Rui Costa.
> 
> 
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-- 
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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