[molpro-user] optimization restart

[Zdenek Futera]

Dear Jacky,

restart of optimization procedure is possible from binary restart file
2. If you have that file, then the following input should work:

***,
file,2,name_of_restart_file
hf
ccsd(t)
optg
---

Best wishes,

Zdenek




Jacky LIEVIN wrote:
> Dear Zdenek and Ricardo,
>
> reading your discussions in the molpro mailing list, I'm wondering if
> you could help me in answering to a basic question: how can I restart
> a CCSD(T) geometry optimization from the last computed step?
> I have tried different things but without success and the manual does
> not give practical informations
> Many thanks for your help
>
> Jacky
>
>
> Le 3 avr. 09 à 10:48, Zdeněk Futera a écrit :
>
>> Dear Ricardo,
>>
>> Thank you for your answer.
>>
>> Our QM/MM interface works according this optimization scheme:
>>
>> a) QM program computes wave function, energy and gradient on QM part
>> of system
>> b) MM program computes energy and forces
>> c) QM/MM script scales gradients and sums energies according to QM/MM
>> formulation
>> d) new gradients on atoms in QM part are used by QM program for
>> creation of new coordinates
>> e) scaled forces on MM atoms are used by MM program and new
>> coordinates are computed
>> f) whole structure is comleted and convergency criteria are checked
>> by QM/MM script
>>
>> so I don't try to use Molpro for the whole system but for QM part
>> only (no more than 100 atoms).
>> I tried to restart OPTG, because I thought that all the information
>> from restart file (coordinates and gradients) should be read and used
>> and only new coordinates should be computed in first step but it
>> doesn't work. You are right, OPTG is automatic optimizer and is not
>> suitable for this job. On the other hand I can evaluate gradients by
>> FORCES directive but I didn't find any command for computing new
>> structure from these forces (something like one step by Quadratic
>> steepest descent method, for example) and that's why I'm looking into
>> the source code and searching for place where to change it.
>>
>> Best wishes
>>
>> Zdenek
>>
>>
>> ______________________________________________________________
>>> Od: rmata at cii.fc.ul.pt
>>> Komu: Zdenek Futera <futera.zd at centrum.cz>
>>> CC: molpro-user at molpro.net
>>> Datum: 02.04.2009 10:49
>>> Předmět: Re: [molpro-user] optimization restart
>>>
>>> Dear Zdenek,
>>>
>>> In a QM/MM implementation you need a program for computing the QM
>>> gradient (in your case Molpro), a program for the MM gradient (in your
>>> case Amber) and some subroutines which can:
>>>
>>> a) call both programs,
>>> b) retrieve the two gradients,
>>> c) build the total QM/MM gradient,
>>> d) based on the gradient do an optimization step and
>>> e) go back to step a)
>>>
>>> Apparently, you have written some routines for steps a)-c), and want
>>> to use Molpro optimization routines to do d), I guess... my question
>>> would be, why?
>>>
>>> Since Molpro is a QM program, it has been coded to handle small
>>> systems. Surely you can change the default maximum number of atoms
>>> (200), but if you are working with more than a thousand atoms, you
>>> have to input a gradient for those thousand atoms. This would require
>>> a new compilation, using an extremely large number of maximum atoms. I
>>> wouldn't advise you to do so. The normal procedure when building a
>>> QM/MM interface is either to write your own optimizer, or perhaps to
>>> use the MM program, which contrary to Molpro has been coded to handle
>>> large systems. It may even have some handy tools for optimization
>>> (like hybrid cartesian-internal coordinates algorithms).
>>>
>>> Also, if you happen to take a look at the Molpro manual, OPTG is for
>>> automatic optimizations, that means, you deliver the control to Molpro
>>> and he will call the gradient program and perform optimization steps
>>> until he finds a minimum. What you were looking for is another keyword
>>> which you will likewise find described in the Manual.
>>>
>>> But again, it is unwise to use Molpro for step d).
>>>
>>> Best wishes,
>>> Ricardo
>>>
>>> On Wed, Apr 1, 2009 at 10:37 AM, Zdenek Futera
>>> <futera.zd at centrum.cz> wrote:
>>>> Hello!
>>>>
>>>> I try implement interface between Molpro (ver. 2006.1) and Amber in
>>>> order to do QM/MM calculations (it is script based system similar to
>>>> ChemShell). During QM/MM optimization I calculate energy and gradients
>>>> on some structure then I change these gradients according to QM/MM
>>>> scheme and then I need to restart Molpro from these gradients and
>>>> compute new structure.
>>>> I found out that gradients are saved in restart file 1 in record
>>>> 700 and
>>>> I can rewrite them there. Is it possible to restart from this changed
>>>> file 1, read coordinates and gradients and compute only new
>>>> coordinates?
>>>> I guess I have to change source code, because when I try restart OPTG
>>>> procedure new gradients are calculated from the last structure in file
>>>> 1. Is there any easier way than change the source code? And if not
>>>> which
>>>> part of the source code should I change to do it in easiest way? Could
>>>> you please give me an advice?
>>>>
>>>> Best regards
>>>>
>>>> Zdenek Futera
>>>>
>>>> _______________________________________________
>>>> Molpro-user mailing list
>>>> Molpro-user at molpro.net
>>>> http://www.molpro.net/mailman/listinfo/molpro-user
>>>>
>>>
>>
>> _______________________________________________
>> Molpro-user mailing list
>> Molpro-user at molpro.net
>> http://www.molpro.net/mailman/listinfo/molpro-user
>
>
> _____________________________________
> Jacky Liévin
> Service de Chimie Quantique et Photophysique
> Université Libre de Bruxelles, CPi 160/09
> 50 av F.D. Roosevelt
> B-1050 Bruxelles
> Belgium
> Tel: +32-2-650 4089
> Fax: +32-2-650 4232
> _____________________________________
>
>
>