[xcrysden] Re: How does xcrysden calculate and show the length of the force!

[Yingli Niu]

Dear Tone,

  I have download:
http://www.xcrysden.org/download/xc-pre1.5b-linuxPC-static.tar.gz

  When I used xcrysden to open an axsf file, clicked
"Display", then selected "Forces", the force vectors
appeared on the screens! 

  Then I clicked "Modify", clicked "force setting",
the "Forces: Setting" panel appeared. 

  I wanted to change "Length Factor" and other
parameters. But I found that I could not input number
from keyboard except "Length Factor for arrow-cap".

  It meant that I could not change the number in the
input-box except "Length Factor for arrow-cap".

  But when I used the old version xcrysden, which had
the bug of force length, it could run normally!

  What was the problem?

Regards!

Yingli

> Yingli Niu wrote:
> >   Have you ever plot forces using xcrysden?
> > e.g. there are 2 atoms in the primitive
> > cell(case.xsf):
> > 
> > 6  0.00 0.00 0.00  0.00 0.00 1.00
> > 6  0.25 0.25 0.25  0.00 0.00 2.00
> > 
> > Surely you can set the data:
> > 
> > 6  0.00 0.00 0.00  0.00 0.00 1.00
> > 6  0.25 0.25 0.25  0.00 0.00 3.00
> > 
> > But you will find the length of force of atom 2 is
> > more longer than atom1. It is not 1:2  or 1:3 .
> > 
> > Is it a bug?
> 
> Yes, it is. Thank you very much for spotting it. The
> size of the force
> was, unfortunately, accounted twice, so the scaling
> was quadratic and
> not linear.
> THIS IS A SEVERE BUG. For everyone that uses the
> force-feature of
> xcrysden, you may wish to download the fixed version
> from:
> 
> Linux static version:
>
http://www.xcrysden.org/download/xc-pre1.5b-linuxPC-static.tar.gz
> 
> Sources:
>
http://www.xcrysden.org/download/xc-pre1.5b-src.tar.gz
> 
> 
> > Where is the code the plot the force?
> 
> It is in C/xcForces.c and C/forces.c. The bug was in
> the first file.
> 
> Regards, To
>http://www.xcrysden.org/download/xc-pre1.5b-linuxPC-static.tar.gz

Sources:
http://www.xcrysden.org/download/xc-pre1.5b-src.tar.gz"


 
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