[Wien] Optimization of monoclinic structure

[Tomas Kana]

Thanks Gavin for reply.
 I just add that OrthoOpt fixes  the volume and 
relaxes simultaneously c/a and b/a ratio of lattice 
parameters using several times x optimize and searching 
the best combination of c/a and b/a. 
Then it moves on for next volume and so on.
It does not change the angles of the lattice.
Tomas 

Předmět: Re: [Wien] Optimization of monoclinic structure

I don't remember.  Probably all parameters are fixed except for one of 
them, then this is repeated separately for each parameter:

A, B, C fixed with changing GAMMA value, then
A, B, GAMMA fixed with changing C value, then
...
B, C, GAMMA fixed with changing A value

"x optimize" or OrthoOpt probably automatically set up the set of 
calculations in this way in a job script like optimize.job and then the 
job script is used to run all the calculations [ 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg16418.html 
].

 From the sounds of it, you are setting up each calculation by hand 
instead of using one of the above scripts/programs to help with that.

For monoclinic optimization, make sure the monoclinic angle (i.e., the 
one angle that is not equal to 90) is set as gamma.  As maybe this could 
cause the "SELECT" error due a symmetry break [ 
https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg12124.html 
].

The "SELECT" error could also be caused by other things.  See the "NO 
ENERGY LIMITS FOUND IN SELECT" on page 231 under section "12 Trouble 
shooting" in the WIEN2k 17.1 usersguide [ 
http://susi.theochem.tuwien.ac.at/reg_user/textbooks/usersguide.pdf ], 
where is says:

"Usually this happens when your input is not ok, or for very ill 
conditioned problems (very rare), or more likely, when “Ghostbands” 
appeared (or some states were missing) because of bad energy parameters 
in case.in1."

input is not ok =  In an optimization, you are distorting the structure 
(changing the lattice parameters).  It is probably straightforward that 
if you distort a structure too much (% change is too large)  while you 
are doing this, you could possible generate a bad case.struct file.

As the above sentence also says, it could be caused by ghost bands. To 
help with that, there is section "12.1 Ghost bands" starting on page 232 
in the WIEN2k usersguide.

A related error might be the QTL-B error.  Refer to the links found in 
the post at:

https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg12625.html

On 10/15/2017 8:26 PM, Shalika R. Bhandari wrote:
  Dear all, Thank you for your suggestions .
   Now I have a bit confusion like while optimizing monoclinic structure 
  does A, B,C,and GAMMA changes at the same time or we need to do them 
  separately?
  Also while running optimization, after first cycle it shows ERROR and 
  stops running. LIKE THIS..
  46.9u 0.0s 0:47.75 98.4% 0+0k 3696+40656io 12pf+0w
  1.3u 0.0s 0:01.59 89.3% 0+0k 73552+35336io 6pf+0w
  clmextrapol_lapw has generated a new RELAX.clmdn
  hup: Command not found.
  changing RELAX.in2c
  changing RELAX.in2_ls
  changing RELAX.in2_st
  changing RELAX.in2_sy
   LAPW0 END
  SELECT - Error
 
      stop error
  ERROR status in RELAX_mon____1.00
 
  I Want some more suggestions to resolve this problem sir.
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