Search found 66 matches
- 5 years ago
- Forum: Modeling
- Topic: Iterative models/ Dynamic sets
- Replies: 10
- Views: 11229
Re: Iterative models/ Dynamic sets
Hi all, I have a similar problem. I want to solve a model interatively. In my model I have two sets: t (for time) and households. Most of my parameters depend on both sets(t,households) and some only on (households) like: ... demand_electrical(t, household) $LOAD demand_electrical volumeOfBufferTank...
- 5 years ago
- Forum: Syntax
- Topic: Objective with if-condition
- Replies: 28
- Views: 21746
Re: Objective with if-condition
Thanks Fred for your answer, it solves my problem.
- 5 years ago
- Forum: Syntax
- Topic: Objective with if-condition
- Replies: 28
- Views: 21746
Re: Objective with if-condition
Thanks for your answer Fred, now I understand my mistake but I do not know how to fix it. How can the variable x depend on y? I tried SOS1 variable x(t, household,y) heatGenerationForBufferTank; SOS1 variable y(t, household,x) heatGenerationForDHWTank; but it did not work because y and x are not set...
- 5 years ago
- Forum: Syntax
- Topic: Objective with if-condition
- Replies: 28
- Views: 21746
Re: Objective with if-condition
Thanks Fred for your answer, I changed the variables Binary variable x(t, household) heatGenerationForBufferTank; Binary variable y(t, household) heatGenerationForDHWTank; to SOS1 variable x(t, household) heatGenerationForBufferTank; SOS1 variable y(t, household) heatGenerationForDHWTank; and it see...
- 5 years ago
- Forum: Syntax
- Topic: Objective with if-condition
- Replies: 28
- Views: 21746
Re: Objective with if-condition
Hi guys, it's me again having a slightly different question as the one posted before but it has also something to do with modelling if conditions: I now have two variables x and y that with the following constraings: x + y <= 1 x + y >= 0.1 if x > 0 --> y =0 if y > 0 --> x =0 0<=x<=1 0<=y<=1 How can...
- 5 years ago
- Forum: Solvers
- Topic: MIP Start with CPLEX from a file
- Replies: 26
- Views: 26316
Re: MIP Start with CPLEX from a file
Thanks Fred for your answer, GAMS/CPLEX does not distinguish between a default 0 and an explicitly set 0. Hence, during Mipstart those zero levels are considered to be fixed as well which might be the reason that your mipstart is not accepted. But when I just use this one feasible solution I also do...
- 5 years ago
- Forum: Solvers
- Topic: MIP Start with CPLEX from a file
- Replies: 26
- Views: 26316
Re: MIP Start with CPLEX from a file
Thanks cladelpino for your answer, So, running with fixed variables finishes in "optimal solution" ? Are you initializing all variables in your problem ? Well GAMS says that it is an optimal solution (but of course this is not an optimal solution; it is just a feasible solution that I gene...
- 5 years ago
- Forum: Solvers
- Topic: MIP Start with CPLEX from a file
- Replies: 26
- Views: 26316
Re: MIP Start with CPLEX from a file
Thanks Fred for your answer and your help, now I got a feasible solution which I tested by x.fx(t, household) = x_Initial(t, household); y.fx(t, household) = y_Initial(t, household); So this solution is feasible and GAMS also accepts this solution. However when I want to do a MIP start with this sol...
- 5 years ago
- Forum: Syntax
- Topic: Objective with if-condition
- Replies: 28
- Views: 21746
Re: Objective with if-condition
Thanks cladelpino for your answer,
I think (and hope) that I have understood it now
I think (and hope) that I have understood it now
- 5 years ago
- Forum: Solvers
- Topic: MIP Start with CPLEX from a file
- Replies: 26
- Views: 26316
Re: MIP Start with CPLEX from a file
Hi, it's me again having a question regarding a MIP start (sorry to bother you with my questions but I do not have that much experience with GAMS and I have no one to ask except this forum; I am really thankful for your help and appreciate it). I have a solution which I think is feasible. To check t...