Search found 502 matches

by bussieck
2 days ago
Forum: Bugs
Topic: MSNLP solver "stops" before running the algorithm
Replies: 3
Views: 97

Re: MSNLP solver "stops" before running the algorithm

My bet is on Ipopt as the culprit. You could use the solver as an executable (add solvelink 2 to the msnlp.opt) and observe what process hangs. Moreover, it makes much more sense to use an active set solver like Conopt within MSNLP. MINLP is about restarts and an interior code (like Ipopt) and resta...
by bussieck
1 week ago
Forum: Tools
Topic: Make a noise in GAMS
Replies: 2
Views: 229

Re: Make a noise in GAMS

Never heard a request like this before... GAMS does not make noises but you can execute any program with execute. Here is a way to play a wav file (on Windows): ... solve mymodel us lp min z; execute 'powershell -c (New-Object Media.SoundPlayer "C:\Windows\Media\notify.wav").PlaySync();' -Michael
by bussieck
1 week ago
Forum: Syntax
Topic: Data exchange: $gdxin works but execute_load fails
Replies: 1
Views: 124

Re: Data exchange: $gdxin works but execute_load fails

Understand the difference between compile time and execution time (https://www.gams.com/32/docs/UG_GamsCall.html#UG_GamsCall_TwoPass). GAMS cannot extend the universe of labels (set elements) at run time. All labels must be known at the end of compilation. Your program has no labels and hence execut...
by bussieck
3 weeks ago
Forum: Modeling
Topic: How to interpret BARON solutions
Replies: 2
Views: 212

Re: How to interpret BARON solutions

Branch and bound methods (as implemented in Baron) work with a relaxation ("Best possible") and an incumbent ("Solution"). If the difference (absolute ("Absolute gap") and relative ("Relative gap")) between the two is 0 then your incumbent is the optimal solution. Since you have the tolerance for th...
by bussieck
3 weeks ago
Forum: Solvers
Topic: Use option memnodes to reset to > 10000.
Replies: 7
Views: 333

Re: Use option memnodes to reset to > 10000.

The model does not help. I won't occupy my machine for >2h to get to your feasible point. You can save a solution into a GDX file (and share that) via the savepoint option and share this.

-Michael
by bussieck
3 weeks ago
Forum: Modeling
Topic: Looping over objective function possible?
Replies: 2
Views: 159

Re: Looping over objective function possible?

You can loop in GAMS. Lets say you want to solve your model over and over again with values for parameter p from 1 to 3 in steps of 0.1, the following code does that: ... set ps / p1*p30 /; parameter objrep(ps); loop(ps, p = 1 + (ord(ps)-1)/10; solve mymodel min z us lp; objrep(ps) = z.l; ); ... -Mi...
by bussieck
3 weeks ago
Forum: Solvers
Topic: Use option memnodes to reset to > 10000.
Replies: 7
Views: 333

Re: Use option memnodes to reset to > 10000.

From what you sent (an lst file) it is hard to verify the solution reported by SBB. I see no obvious reason why qe(0) should be 69.975. There are multiple ways to verify that a solver reports a solution correctly, e.g. Examiner (https://www.gams.com/latest/docs/S_EXAMINER.html) or just solve a secon...
by bussieck
3 weeks ago
Forum: Solvers
Topic: Use option memnodes to reset to > 10000.
Replies: 7
Views: 333

Re: Use option memnodes to reset to > 10000.

I have no idea what you are asking about. BTW, the model is an MIQCP and can be solved to global optimality in seconds by various global solvers, e.g. SCIP (see attached log).
enerji 90.log
(9.5 KiB) Downloaded 15 times
-Michael
by bussieck
3 weeks ago
Forum: Contributed Documentation and Tools
Topic: GAMS-L mailing list
Replies: 0
Views: 297

GAMS-L mailing list

There is an older alternative to this forum and there are still a couple of active users out there (mostly users from the economic modeling community). Here is a bit information about the mailing list: There are two possible ways to subscribe: Use a web interface to join and leave the list and to br...
by bussieck
3 weeks ago
Forum: Solvers
Topic: Use option memnodes to reset to > 10000.
Replies: 7
Views: 333

Re: Use option memnodes to reset to > 10000.

You need to create an SBB option file (as documented here https://www.gams.com/latest/docs/UG_SolverUsage.html#BASIC_USAGE_SOLVER_OPTION_FILE). You can create this file even from within GAMS in various ways, e.g. $onecho > sbb.opt memnodes 1e6 $offecho mymodel.optfile = 1; option minlp=sbb; solve my...