GEKKO Result explanation

Question

would you mind sparing some time explaining why the Obj is zero here in some iterations?

tcstd and tdstd is min-max standardize of tc and td. I want to minimize tcstd*tdstd so the value of objective function should be 0-1. however during the process, the obj appears to be 0 but not define as optimal solution ? Thank you

Answer 1

The lines listed as zero objective are either non-integer solutions or non-feasible solutions. The lines with:

--Integer solution:

identify when the solver finds a candidate integer solution. The other lines are either successful (non-integer) with I:0

Iter :28 I: 0 Tm: 0.00 NLPi: 3 Dpth: 7 Lvs: 1 Obj: 0.00E00 Gap: 5.22E-0.2

or unsuccessful (I:<=-1) and therefore not candidate solutions with

Iter:29 I:-9 Tm :0.06 NLPi: 251 Dpth: 3 Lvs: 0 Obj: 7.36E-04 Gap: 5.15E-02

The final message is:

No additional trial points, returning the best integer solution 
Successful solution 

This says that there are no additional candidate solutions to try in the branch and bound approach. The best integer solution is returned.

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