[CP2K-user] [CP2K:11230] Cell optimization of layered material, convergence vs K_POINTS

[Daniele Ongari]

Dear prof. Hutter,
thanks for your advice.

 I tried and:
1) EPS_DEFAULT E-12 and E-14 did not fix the problem
2) &CELL_REF 
(https://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/QMMM/CELL/CELL_REF.html) 
did not work: I'm not sure if I chose the settings correctly, being a non 
orthogonal cell. However, what is this command supposed to do? I could not 
find a proper reference to read more.
This is what  I used:
   &SUBSYS 
      &CELL 
         A  30.1669436651   0.0             0.0            
         B  -15.0834720617  26.1253399655   0.0            
         C  -5.88681146004e-16 1.15003884889e-16 8.07826742778  
         &CELL_REF
    A   35.0   0.0  0.0
            B  -20.0  30.0  0.0
            C    0.0   0.0 10.0
         &END CELL_REF
      &END CELL

3) LBFGS did work but now I'm a little confused/worried, how is the "low 
memory" version of  BFGS supposed to be more stable? Is it always a good 
choice for my crystals, e.g, with a number of atoms that goes from 50 to 
>1000?

Finally, if it is a problem with the optimizer, why did it work with 
kpoints or doubling the UC?

Here is the plot of my results:

Thank you very much for your help!

Daniele

[image: Screenshot from 2019-02-14 17-53-59.png] <about:invalid#zClosurez>












-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190214/0ee8c207/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Screenshot from 2019-02-14 17-53-59.png
Type: image/png
Size: 91553 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190214/0ee8c207/attachment.png>