[Pw_forum] BFGS

[Silviu Zilberman]

sbraccia carlo wrote:
Hi Carlo,

Thanks for the detailed reply, I'll try it out.
Is the hessian in the bfgs implementation given in mass-weighted 
coordinates?

Thanks, Silviu.

>On Wednesday 12 May 2004 04:38 am, Silviu Zilberman wrote:
>  
>
>>Hi,
>>
>>Is there a way to feed an initial guess of the Hessian in the BFGS
>>structural relaxation, instead of the (presumably) default unity matrix?
>>
>>Thanks, Silviu.
>>    
>>
>
>Yes, it is possible: whenever you start a new relaxation the code looks for a 
>file prefix.hess and, if present, the inverse hessian written on that file is 
>used as initial guess (an information message is also printed). If you can 
>generate a good guess for the inverse hessian of your system you have only to 
>write it on a file:
>
>WRITE( unit, * ) SHAPE( inverse_hessian )
>WRITE( unit, * ) inverse_hessian
>
>where inverse_hessian is a 2-dim array. Put this file in the outdir and change 
>the name to prefix.hess (prefix is the keyword set in &CONTROL).
>Anyway, you can find all that you need in the file Modules/bfgs_mdule.f90, 
>SUBROUTINES read_bfgs_file() and  terminate_bfgs().
>
>carlo
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>  
>


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Zilberman Silviu
 
213 Frick Laboratory, Department of Chemistry 
Princeton University
Princeton, NJ 08544, USA
 
phone: 609-258-1834
fax:   609-258-6746
silviu at Princeton.EDU
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