On Fri, Jul 30, 2010 at 09:41:07PM -0400, case wrote:
> On Fri, Jul 30, 2010, InSuk Joung wrote:
> > Also, similar things are in sff2.c
> >
> > line 1265:
> >
> > assert(bi > 0.01);
> > assert(bk > 0.01);
> >
> > Is this really necessary?
>
> I think something is necessary if you really must have bond angles of 180
> degrees. The diehedral angle (and hence its derivative) is undefined there.
> Instead of triggering an assert, one could put in dummy values (as I suggested
> in eff.c), on the assumption that everything will be multiplied by zero later
> on anyway. But we might really want to think about having leap strip out
> zero force constant diehedrals before the prmtop is written, so that this
> problem never comes up....that would be a better solution, since otherwise
> the sff code would have to double check that the force constant really is
> zero.
Is this problem in sleap or only in tleap ?
scott
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Received on Thu Sep 23 2010 - 13:30:07 PDT