[Symphony] bicriteria operations

[Ted Ralphs]

Can you be a little more specific? Which examples are you working with
and how are you setting the coefficients? Can you send me a code
snippet to reproduce what you're seeing? One thing I can say is that
if all of the coefficients of the second objective are zero, it will
just invoke normal branch and bound.

Cheers,

Ted

On Fri, Apr 3, 2009 at 6:56 AM, S R <sr.pointe at gmail.com> wrote:
> I am trying to use the bicriteria optimization in symphony (version
> 5.2 or 5.1.10).  I am having trouble finding solutions and think I
> must be fundmentally misunderstanding things.
>
>
> After many attempts, here is what I think I have determined (examples from 5.2):
>
> -- Setting the second objective coefficients equal to the first
> objective coefficients, I am able to get a solution.
>
> -- Setting the second objective coefficients equal to a small ( x 10 )
> scalar multiple of the first objective coefficients, I am able to get
> a solution.
>
> -- Setting the second objective coefficients equal to a larger ( x 100
> ) scalar multiple of the first objective coefficients, I am NOT able
> to get a solution.
>
> -- Setting the second objective coefficients equal to 0, I am able to
> get a solution.  (Seems to use normal branch and bound.)
>
> -- Setting the second objective coefficients equal to 1, I am NOT able
> to get a solution.
>
> -- Setting the second objective coefficients to what I want them to
> actually be, the runtime is much longer and I am NOT able to get a
> solution.  I have not come up with any scalar multiplication of these
> coefficients that make any different.
>
>
> So, what am I missing?
>
> 1. Why do scalar multiplications make any difference?
>
> 2. How do I interpret the "Range: xxx to yyy" in the output?
>
> 3. Is there any documentation for this?  Or examples?
>
>
> Thanks for any assistance.
>
> Sam
>
> _______________________________________________
> Symphony mailing list
> Symphony at list.coin-or.org
> http://list.coin-or.org/mailman/listinfo/symphony
>



-- 
Dr. Ted Ralphs
Associate Professor, Lehigh University (permanent)
Visiting Professor, Monash University (current)
(610) 628-1280
ted 'at' lehigh 'dot' edu
coral.ie.lehigh.edu/~ted

Sent from Caulfield East, Victoria, Australia