some problem of solver in AMPL

[林立坤]

Dear friend,

I am sorry to bother you. Recently I met a question and I have no idea to deal with it. 

In my model, the objective is nonlinear and the decision variable is integral. At first I used the solver called KNITRO to solve the model, but the AMPL said: “a demo license is limited to 10 variables and 10 constraints and objectives. You have 148 variables, 78 constraints, and 1 objective. exit value 1.”

I do not know if there will be a way to solve my model directly. Could you please do me a favor to find a solver or some other ways to solve it?

    It will be a great pleasure to receive your reply. Thank you very much.

Best wishes

[ho.j...@gmail.com]

There is another solver called MINOS.  It can solve nonlinear problems and is also included in AMPL.  Give it a try!

[AMPL Google Group]

You downloaded a demo bundle, which is free but has restrictive limits on problem sizes. To try out solvers without those limits, you can consider the following options:

• Use an appropriate free open-source solver with AMPL's Community Edition, which has no problem size limit and does not expire.
• Request a free 30-day trial, which has no problem size limit and includes commercial solvers such as Knitro.
• Use the NEOS server to try unrestricted versions of AMPL and of many solvers that work with AMPL (including Knitro).

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Robert Fourer
am...@googlegroups.com

{#HS:1985736479-111537#}

On Sun, Aug 21, 2022 at 10:20 PM UTC, AMPL Modeling Language <am...@googlegroups.com> wrote:

There is another solver called MINOS. It can solve nonlinear problems and
is also included in AMPL. Give it a try!

[Michael Saunders]

Note that MInos is for linear and nonlinear problems with continuous variables.

It cannot enforce integer values on the variables.

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