Vensim is a

simulation software Simulation software is based on the process of modeling a real phenomenon with a set of mathematical formulas. It is, essentially, a program that allows the user to observe an operation through simulation without actually performing that operation. ...

developed by Ventana Systems. It primarily supports

continuous simulation Continuous Simulation refers to simulation approaches where a system is modeled with the help of variables that change continuously according to a set of differential equations. History It is notable as one of the first uses ever put to computers ...

(

system dynamics System dynamics (SD) is an approach to understanding the nonlinear behaviour of complex systems over time using stocks, flows, internal feedback loops, table functions and time delays. Overview System dynamics is a methodology and mathematical ...

), with some discrete event and

agent-based model An agent-based model (ABM) is a computational model for simulating the actions and interactions of autonomous agents (both individual or collective entities such as organizations or groups) in order to understand the behavior of a system and wha ...

ling capabilities. It is available commercially and as a free "Personal Learning Edition".

Modeling environment

Vensim provides a graphical modeling interface with

stock and flow Economics, business, accounting, and related fields often distinguish between quantities that are stocks and those that are flows. These differ in their units of measurement. A ''stock'' is measured at one specific time, and represents a quantity e ...

and

causal loop diagram A causal loop diagram (CLD) is a causal diagram that aids in visualizing how different variables in a system are causally interrelated. The diagram consists of a set of words and arrows. Causal loop diagrams are accompanied by a narrative which de ...

s, on top of a text-based system of equations in a

declarative programming In computer science, declarative programming is a programming paradigm—a style of building the structure and elements of computer programs—that expresses the logic of a computation without describing its control flow. Many languages that ap ...

language. It includes a patented method for interactive tracing of behavior through causal links in model structure, as well as a language extension for automating quality control experiments on models called Reality Check. The modeling language supports arrays (subscripts) and permits mapping among dimensions and aggregation. Built-in allocation functions satisfy constraints that are sometimes not met by conventional approaches like

logit In statistics, the logit ( ) function is the quantile function associated with the standard logistic distribution. It has many uses in data analysis and machine learning, especially in data transformations. Mathematically, the logit is the ...

. It supports discrete delays, queues and a variety of stochastic processes. There are multiple paths for cross sectional and time-series data import and export, including text files, spreadsheets and ODBC. Models may be calibrated against data using optimization,

Kalman Filter For statistics and control theory, Kalman filtering, also known as linear quadratic estimation (LQE), is an algorithm that uses a series of measurements observed over time, including statistical noise and other inaccuracies, and produces estimat ...

ing or

Markov chain Monte Carlo In statistics, Markov chain Monte Carlo (MCMC) methods comprise a class of algorithms for sampling from a probability distribution. By constructing a Markov chain that has the desired distribution as its equilibrium distribution, one can obtain ...

methods. Sensitivity analysis options provide a variety of ways to test and sample models, including Monte Carlo simulation with Latin Hypercube sampling. Vensim model files can be packaged and published in a customizable read-only format that can be executed by a freely available Model Reader. This allows sharing of interactive models with users who do not own the program and/or who the model author does not wish to have access to the model's code base.

Applications

Vensim is general-purpose software, used in a wide variety of problem domains. Common or high-profile applications include: * Transportation and Energy * Business Strategy * Health * Security and Terrorism * Project Management * Marketing Science in Pharmaceuticals and Consumer Products *

Logistics Logistics is generally the detailed organization and implementation of a complex operation. In a general business sense, logistics manages the flow of goods between the point of origin and the point of consumption to meet the requirements of ...

* Environment

References

External links

Official Vensim web site

Official Ventana Systems, Inc. web site

SDM-doc documentation tool
ref>{{cite journal, last=Martinez-Moyano, first=I. J., year=2012, title=Documentation for model transparency, journal=System Dynamics Review, volume=28, issue = 2, pages=199–208, doi=10.1002/sdr.1471
Forio.com - host for online Vensim models
Environmental science software Mathematical software Numerical software Probabilistic software Risk management software Science software for macOS Science software for Windows Scientific simulation software Simulation programming languages Simulation software

Modeling environment

Applications

See also

References

External links