Ventana software support forum

Hi colleagues, I'm conducting a sensitivity analysis for a dynamic model with probabilistic variables as part of an academic research project and need to determine the necessary number of simulations. By default, Vensim sets 200 simulations, and I used this value in my analysis. However, my reviewer...

Is there a way to edit the names of variables pasted from a list, a text file, or a similar method?

Hi everyone, I’m working on a Vensim model where I’ve repeated the same structure (containing 25 variables) seven times. Each structure has identical architecture, but the variables have distinct names for each repetition. When I copy-pasted the structure, Vensim automatically renamed the variables ...

Thank you, but I’m looking for an academic reference to justify the choice of a specific software.

Hi everyone, I’m looking for a paper or academic article that compares the capabilities and features of different system dynamics modeling software (e.g., Vensim, Stella, AnyLogic, Powersim, etc.). I’m particularly interested in analyses covering aspects such as ease of use, simulation capacity, gra...

thank you very much @aliakhavan89.

Hi, Could you please help me understand and interpret what each of the "Confidence Bounds" (50, 75, 90, 95, and 100%) represents in this generic graph, which is the result of performing sensitivity analysis by changing the value of a constant in the model "n" times using a random...

Please, can you explain me why this implementation did not work? (model attached)

Sure Administrator In my model, I've incorporated random variables using the RANDOM UNIFORM distribution to introduce randomness into certain behaviors. Following the advice of @tomfid, I've also created an auxiliary random variable to serve as the seed for the RANDOM UNIFORM variables. This has res...

It is possible to apply the multiple simulations with Pro version? thanks

Thank you so much for your replies! I truly appreciate the guidance. I'll endeavor to put @tomfid's solution into practice. As a doctoral student without external funding, my resources are limited, and I regret to inform you that I'm unable to acquire the DSS version due to financial constraints. Yo...

Is it possible to perform multiple simulations of a model at once in VENSIM PLE+?

I mean, I have a model that includes several random variables of the RANDOM UNIFORM type. I'd like to know if it's possible to obtain multiple runs of the model to obtain different results.

Thank you very much

thank you!

Is it possible in Vensim to configure a chart where we include two variables of different scales to include a secondary axis - with a different scale - that allows for better interpretation?

If there is the possibility, how do I implement it?

Thank you very much.

Could you please explain to me how I could implement a queue?

Thank you very much, you're right. You've made me reflect. The effect I'm trying to capture with "people quitting" is that individuals leave the course at any time from the beginning of its delivery (either because they don't like the course or because they found a better opportunity). And...

Dear,

Could you help me correct this model?

In the simulation, I'm getting negative values in the "Training" level variable, and I need it to always have values greater than or equal to 0.

I've tried several fixes but haven't been able to balance it.

Thank you very much.

Thank you very much for the detailed response. I understand your argument and Forrester's regarding the loss of certain complexity when discretizing, and I am reflecting on its implications. I'm thinking about an example model that represents a production line of tables using level variables (consid...

What is the most suitable approach for VENSIM and for the essence of SD? Should we model discrete variables (such as the number of employees in a company) as continuous or discrete variables? When considering the amount of personnel in a company, we never have fractions of people as employees; we al...

Thank you very much for the detailed explanation and the model @LAUJJL. I understand the point.

LAUJJL wrote: ↑Mon Mar 18, 2024 10:12 am Hi

I would add: units with 'use strict testing' on, in the model settings.

Regards.

JJ

Thank you very much for your advices! Please could you explain to me about the "use strict testing"?

I want to make an academic inquiry regarding SD. Currently, I'm finalizing the research for my Ph.D., where I employ SD as a modeling tool for a complex system. Essentially, without delving into specific or thematic details, in my thesis, I develop, based on literature review and expert interviews, ...

I mean I can´t open two or more models in the same instance.

When I open the another necesary model file in the same instance, the model that I have yet opened is replaced by the new open model.
What can I do?

Copy and paste properties between variables to apply same format.

The posibility of change between stock or auxiliar type variable without delete the original variable and re-writing it considering the new type.