[Ipopt] How to define a non-zero constraint?

[R Tavakoli]

as almost the same alternative: (a-b)(a+b)>0 and b>0

a comment: if you have only one constraint like  a!=0  there is a
more robust strategy: solve two distinct optimization problems, one with
constraint a>0 and one with constraints a<0 (you may replace 0 with a small
positive number you want), then the actual solution is the solution to one
of these problems with the least objective functional (benefit is the
convexity of constraint set in this way).



On Thu, Nov 11, 2010 at 9:33 AM, Lewis I <lewis369lewis at yahoo.com> wrote:

> Hello,
>
> I am try to define a non-zero constraint. i.e. a!=0
> I am trying to use:     a*a-0.000001>=0.
> where 0.000001 is the tolerance from zero.
> But I found the outcome was not so good.
> Do anyone has any ideas on modeling a non-zero constraint.
> Thank you so much
>
> Regards,
> Lewis
>
>
>
>
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