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which paramiter can control the maximum step?
Date: 2019/12/13 21:50
Name: Liu Jie   <15284076358@163.com>

Dear users and developers!i'm a new in Openmx.when i use the openmx to implementation geometry optimization,i'll get a output file with the extension '.SD' displaying the history of optimization.The fourth column indicates the 'Maximum step' in this file,but the value of every MD step is the same value,i want to kown which parameter will influence this value.your answer will be greatly appreciated.
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Re: which paramiter can control the maximum step? ( No.1 )
Date: 2019/12/14 12:28
Name: T. Ozaki

Hi,

The maximum step is introduced to avoid a too large structural change which may cause
some instabilities during the structural optimization, and cannot be controlled by
users' input file.

However, if you want to control it, the pre-defined value can be changed in MD_pac.c.
The default value in Ver. 3.9 is set as

#define Criterion_Max_Step 0.20

At your own risk, you can change it and see how it affects to the convergence.

Regards,

TO

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Re: which paramiter can control the maximum step? ( No.2 )
Date: 2019/12/14 17:31
Name: Liu Jie  <15284076358@163.com>

Thank you very much T. Ozaki!i still have questions about the ouput files generated by Openmx3.8.i can't figure out the meaning of the items in some output files,i have tried to search the relevant materials in the manual of openmx3.8 and on the internet,but i failed.i want to know where i can get the resouces about the detailed information of output file.if you have relevant materials about that,please recommend it to me or send it to my email.

best wishes!
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Re: which paramiter can control the maximum step? ( No.3 )
Date: 2019/12/14 20:56
Name: T. Ozaki

Hi,

The most of information stored in the out file is explained in the manual and
the out file itself.

What information puzzles you?

Regards,

TO
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Re: which paramiter can control the maximum step? ( No.4 )
Date: 2019/12/15 21:18
Name: Liu Jie  <15284076358@163.com>

Hi,T. Ozaki.i can't figure out the output file with extension '.md' and '.ene'.Although i have leared they mean 'Geometrical coordinates at every MD step' and 'Values computed at every MD step' in the manual,i still want to kown the meaning of every column in the output file.
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Re: which paramiter can control the maximum step? ( No.5 )
Date: 2019/12/16 09:37
Name: T. Ozaki

Hi,

The 'ene' file is explained at
http://www.openmx-square.org/openmx_man3.9/node59.html
http://www.openmx-square.org/openmx_man3.9/node60.html

In addition, the more details can be found in the relevant source code 'iterout_md.c'.

As for the 'md' file, the details can be found in the relevant source code 'iterout.c'.
The format is similar to a 'xyz' file, but the header part contains more information
such as lattice vectors. Please make sure that the 'md' file can be visualized with
OpenMX Viewer by just dragging and dropping into the website of OpenMX Viewer.


Regards,

TO
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Re: which paramiter can control the maximum step? ( No.6 )
Date: 2019/12/16 22:36
Name: Liu Jie  <15284076358@163.com>

Thank you T. Ozaki.I am still confused with the '.xyz' file.I know it means the 'The final geometrical structure obtained by MD or the geometry optimization'.However,i will get the file during the geometry optimization.I want to know whether the file will be generated at every MD step.Still,there is no lattice vecter in this file.Is it means the lattice vecter is familiar to that in the input file.
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Re: which paramiter can control the maximum step? ( No.7 )
Date: 2019/12/16 23:02
Name: T. Ozaki

Hi,

As for the format of 'xyz' file, please take a look at
https://en.wikipedia.org/wiki/XYZ_file_format
The 'xyz' file does not include the lattice vectors.

The 'xyz' file is not generated at every MD step in OpenMX calculations,
but the file is saved at once after all the MD loop finished.

When the geometry optimization is performed (I mean no variable cell relaxation),
the lattice vectors are the same as in the input file, while they can be different
from those in the input file when you perform the variable cell optimization.

The optimized lattice vectors in the variable cell optimization can be found in
filename.dat# where 'filename' stands for the name of your input dat file.

Also, the change of the lattice vectors can be traced by looking at the comment line
of the 'md' file. Please notice that the format of the 'md' file is equivalent to
that of 'xyz' file, but the lattice vectors are stored in the comment line, which
allows the OpenMX Viewer to visualize the change of the lattice vectors.

Regards,

TO
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Re: which paramiter can control the maximum step? ( No.8 )
Date: 2019/12/17 19:49
Name: Liu Jie  <15284076358@163.com>

Thank you T. Ozaki.I have viewed the 'md2',its format is equivalent to
that of 'xyz' file.However its unit is not familar to that of the input file.I take the fractional coordinate in the input file,but the 'md2' is not in fractional coordinate.So i want to know what unit it used,cartisian or AU?
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Re: which paramiter can control the maximum step? ( No.9 )
Date: 2019/12/17 20:19
Name: T. Ozaki

Hi,

It is the Cartesian coordinates in Angstrom unit.

Regards,

TO
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Re: which paramiter can control the maximum step? ( No.10 )
Date: 2019/12/18 12:01
Name: Liu Jie  <15284076358@163.com>

Thanks for your answers T. Ozaki.

Best wishes!
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