[Iccrg] Re: [Tmrg] convergence time

[Lachlan Andrew]

Greetings Dirceu,

On 31/10/2007, Dirceu Cavendish <dirceu_cavendish at yahoo.com> wrote:
> I find transient interaction effects VERY interesting to study...

True.  But they are also complex.  My aim with this roundtable was to
agree on some simple "single numbers" to make comparison between
different people's experiments easier.  If we measure convergence time
as the time for  X(t)  to reach within 20% of its final value, but in
the experiment,  X(t)  never reaches its final value, then we are left
with no numeric measure of the convergence time.

What information will  X(t)  tell us about the interactions that isn't
more apparent from  x(t)?  The benefits David mentioned apply mainly
to the case without interactions.

> The bottom line is: agreeing on X(t) performance metrics instead of x(t)
> does not LIMIT in any way the expressiveness of experimental results, since
> we can always reduce X(t) to x(t) by using a single flow...

I agree that we can get  x(t)  from  X(t)  by differentiating it
(regardless of how many flows).
In terms of "expressiveness", they both carry exactly the same amount
of information, if we want to compare the whole functions, rather than
thresholding thiem.  My question is how we can make that comparison.
Does anyone have any suggestions?

To me, we need to agree on some sort of data reduction, and
thresholding is a simple example.  Thresholding  X(t)  seems more
problematic.  Of course, that problem may go away if there is a better
alternative than thresholding.

Thanks,
Lachlan

-- 
Lachlan Andrew  Dept of Computer Science, Caltech
1200 E California Blvd, Mail Code 256-80, Pasadena CA 91125, USA
Ph: +1 (626) 395-8820    Fax: +1 (626) 568-3603
http://netlab.caltech.edu/~lachlan