Hi Benoit,

On Tue, Aug 28, 2012 at 3:10 PM, benoit-leblanc
<blebl...@materialsdesign.com> wrote:
> Dear All,
>
> Sorry for the mess I've created. In fact I started to work from the
> latest stable version 2.3.1. And then we I got the SVN version in, I
> did not check that there was some update in between for the Conformer
> Search. Shame on me!

No problem, this can happen. Thanks for the contribution.

> So I got the latest version before my commit (4914), and
> merged with my changes, and commited (r4992).
> So the virtual issues are gones, and latest classes
> OBMinimizingEnergyConformerScore and  OBMinimizingRMSDConformerScore
> are back in business.
>
> Note the in the OBMinimizingEnergyConformerScore, I also added a map
> to bookeep steepest descent + energy result. As a example, in a test
> run I made, it gave  9029 request  for  681 actual computations.
> I also noted that
>
>    OBMinimizingEnergyConformerScore::Preferred ()
> was set to Highest instead of Lowest (since we focus on the lowest
> minimized energy score).
>
> In the  OBStericConformerFilter::IsGood method, there was an issue
> with the  value of square distance between 2 atoms. It was originally
> set as:
>> double distanceSquared = sqrt (dx*dx + dy*dy + dz*dz);
> And I guess that, in order to save sqrt compuation time, the intention  was
> to set it as:
>> double distanceSquared = dx*dx + dy*dy + dz*dz;
> As it is later compared with squard cutoff.
> Moreover the VdW cutoff is applied to all non directly bonded atoms,
> so discarding anything, since e.g. 1-3 carbons in an alcane chain will
> be below the sum of VdW radii.
> For now I fixed it by applying a factor of 0.6, eg.:
>>       double vdwCutoff = 0.6 * (etab.GetVdwRad(atom1->GetAtomicNum())
>>                                 + etab.GetVdwRad(atom2->GetAtomicNum()));
> I guess this could be improved by discarding 1-3 and 1-4 bonded atoms,
> and maybe use a factor of 0.85 or 0.9, as in the end distances below
> the VdW radii will reflect in the energy.
>
> Hope this will help... in the end.

The GA conformer search was an experiment so it did not receive robust
testing and validation. The tautomer code is also experimental and
perhaps we should have a separate repository or folder for these?

Tim

>
> BenoƮt
>
>
>
>
> --
> View this message in context: 
> http://forums.openbabel.org/r4990-breaks-things-tp4655401p4655411.html
> Sent from the openbabel-devel mailing list archive at Nabble.com.
>
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