Hi there,

I’m trying to solve a bi-level model directly with the EMP GAMS functionality, but I’m getting the following error multiples times in the *.lst file:

“JAMS Equation XXX dual column will be empty. Abort!

*** JAMS Equation XXX contains only variables being part of DualVar mappings”

The model is quite long, but the basic idea is to solve a bi-level problem in which the upper level problem will use some of the dual variables of the lower level problem in the objective. The form is:

min upper_objective =E= f(lower_level_vars,lambda)

subject to {upper_level_constraints}

min lower_objective =E= g(lower_level_vars,upper_level_vars)

{lower_level_constraints} - lambda

I’ve created the emp.info file using the following structure:

$onecho “%emp.info%”

Bilevel upper_objective {upper_level_vars}

MIN lower_objective * {lower_level_constraints}

Dualvar lambda constraint

$offecho

Any idea of what is going on?

Best regards,

Ángel Paredes.

P.S.: It’s my first topic, but I’ve been following this forum during a couple of years, thanks for all the help.