Re: [Help-glpk] 'not' or 'or' constraints?

[François Galea]

Philip,

such 'or' constraints mean that your problem is neither a LP or a MIP.

In fact, if you have a single 'or' constraint, you can solve two 
independent problems, the first one with the first OR condition only, 
and the second with the second OR condition only. The optimal solution 
is the best of the optimal solutions in both problems.

Then, solving problems with a bigger amount of 'or' conditions would 
result in solving 2^n different problems, n being the number of 'or' 
conditions you have.

François


Philip Warner a écrit :
> This may not be the right forum for this, but I need to solve an LP 
> problem that is subject to constraints like:
>
>    s <= 0 OR s >= 100
>
> or, rewritten,
>
>    Not (0 < s < 100)
>
> Is this something I can do in GLPK?
>
>
>
> ----------------------------------------------------------------
> Philip Warner                    |     __---_____
> Albatross Consulting Pty. Ltd.   |----/       -  \
> (A.B.N. 75 008 659 498)          |          /(@)   ______---_
> Tel: (+61) 0500 83 82 81         |                 _________  \
> Fax: (+61) 03 5330 3172          |                 ___________ |
> Http://www.rhyme.com.au          |                /           \|
>                                  |    --________--
> PGP key available upon request,  |  /
> and from pgp.mit.edu:11371       |/
>
>
> _______________________________________________
> Help-glpk mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/help-glpk


--
François Galea
Laboratoire PRiSM
Université de Versailles-Saint Quentin en Yvelines
45 av Etats-Unis F-78035 Versailles CEDEX
Tél. : +33 1 39 25 40 50