Search found 15 matches
- Thu Oct 24, 2019 10:18 am
- Forum: Vensim
- Topic: Automatizing optimization
- Replies: 5
- Views: 3136
Re: Automatizing optimization
Thank you all for the answers!
- Wed Oct 23, 2019 1:50 pm
- Forum: Vensim
- Topic: Automatizing optimization
- Replies: 5
- Views: 3136
Automatizing optimization
Hello, I'm doing a policy optimization with VENSIM. My problem has many optima (as discussed here: https://www.ventanasystems.co.uk/forum/viewtopic.php?f=2&t=7218 ), so I use RRandom multiple start. When I track the "best payoff so far" on the screen, I see that it generally converges ...
- Tue Oct 15, 2019 12:13 pm
- Forum: Vensim
- Topic: Improving the modelling of annual decisions used for optimization
- Replies: 6
- Views: 3550
Re: Improving the modelling of annual decisions used for optimization
Thank you, it works now! I assume that if I use the same payoff definition file, replace the equation in my first message with an equivalent vector lookup function and update the optimization control file accordingly, I would have the same decisions for a policy optimization. Is it true as an assump...
- Mon Oct 14, 2019 3:11 pm
- Forum: Vensim
- Topic: Improving the modelling of annual decisions used for optimization
- Replies: 6
- Views: 3550
Re: Improving the modelling of annual decisions used for optimization
Hello, I try to model it with a vector lookup but I have this warning when I run the optimization. "timevalues" is a constant with a normal sub-type. No usable constant name. 0<=timevalues<=150. ^. Line 32 of file Opti_Control file_vector.VOC. Previous errors prevent continuing What should...
- Thu Oct 03, 2019 10:27 am
- Forum: Vensim
- Topic: Improving the modelling of annual decisions used for optimization
- Replies: 6
- Views: 3550
Improving the modelling of annual decisions used for optimization
Hello, I model a stylized electrcity market. My aim is to know the optimal investment decisions each year, by using Vensim optimization. To this end, I define the invesment variable as following, with a specific variable to use each year: IF THEN ELSE( Time=2020 ,g0 , IF THEN ELSE( Time=2021 ,g1 , I...
- Sat Jun 01, 2019 4:13 am
- Forum: Vensim
- Topic: Replicate optimization
- Replies: 14
- Views: 8976
Re: Replicate optimization
Thank you!
- Thu May 30, 2019 7:41 pm
- Forum: Vensim
- Topic: Replicate optimization
- Replies: 14
- Views: 8976
Re: Replicate optimization
Mostly applications.
- Thu May 30, 2019 7:05 pm
- Forum: Vensim
- Topic: Replicate optimization
- Replies: 14
- Views: 8976
Re: Replicate optimization
Is it possible for you to suggest me some exemplary papers that uses Vensim optimization ?
- Fri May 24, 2019 7:21 am
- Forum: Vensim
- Topic: Replicate optimization
- Replies: 14
- Views: 8976
Re: Replicate optimization
Yes, indeed I have many optima. I now try with rrandom multiple start but I guess I will never be sure of finding the global optimum.
I am using Powell optimizer. Do you think it is the right choice for my case (multiple optima)?
I am using Powell optimizer. Do you think it is the right choice for my case (multiple optima)?
- Wed May 22, 2019 11:25 am
- Forum: Vensim
- Topic: Replicate optimization
- Replies: 14
- Views: 8976
Re: Replicate optimization
I figured out that it was because of order of the parameters. The parameters were the same but the order was different.
- Wed May 22, 2019 9:03 am
- Forum: Vensim
- Topic: Replicate optimization
- Replies: 14
- Views: 8976
Re: Replicate optimization
Maybe it's because of the starting data. I'll check that. Thank you!
- Wed May 22, 2019 8:21 am
- Forum: Vensim
- Topic: Replicate optimization
- Replies: 14
- Views: 8976
Re: Replicate optimization
I use the same payoff function and same optimization parameters with the same min and max values. So I think that using the same Optimization control parameters, I should have exactly the same results. However, this is not the case. 1) Does the optimization output files contain the payoff function t...
- Wed May 22, 2019 7:26 am
- Forum: Vensim
- Topic: Replicate optimization
- Replies: 14
- Views: 8976
Replicate optimization
Hello,
Is there a reason why I cannot replicate the optimization results that I find with the .out file in the attachments?
Thank you.
Is there a reason why I cannot replicate the optimization results that I find with the .out file in the attachments?
Thank you.
- Fri May 03, 2019 1:36 pm
- Forum: Vensim
- Topic: How to obtain weights used in policy optimization?
- Replies: 6
- Views: 2922
Re: How to obtain weights used in policy optimization?
Thank you for the answers! @tomfid: Ensuring the sum of 1 would be my next question :) Thank you for the answer. The future in my model depends on delays and the subjects know about them. @Administrator: I am not sure I understand how to proceed. So I have annual decisions for 40 years from the expe...
- Thu May 02, 2019 2:52 pm
- Forum: Vensim
- Topic: How to obtain weights used in policy optimization?
- Replies: 6
- Views: 2922
How to obtain weights used in policy optimization?
Hello, I have a model in which there are two annual decisions for 40 years. There is a final target at the end of the simulation and there are three criteria to consider during the simulation. My payoff function is in the attachments. "Target reached at 2060?" is the final target. I change...