Subject: Re: [gmx-users] Help!!!!!

[K.A. Feenstra]

Nguyen Hoang Phuong wrote:
> 
> On Wed, 16 Oct 2002, Dmitry Kovalsky wrote:
> 
> > But why it doesn't work if to use simply ouput.gro  from previous steepest
> > descent, without -t option? As I undersand output.gro should contain
> > velocities also? Or I have missed something?
> 
> Dear Dima,
> 
> because output.gro doesn't have high precision. One doesn't need
> velocities while doing minimization.
> 
> In any case, I suggest you should use double precision to get really good
> minimum structure.

In most cases you really do not need that precision. Only for normal
modes analysis is it absolutely necessary. In all other cases, single
precision is absolutely accurate enough, and also the precision in
your output.gro file will be high enough. 

Specifically, if you performed steepest descent minimization, the
precision of the minimization is not much better than that which is
written to the .gro file. Only the output of a conjugate gradients
minimization, when used for normal modes analysis, must be done
in doouble precision and read from the .trr file.

-- 
Groetjes,

Anton
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|        | Anton Feenstra                                            |
| .      | Dept. of Pharmacochemistry - Vrije Universiteit Amsterdam |
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