Ventana software support forum

Hey Tom, Thanks for the tips, I will correct the prior payoff as you recommend. Regarding the VOC file, I am sorry, I sent you the file already updated with your previous recommendation (log-transforming some of my parameters). So the range you see is Log (OW Density). I will run the MCMC now with t...

OK, thanks. I will try using log-transform. Also, I just emailed you the files of the model.

Thanks a lot for your rime

By the way: The convergence metrics with that odd-looking posterior sampling seem to be very good

Hi Tom, Thanks for your reply. This is an updated version of a model that I already shared with you in the past (Monarch Butterfly). It seems that the xlsx file with all my external data is too large to upload here. could you provide me with an email to send you that file please? And yes, it seems t...

Hi, I have been running a model through MCMC to obtain the posterior distribution of 7 parameters. The problem is that, if I set an upper and lower limit for the search range of the parameter, for example: 10<=Temperature<=50 the posterior seems to be getting 'artificially' oversampled in those limi...

Hey Tom, I already ran sims with and without annealing, and with and without the burn-in period, but I still see the same; as soon as the samples begin to get drawn, the stats move from an almost-ideal position to an awful one. I also made some runs with SA and making sure that temp goes down to 1 b...

Hi Tom, I followed all your recommendations and things are starting to look considerably better. However, there is a very odd problem that I cannot wrap my head around and it is impeding me to get my posterior samples. The thing is that the Acceptance Rate, Max PSRF, and CMCP are right on their idea...

Thank you so much Tom. That makes a lot of sense!.

Hopefully, this will make everything run soft and smooth.

I hope you don't mind if I get back in touch with you if I come with any problems (hopefully not)

Thanks and stay safe!

Excelllent, I'll do that.

I am not sure why the files didn't get attached

Here they are again

Thanks!

Hi Tom, Thank you so much for your reply. I checked the reading that you suggested to me over the FB page (Optimization and the Banana of Death) which gave me the idea of trying to use simulated annealing. I just started the sims 30 mins ago but it seems that it is moving in the right direction. I t...

Hello everyone, I hope you are doing fine and safe. I am working with a VENSIM model of the Monarch Butterfly and want to get the uncertainty of 6 estimated parms in the model using MCMC posterior sampling. This is the first time that I use VENSIM's MCMC and I am having trouble reaching convergence....

Excellent. thank you so much. I am looking forward to your input. Meanwhile, I'll run it as is and will share my posteriors once it is done. Thanks!

Thanks a lot for your answer Tom, and no worries at all about the delay! I really appreciate your response. Based on your reply here and the Weibull model that you replied in this thread https://www.ventanasystems.co.uk/forum/viewtopic.php?f=2&t=5428&p=20730&hilit=mcmc#p20730 , I added a...

Hi, hopefully, someone can answer this question soon

Hi, I am just starting to explore the MCMC options in VENSIM, but I have several questions and hopefully, I can get some help here: 1.- How to input priors? I just don't see where I can specify the distribution of my priors. I am supposing that, by using the search limits in the optimization options...

Hi Tom, I explored a lot of avenues on how to dynamically coupling R with VENSIM, but I couldn't find the way. I am sure there's a way, but maybe my limited programming knowledge is not helping. A good thing is that I noticed that I can do exactly what I wanted to do from within VENSIM without the n...

Sounds good. I'll get to work on that and report back on Monday. Thanks!

Yes, R has the dyn.load ( ) function in R can Load or unload DLLs. So, would I have to convert my Vensim.mdl into a DLL and then directly running it from VENSIM? Sorry for the naive questions, I've never used the DLL functionality in Vensim and I am not familiarized at all on how all that works

Hi, I'm trying to find a way of coupling R with VENSIM so I can run a Bayes Sampler in R, run a simulation in VENSIM, and return the Payoff to R for the next round of Bayes Sampling. In theory, I could generate a CIN file from R--> run VENSIM with that CIN file generated --> export results from simu...

Hi, I need to analyze my results using Standard Deviates, i.e. subtract the observed population growth rate from the mean projected population growth rate and dividing by the standard deviation of the projected growth rate (McCarthy et al., 2001). For doing so, I want to export the sensitivity run (...

A little textbox on the status bar or somewhere else, showing the errors, payoff, etc, without popping out a whole window (it is quite annoying having to almost-automatically close the payoff pop-out window everytime I run a simulation)

Hello everyone!, I really like the suggestions that are being put forward, and totally agree with them. Here are my two cents: Being able to: -Take the results from optimization and load them permanently in the model (not just with Load changes from) -To independently turn on and off the graphs of e...