Dear GAMS-community,

i met a new GAMS problem in my powerplant-model that i cannot solve on

my own - but maybe with your help:

I try to build an equation, which sums up a number of power outputs “P

(i,j)”, depending on the power plant “i” and the time step “j”. The

sum of this power outputs should be equal to the load “L(j)” which has

to be covered in time step “j”.

The problem is that I only want to sum up those power outputs “P

(i,j)”, which are higher than the given value “Pmin(i)” of each power

plant.

I tried to write this in the following way:

LoadCover(j)… sum(i,P(i,j)$(P(i,j) >= Pmin(i))) =e= L(j)

The mip-solver gives two error-messages:

Error 57: Endogenous relational operations require model type “dnlp”

But the “dnlp” model type is not recommended in the GAMS manual and

moreover it would make me changing all the other equations.

Error 256: Error(s) in analyzing the solve statement.

Does anybody have an idea how i can draft my equation differently?

Thanks in advance,

Tobias

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operator can be used for conditional statements but GAMS compiler
encounters an error if we use in equation definitions! In fact, if

you change NLP to DNLP , “Error 53: Endogenous $ operation not

allowed” will appear! So, maybe you can define LoadCover in

conditional statement before equation part!

On Aug 11, 11:15 am, tobster wrote:

Dear GAMS-community,

i met a new GAMS problem in my powerplant-model that i cannot solve on

my own - but maybe with your help:

I try to build an equation, which sums up a number of power outputs “P

(i,j)”, depending on the power plant “i” and the time step “j”. The

sum of this power outputs should be equal to the load “L(j)” which has

to be covered in time step “j”.

The problem is that I only want to sum up those power outputs “P

(i,j)”, which are higher than the given value “Pmin(i)” of each power

plant.

I tried to write this in the following way:

LoadCover(j)… sum(i,P(i,j)$(P(i,j) >= Pmin(i))) =e= L(j)

The mip-solver gives two error-messages:

Error 57: Endogenous relational operations require model type “dnlp”

But the “dnlp” model type is not recommended in the GAMS manual and

moreover it would make me changing all the other equations.

Error 256: Error(s) in analyzing the solve statement.

Does anybody have an idea how i can draft my equation differently?

Thanks in advance,

Tobias

–~–~---------~–~----~------------~-------~–~----~

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

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