Multi Solve Problem

GAMS
1

Dear all,

I try to write model by using multi solve. I want to use an achieved
variable from first solve in the second solve. Following is the final
part of my model. But the gams compiler does not distinguish and
consider zero as default amount. I do not know what to write. Would
you please let me know any solution?

Thank you,

Lendi

MODEL MAX_COST /OBJ1, NAC1, NAC2, ET1, ET2 /
MIN_COST /OBJ2, DP1, DP2, RRP1, RRP2/;
*
*
*Specify Objective Function of First Part
*
*
SOLVE MAX_COST MAXIMIZING C USING NLP;
*
*
*Specify Objective Function of Second Part
*
*
SOLVE MIN_COST MINIMIZING CP USING NLP;

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2

Lendi,

So you get 0 as the objective of the minimization run and 0 as the
objective of the maximization run. That can have different reasons:

  1. all feasible points have objective value 0

but more likely,

  1. the input point of your NLP is a stationary point. Local NLP
    solvers like CONOPT or MINOS are stuck in this point.

Try setting a better starting point (by setting the .l values of your
varibales), or try a global solver (Baron, LindoGlobal, Lgo, MSNLP,
OQNLP).

Hope this helps,
Michael Bussieck - GAMSWorld Coordinator

On Aug 18, 6:41 pm, Lenlendi wrote:

Dear all,

I try to write model by using multi solve. I want to use an achieved
variable from first solve in the second solve. Following is the final
part of my model. But the gams compiler does not distinguish and
consider zero as default amount. I do not know what to write. Would
you please let me know any solution?

Thank you,

Lendi

MODEL MAX_COST /OBJ1, NAC1, NAC2, ET1, ET2 /
MIN_COST /OBJ2, DP1, DP2, RRP1, RRP2/;
*
*
*Specify Objective Function of First Part
*
*
SOLVE MAX_COST MAXIMIZING C USING NLP;
*
*
*Specify Objective Function of Second Part
*
*
SOLVE MIN_COST MINIMIZING CP USING NLP;

–~–~---------~–~----~------------~-------~–~----~
To post to this group, send email to gamsworld@googlegroups.com
To unsubscribe from this group, send email to gamsworld+unsubscribe@googlegroups.com
For more options, visit this group at http://groups.google.com/group/gamsworld?hl=en
-~----------~----~----~----~------~----~------~–~—

\