Subject: Re: CCL:Geometry Optimisations with Scripts in HyperChem

From: [email-masked] (Joel Polowin)
Date: Fri, 23 Aug 96 17:19:24 -0400

> Date: Fri, 23 Aug 1996 18:05:51 +0100 (BST)
> From: patrick kane <[email-masked]>
> 
>  I am a HyperChem user. When I wish to run molecular mechanics geometry
> optimisations (using MM+) with scripts I find that the termination
> conditions (the RMS gradient and the max number of cycles) and the screen
> refresh period do not change when the script is run. Instead, I need to
> carry out a 'manual' geometry optimization on some molecule (not
> necesarily one of those molecules referred to in the script) with the
> required settings, stop the optimisation after a few seconds and then run
> the script. This is very tedious and I would be very grateful if anyone
> could provide a solution. 
> 
> optim-max-cycles 4000
> optim-convergence 0.01
> optim-algorithm newtonraphson (THIS LINE DOES NOT CAUSE ME A PROBLEM)
> screen-refresh-period 200

The maximum number of cycles *can* be set with the script command.  However,
when you open the Geometry Optimization dialogue box, it automatically
resets the number of cycles to the default value, which is 15 times the
number of atoms.  If you run the optimization with the "do-optimization" 
script command, the optimization will run to the number of cycles that you
specify with "optim-max-cycles".

I find that the "optim-convergence" script command behaves as it should,
and it correctly sets the value in the dialogue box as well.

Several of the script commands for the screen refresh period for dynamics 
and optimization seem to have gotten mixed up; this is in the bug list.
The "screen-refresh-period" script command changes the refresh period
for molecular dynamics but not for geometry optimization.  Currently,
"dynamics-collection-period" changes the collection period for dynamics
and the screen refresh period for optimization.

Joel

------------
Joel Polowin, Ph.D.   Manager, Scientific Support
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