[gmx-users] definition of "eigenvector" in gromacs

[Mark Abraham]

lulz, that's gold! Now, is that too long for an end-of-mdrun GROMACS quote?
:-)

Mark

On Mon, Mar 9, 2015 at 10:19 AM, Tsjerk Wassenaar <tsjerkw at gmail.com> wrote:

> Hi Brett,
>
> Let's say you're sitting at your _desk_ writing that paper with a deadline
> yesterday and you put a quick _meal_ next to you, wondering why on _earth_
> you keep up with this. Your hands are moving between the meal and the
> keyboard. You notice that the average position of your hands is somewhere
> between the two and mark the mean position on your desk. Then you draw a
> line through it that corresponds to the major extent of the motion of your
> hands, and write 'eigenvector 1' along it. You add a line through the
> average position, perfectly perpendicular to the first, and write
> 'eigenvector 2' along it. Now you can project every position of your hands
> onto your desk, giving it an 'eigenvector 1' coordinate (or score) and an
> 'eigenvector 2' coordinate (or score). You notice that it's only part of
> the total motion, as you neglect the height, which will be a third line,
> perpendicular to the desk.
>
> You can look at it a bit differently and say that your desk is the subspace
> of your real space, spanned by the two perpendicular vectors, which
> together describe most of your hand's motion.
>
> I hope this makes some sense :)
>
> Cheers,
>
> Tsjerk
>
>
>
>
>
> On Mon, Mar 9, 2015 at 2:33 AM, Brett <brettliu123 at 163.com> wrote:
>
> > Dear All,
> >
> > Recently I have read a gromacs related article which contain a sentence
> > "Trajectories pojected on the first two eigenvectors". Will you please
> tell
> > me the meaning of "eigenvector" and "Trajectories pojected on the first
> two
> > eigenvectors"? Will you please also explain it to me using common-used
> > words simple as desk, meal, earth, etc?
> >
> > Brett
> >
> >
> > --
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>
>
> --
> Tsjerk A. Wassenaar, Ph.D.
> --
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