Search found 373 matches
- 1 year ago
- Forum: Modeling
- Topic: GUSS Grid for parallizeable timeseries NLP
- Replies: 4
- Views: 1567
Re: GUSS Grid for parallizeable timeseries NLP
Hi Zamry, GUSS and the Grid Facility are two independent things that are used in combination in the gussgrid example you shared. In your case, it seems that the grid facility could be useful but given the model setup as you describe it, using GUSS will not be straightforward at all. So I suggest tha...
- 1 year ago
- Forum: Solvers
- Topic: Parallel Mode and Number of Threads Setting in cplex.opt file
- Replies: 3
- Views: 3070
Re: Parallel Mode and Number of Threads Setting in cplex.opt file
Looks correct. Please share your gms and log file. Fixing a problem with partial information is difficult.
Fred
Fred
- 1 year ago
- Forum: Modeling
- Topic: Need help with modelling . Topic : Mobile energy storage in distribution.
- Replies: 1
- Views: 948
Re: Need help with modelling . Topic : Mobile energy storage in distribution.
I doubt that you will find help this way. Your chances to get help will be much better if you follow the forum rules.
Fred
Fred
- 1 year ago
- Forum: Modeling
- Topic: Model generation time large compared to solving time
- Replies: 1
- Views: 931
Re: Model generation time large compared to solving time
Hi Simon, Half an hour model generation time for a model of that size is indeed incredibly long. Hard to say why it takes so long without being able to reproduce. Here we have some hints on how to implement models efficiently. If you could share the model/data, it might be easier for other forum use...
- 1 year ago
- Forum: Modeling
- Topic: Slow solution using MIP
- Replies: 6
- Views: 2503
Re: Slow solution using MIP
Hi, The McCarl Newsletter Volume 47 has a good introduction to model scaling and also gives some pointers to other places (like the GAMS documentation) where model scaling is discussed: https://www.gams.com/newsletter/mccarl/archive/mccarl_newsletter_no_47.pdf There are diffreent ways to detect wher...
- 1 year ago
- Forum: Syntax
- Topic: Error 71 Code
- Replies: 2
- Views: 1318
Re: Error 71 Code
Hi,
The error message actually says it all: You declare equation k888 in line 2571 but you never define it.
I hope this helps!
Fred
The error message actually says it all: You declare equation k888 in line 2571 but you never define it.
I hope this helps!
Fred
- 1 year ago
- Forum: Syntax
- Topic: Error 409 Code
- Replies: 2
- Views: 1264
Re: Error 409 Code
Hi,
You have to end the definition of each equation with a semicolon.
Best,
Fred
You have to end the definition of each equation with a semicolon.
Best,
Fred
- 1 year ago
- Forum: Modeling
- Topic: Slow solution using MIP
- Replies: 6
- Views: 2503
Re: Slow solution using MIP
Hi, Running with default settings (see Corre_iny_CON_Perdidas_baseline.log), the root relaxation already takes already 334 seconds on my machine. Afterwards, Cplex spends ages with the generation of flow cover cuts (I killed the job after half an hour). With that said, I tried to run the model with ...
- 1 year ago
- Forum: Syntax
- Topic: Re-solve model Fixing Variables
- Replies: 3
- Views: 3320
Re: Re-solve model Fixing Variables
Hi, Why do you want to solve the fixed MIP as an LP? If this is about the duals you would like to get for that fixed MIP, many solver links (e.g. GAMS/CPLEX) have a built-in option to solve the LP which you would get when fixing all discrete variables. For GAMS Cplex, this can be controlled via solv...
- 1 year ago
- Forum: Modeling
- Topic: GAMS Loops ends early
- Replies: 1
- Views: 1149
Re: GAMS Loops ends early
Hi,
hard to help without beiong able to reproduce. You loop over a set `iter`. So the loop will terminate after `card(iter)` iterations, no matter whether your termination criterion `abs(UB/LB) <= BdTol` is met.
I hope this helps!
Fred
hard to help without beiong able to reproduce. You loop over a set `iter`. So the loop will terminate after `card(iter)` iterations, no matter whether your termination criterion `abs(UB/LB) <= BdTol` is met.
I hope this helps!
Fred