Hi all,
I there anyway to linearize a logarithmic function (log) defined over a variable in GAMS?
Thank you for your help.
Search found 10 matches
- 1 month ago
- Forum: Modeling
- Topic: linearization of a logarithmic function (log) defined over a variable
- Replies: 1
- Views: 172
- 4 months ago
- Forum: Modeling
- Topic: "Couenne finished. No feasible point found."
- Replies: 0
- Views: 473
"Couenne finished. No feasible point found."
Hi all, I am trying to run an MINLP model with Couenne . But I keep getting this message that "Couenne finished. No feasible point found." Model solve summary also reports RESOURCE INTERUPT and 14 NO SOULTION FOUND. However, I am able to find some locally optimum solution using Dicopt. Does it mean ...
- 6 months ago
- Forum: Modeling
- Topic: Problem with loop in MINLP model.
- Replies: 1
- Views: 312
Problem with loop in MINLP model.
Hi all, I have a MINLP model which I try to do sensitivity analysis in a loop. I set the starting point into the loop. Now I have a problem that the results that I get using the loop are different from the results of corresponding scenario but without a loop. For example, some times the model with t...
- 7 months ago
- Forum: Modeling
- Topic: How to use loop to run model several times when some random data is being imported from excel.
- Replies: 2
- Views: 384
Re: How to use loop to run model several times when some random data is being imported from excel.
Hi Renger,
Thank you very much for your help.
Best,
Mary
Thank you very much for your help.
Best,
Mary
- 7 months ago
- Forum: Modeling
- Topic: How to use loop to run model several times when some random data is being imported from excel.
- Replies: 2
- Views: 384
How to use loop to run model several times when some random data is being imported from excel.
Hi All, I import some random data from excel into GAMS. So every time that I run the model the results change because the random numbers change. I'd like to use a loop to rum the model several times by that loop rather than running manually. I would appreciate it if anyone can help me. Sorry if the ...
- 7 months ago
- Forum: Syntax
- Topic: logical equations & binary variables
- Replies: 18
- Views: 3301
Re: logical equations & binary variables
Hi again Manassaldi, I have a new question for you and will really appreciate it if you can help me as before. I am still struggling with these kind of logical conditions on endogenous variable in my model. The problem is that p(n) includes a binary variable itself. I mean p(n) = sum(g, t(g) * c(g,n...
- 7 months ago
- Forum: Solvers
- Topic: Couenne solver error: " Equation 47 is general nonlinear: function vcPower results in a nonlinear expression"
- Replies: 1
- Views: 382
Couenne solver error: " Equation 47 is general nonlinear: function vcPower results in a nonlinear expression"
Hi all, I have a MINLP model and am using Couenne solver. The solver gives me some errors. The error message are: " Equation 47 is general nonlinear: function vcPower results in a nonlinear expression". From this error message I have no clue what is the reason of the problem. Can anyone help me on t...
- 7 months ago
- Forum: Modeling
- Topic: Nonlinear constraints in MINLP model
- Replies: 2
- Views: 357
Nonlinear constraints in MINLP model
Hi all, I have a mixed integer non linear model and now I am trying to reduce the number of nonlinear constraints because the model is very big and I keep getting infeasibilities or errors. Two of the constraints that are non linear are as following: const11(n).. p(n) =e= 1 - (1 + (d(n) / 229)) ** (...
- 8 months ago
- Forum: Syntax
- Topic: logical equations & binary variables
- Replies: 18
- Views: 3301
Re: logical equations & binary variables
Hi Manassaldi.
Thank you so much for helping me out. Your analysis was really helpful.
Best,
Mary
Thank you so much for helping me out. Your analysis was really helpful.
Best,
Mary
- 8 months ago
- Forum: Syntax
- Topic: logical equations & binary variables
- Replies: 18
- Views: 3301
Re: logical equations & binary variables
Hi all, I have a question regarding logical conditions applied to choice variables. I will be happy if someone, specially Manassaldi, can help me on that. I have two choice variables, a(n) and th, and a parameter p(n). I need to code the following logic in gams. if p(n)<= th then a(n) =0; else if th...