Search found 273 matches

by bussieck
28 minutes ago
Forum: Modeling
Topic: power system scheduling
Replies: 1
Views: 6

Re: power system scheduling

Eventually, any continuous distribution is discretized before solving the stochastic optimization model. You can do this in the GAMS code and set up a discrete distribution then you can use e.g. DE with Cplex or you let Lindo do it internally and then you need to use Lindo's algorithms.

-Michael
by bussieck
3 hours ago
Forum: Syntax
Topic: Error 171: Domain violation for set
Replies: 1
Views: 4

Re: Error 171: Domain violation for set

If you want to use GAMS at a dissertation level, you need to invest more in learning the tool. Your errors are of very fundamental nature: 1. You need to make some sets subsets of i adn j: itoj(i) 'arriving train units to be assigned to departing train units'/i7,i17,i27/ jtoi(j) 'departing train uni...
by bussieck
4 days ago
Forum: Modeling
Topic: DICE2016. Damage function and Limit scenarios
Replies: 3
Views: 68

Re: DICE2016. Damage function and Limit scenarios

Sorry, I don't understand enough about the DICE model to be of any help. DAMFRAC suggest some value between 0 and 1. If I take the original definition the values of DAMFRAC in the optimal solution are in this range: ---- VAR DAMFRAC Damages as fraction of gross output LOWER LEVEL UPPER MARGINAL 1 -I...
by bussieck
5 days ago
Forum: Modeling
Topic: DICE2016. Damage function and Limit scenarios
Replies: 3
Views: 68

Re: DICE2016. Damage function and Limit scenarios

Don't look at the solution before you look at the solution status. It seems that your model is infeasible and therefore the variable values reported back to GAMS are no solution.

-Michael
by bussieck
1 week ago
Forum: Announcements
Topic: GAMS Distribution 27.0.0 (Beta Release)
Replies: 0
Views: 125

GAMS Distribution 27.0.0 (Beta Release)

Hi GAMS Users, We would like to announce the availability of the GAMS Beta Release 27.0.0. Please consult the beta release notes for details about new features and updated solvers: https://www.gams.com/beta/docs/RN_27.html If you are interested in experimenting with this beta release, please downloa...
by bussieck
1 month ago
Forum: Modeling
Topic: How to display decision variables in AUGMECON2?
Replies: 4
Views: 131

Re: How to display decision variables in AUGMECON2?

Since you don't worry about sorting and uniqueness of the solutions why not just print the level of the variables you are interested in right in the txt file: else put iter:5:0; loop(k, put z.l(k):12:2;); jump(km1) = 1; * find the first off max (obj function that hasn't reach the final grid point). ...
by bussieck
1 month ago
Forum: Modeling
Topic: How to display decision variables in AUGMECON2?
Replies: 4
Views: 131

Re: How to display decision variables in AUGMECON2?

I actually rework the example for our model library. I have attached the new version that uses a different way of save the GDX point file and used embedded code to get the sorted and unique list of points. This requires a recent version of GAMS.

-Michael
by bussieck
1 month ago
Forum: Modeling
Topic: help me set up a model
Replies: 8
Views: 259

Re: help me set up a model

If I knew how to do this I would be raking in money by selling superior MIP solvers. You need to invest to learn about optimization and see if you can do something smart for your particular situation/model. There are no shortcuts.

-Michael
by bussieck
1 month ago
Forum: Modeling
Topic: How to display decision variables in AUGMECON2?
Replies: 4
Views: 131

Re: How to display decision variables in AUGMECON2?

That's a little tricky. The model uses a put file to record all solutions it found and then uses some external tools (sort and uniq) to only report the unique solutions (with respect the the objective functions). One could use the savepoint facility to export each solution to a GDX file and rename (...
by bussieck
1 month ago
Forum: Modeling
Topic: Optimal Power Flow of larger power system.
Replies: 1
Views: 64

Re: Optimal Power Flow of larger power system.

Hi, as I said in topic "GAMS for larger systems" (https://forum.gamsworld.org/viewtopic.php?t=10775#p25129) : Without seeing the code it's hard to tell if you can improve this or not. Hope you can share the model and data. If you don't want to make model and data public in the forum you can still su...