[AMPL 2578] Re: Assignment and constraints

[x-22]

Sorry, that was a typo. No indexing in the objective function. Just minimize "final" which is defined under "c".

Thank you!

> From: x <to_rent_2000@...>
> Subject: Assignment and constraints
> To: ampl@...
> Date: Thursday, June 4, 2009, 2:15 PM
> Hi all,
>
> I have the following. I'm keeping the syntax simple here
> for ease of discussion.
>
> var L{0..4}, M{0..4};
> var final >= 0;
>
> c1{j in 0..4}: L[j] <= M[j];
>
> c2{j in 1..4}: L[j] = L[0];
>
> c{j in 0..4}: final = sum{j} (M[j] - L[j]);
>
> minimize{j in 0..4}: final;
>
> #need this explicitly?
> #c3{j in 0..4}: L[0] <= M[j];
>
> This crashes FilMINT solver. Unfortunately, I don't get any
> indication of what or where the problem is when the solver
> crashes.. So, I tried it with MINOS solver; it ignores
> integrality (not related to the variables shown here) but
> solves the problem. However, it picks L[0] to have a value
> that is not <= each M[j] which makes final negative. But
> this is not what I expected.
>
> So, my question is this - when L[1..4] is assigned L[0],
> will L[0] value be selected by the solver to be <= each
> of the M[j] per constraint c1?
>
> [Or, does the solver pick L[0] <= M[0], assign L[0] to
> the rest of the L[j] and then crash if c1 or final_LB is
> violated? In that case, I'd have to include c3 constraint
> but even that hasn't helped me with FilMINT so far. However,
> me forcing L[0] to have a valid value (through a constraint)
> helps..]
>
> Sincere thanks in advance for any and all information!

--- On Thu, 6/4/09, Stefano Coniglio <stefano.coniglio@...> wrote:

> From: Stefano Coniglio <stefano.coniglio@...>
> Subject: [AMPL 2577] Re: Assignment and constraints
> To: "AMPL Modeling Language" <ampl@...>
> Date: Thursday, June 4, 2009, 7:43 PM
>
> > minimize{j in 0..4}: final;
>
> With this declaration you have 5 objective functions. Which
> one are
> you minimizing?
>
> >
>

     

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