Search found 55 matches

by PeterBe
1 day ago
Forum: Syntax
Topic: Objective with if-condition
Replies: 28
Views: 829

Re: Objective with if-condition

Thanks Fred for your answer, it solves my problem.
by PeterBe
2 days ago
Forum: Syntax
Topic: Objective with if-condition
Replies: 28
Views: 829

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...
by PeterBe
3 days ago
Forum: Syntax
Topic: Objective with if-condition
Replies: 28
Views: 829

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...
by PeterBe
5 days ago
Forum: Syntax
Topic: Objective with if-condition
Replies: 28
Views: 829

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...
by PeterBe
2 weeks ago
Forum: Solvers
Topic: MIP Start with CPLEX from a file
Replies: 23
Views: 647

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...
by PeterBe
2 weeks ago
Forum: Solvers
Topic: MIP Start with CPLEX from a file
Replies: 23
Views: 647

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 generated usin...
by PeterBe
2 weeks ago
Forum: Solvers
Topic: MIP Start with CPLEX from a file
Replies: 23
Views: 647

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...
by PeterBe
2 weeks ago
Forum: Syntax
Topic: Objective with if-condition
Replies: 28
Views: 829

Re: Objective with if-condition

Thanks cladelpino for your answer,

I think (and hope) that I have understood it now :D
by PeterBe
2 weeks ago
Forum: Solvers
Topic: MIP Start with CPLEX from a file
Replies: 23
Views: 647

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...
by PeterBe
3 weeks ago
Forum: Syntax
Topic: Objective with if-condition
Replies: 28
Views: 829

Re: Objective with if-condition

Thanks cladelpino for your answer, you wrote This is a very common misconception. The sooner you forget about it, the better your path in optimization will be. There is no difference between one type of equality constraint or the other, neither is the problem solved sequentially. The best model to r...