User GAMS,

I have GAMS version 22.7.2 and version 23.8.2. I run my code in both

version and I have different answers(objective Value). I am using the

same solver in both cases CONOPT. I was wondering why I got different

answer If I am using the same solver?. I got better values (more

logical) using version 22.7.2. So what is the main difference between

these versions CONOPT version 3.14S and version 3.15D?

I’ll appreciate any feedback.

Omar Alminagorta

Ph.D Candidate

Utah State University

/////////// Version 22.7.2

S O L V E S U M M A R Y

MODEL Nov30 OBJECTIVE Obj

TYPE RMINLP DIRECTION MAXIMIZE

SOLVER CONOPT FROM LINE 1027

**** SOLVER STATUS 1 NORMAL COMPLETION

**** MODEL STATUS 2 LOCALLY OPTIMAL

**** OBJECTIVE VALUE 379902341.3100

RESOURCE USAGE, LIMIT 269.258 1000.000

ITERATION COUNT, LIMIT 5341 10000

EVALUATION ERRORS 0 0

C O N O P T 3 version 3.14S

Copyright (C) ARKI Consulting and Development A/S

Bagsvaerdvej 246 A

DK-2880 Bagsvaerd, Denmark

Using default options.

The model has 8149 variables and 11235 constraints

with 24189 Jacobian elements, 4750 of which are nonlinear.

The Hessian of the Lagrangian has 1500 elements on the diagonal,

1750 elements below the diagonal, and 2400 nonlinear variables.

** Optimal solution. Reduced gradient less than tolerance.

//////////////////////// version 23.8.2

S O L V E S U M M A R Y

MODEL Nov30 OBJECTIVE Obj

TYPE RMINLP DIRECTION MAXIMIZE

SOLVER CONOPT FROM LINE 1027

**** SOLVER STATUS 1 Normal Completion

**** MODEL STATUS 2 Locally Optimal

**** OBJECTIVE VALUE 422962605.3883

RESOURCE USAGE, LIMIT 547.548 1000.000

ITERATION COUNT, LIMIT 5442 10000

EVALUATION ERRORS 0 0

CONOPT 3 Mar 17, 2012 23.8.2 WEX 31442.32372 WEI x86_64/MS

Windows

C O N O P T 3 version 3.15D

Copyright (C) ARKI Consulting and Development A/S

Bagsvaerdvej 246 A

DK-2880 Bagsvaerd, Denmark

The model has 8149 variables and 11235 constraints

with 24189 Jacobian elements, 4750 of which are nonlinear.

The Hessian of the Lagrangian has 1500 elements on the diagonal,

1750 elements below the diagonal, and 2400 nonlinear variables.

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