NLP - infeasibility

GAMS
1

Hello:

One of my equations, in NLP, has the following expression:

SET
q

EQUATIONS
Cost = A + [B/{C(q)*D(q)}]

For some elements in the set q, C(q) and D(q) are zeroes.
This creates the error - DIVISION BY ZERO
how to correct it? The manual suggested to use the optional
commands .LO or .L

If I use the optional command, C(q).LO = 1, then the final optimal
solution will have C(q) = 1.

If I use the optional command, C(q).L = 1, then only the starting
values are set to 1. It can be anything other than zero in the final
solution.

Am I correct in interpreting these two optional commands?
Which one should I use?

Thanks.

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2

Hello.

I used $(C(q) gt 0) condition and it worked…

I would like other ways that can solve similar DIVISION BY ZERO error.
Thanks

\

3

Hi there,
you can put a lower limit as you did but with the .LO option e.g.:
C(q).lo=epsilon (a small number)

or you can redefine the cost equation adding the epsilon parameter:

Cost = A + [B/{C(q)*D(q)+epsilon}]

Hope this help

Best Regards

2010/6/10 whoami

Hello.

I used $(C(q) gt 0) condition and it worked…

I would like other ways that can solve similar DIVISION BY ZERO error.
Thanks

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Daniel Andrés Navia López
Ingeniero Civil Químico
Mg.Sc.Ciencias de la Ingeniería, Mención Ingeniería Química
Máster en Investigación en Ingeniería de Procesos y Sistemas
626752875

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