Ventana software support forum

Hi Tom, and thank you very much for your feedback and models!! :D The behaviour that I was looking for is already there in the first model that you shared! It's the 'previous pulse height' stock! If you double check the second model, you will notice that the behaviour of all three stocks is the same...

Hi tomfid, and thank you for your answer and model! You are right, there might be an easier way, so let me clarify. The purpose is to use the pulses as inflow and outflow for the same stock. Every time a new pulse goes in the stock, the previous pulse should come out of the stock. This is why I was ...

Hi, and thank you for your time and feedback! :D Knowing that there is a high chance that this can eventually never be possible is already very useful as it saves me time and effort from trying to make it happen! May I kindly ask for some clarity though with respect to your suggestion..? I assume th...

Hi! Attached you can find a model that creates pulses of random height and frequency. What I am trying to do, is to create a delay of these pulses, so that each pulse moves to the position of the next pulse, as shown in the attached figure. However, in the current model, this is only possible when t...

Thank you both for your answers once again! This clarified a lot! After using the PULSE TRAIN / TIME STEP approach for integration, the outcome was the behavior of the first screenshot. What happens essentially is that for every new pulse, the value of the previous pulse is retained and integrated w...

Hi, and thank you both for your answers! Much appreciated! I wanted to mention also in my first post that the INTEG function / level is something that I already tried, but the steps do not eventually reach the pulse peaks, as shown in the attached figure. It seems that the pulse duration is so small...

Hi!

Attached is a simple model with a ramp and a pulse train function, producing the behavior shown in the figure. I was wondering how it could be possible to produce a step pattern, following the peaks of the pulse train behavior, like the one drawn in the figure.

Thank you in advance!

Hello! The model below has a variable with two step inputs a and b, with b starting later than a, and another variable with their smoothing equivalents. Based on the fraction b/a of the step inputs when b starts, I am trying to make the starting point of smoothing b to be relative to the value of sm...

Attached a screenshot o the message by the way.

Hi,

Thanks for the reply. I am on a Mac, running dss double precision x64.

What email address should I use?

Hi, I am having an issue after the latest update. When I hover the mouse over the variables, I cannot see their description and units anymore. Also, not related to the latest update, is there any kind of file naming restriction? I have a model, say namecld.mdl. If I rename it to e.g. name0.mdl or na...

Hi,

Yes, that seems to work! Thank you!

Hi, This is the content of the .vensimdp file: [vensim] Units1=$,Dollar,Dollars,$s Units2=Day,Days Units3=Hour,Hours Units4=Month,Months Units5=Person,People,Persons Units6=Unit,Units Units7=Week,Weeks Units8=Year,Years ModelsOld0=/Users/aalto/Desktop/system dynamics/vensim online course/ex 7 epidem...

I don't think it is about a specific model, since I tested that on several models that units are not OK. Vensim crashes for all of them. Even for a model for which units were OK and Vensim displayed the relevant message on units check, when I changed the units of a variable to make the check wrong o...

Hi,

Mac Vensim 8.0.7, when I am trying a units check, if this is not OK, Vensim crashes. If units check is OK, the relevant message is showing.

I believe that should be a priority then.

As another member mentions above, Vensim is used heavily for teaching / educational purposes, in our case too, and this bug is not facilitating our effort.

Hello all,

Any update for that? I am using Vensim DSS 8.0.2 on a Mac and also facing the same problem.

Thanks.

Thanks for clarifying!

Hi! Thanks for replying! So, as far as I understand, levels can be used even if we are not accumulating tangible items, right? In order to model, for example, various behavioral aspects.

Hello! I am receiving a simultaneous equation error due to the fact that part of my model is about modelling behavior and the loops do not involve any stocks. This can be solved either by turning one of the variables to Level or with the Simultaneous function. The thing is, which one should I choose...

Hi!

We want to include our sensitivity graph in a scientific publication, however the quality of the image is not that good. Legends are small, lines are not that bold, plus that we cannot export to .eps. Any ideas? We are on Macs.

Thanks!

Yes, you are right about adding units.

Please run the model as it is, with a timestep of 0.5. Does the value of 103150000 that shows up for both "iPhone Installed Base" and "Android Installed Base" at year 2010 make sense to you?

From what I understand it should be 86750000.

Let me just double-check this with you, to see if there is something I misunderstand here. Let's just run the model with a 0.5 timestep. As far as I understand, this implies that the smartphone demand of 2009 for example, which is 173500000, will be evenly accumulated from the two installed bases in...

A 0.25 timestep would be suitable.

The four stocks, two installed bases and two app stocks, are not accumulating correctly at this timestep. And neither they do with a 0.5 timestep for example. They do accumulate correctly nevertheless with a timestep of 1.

Hello! Please find attached the model I am working on. What is not making sense, as I have mentioned, is that when timestep is set to 1, the installed bases (and the apps stocks) are accumulating fine, whereas when it is set to 0.25 or 0.5 they are not. Please feel free to ask in case anything is no...