System Dynamics Calculator

                The Calculator

                        An Introduction to System Dynamics Models

                        Basic Calculator Architectures

                        Calculator User Interface

                        Conventional Calculator Functionality

                The SD Model in Depth

                The Model Builder

                The Model Simulator

                Appendix: The Modeling Process

                System Dynamics CalculatorR1.pdf


The System Dynamics Calculator has a user interface that runs on a variety of platforms including smart phones and PDAs, laptop computers and desktop computers.  The calculator operates on a model of a dynamic system with methods and techniques that are to be defined by a global standard body to insure compatibility with models that are created by other compliant model builders around the world.  The calculator presents a rich, visually appealing interactive environment for the user to explore the behavior of a dynamic system, project future system behavior and compute optimal solutions to complex real-life problems.  The System Dynamics Calculator includes a Model Builder process and a Model Simulator process. 

The System Dynamics Calculator immediately prompts the user to select and load a model to simulate.  The calculator presents at least one of several options to the user to begin a simulation:

  1. select a model from a library of locally installed models

  2. select a model from local media such as a memory card or a USB storage device

  3. select a model from remote libraries available over the Internet

  4. build a new model from scratch

  5. use a conventional calculator

Once a model is loaded, the calculator’s Model Simulator identifies and loads essential initial data for the model:

  1. user-input values for constants and for initial stock levels

  2. local datasets such as TAL files exported from personal finance software

  3. remote datasets from websites such as US Census Bureau or the New York Stock Exchange

Next, the Model Simulator prompts the user to specify other simulation criterion and options that are desired. The model’s simulation strategy allows for statistically shaped random number generation, multiple trials and a host of other tools to produce meaning information and solutions for the user.  Typical simulation options that the model supports including the following:

  1. beginning and ending simulation time and trial time increment

  2. speed of the simulation such as fastest, or one trial per second, for example

  3. goal value for a stock or flow level by adjusting other designated stocks or flows

  4. optimizer trial values for constants and other variables to be adjusted through a range

  5. number of simulations if something other than the default is desired

  6. confidence or statistical deviation specification such as 3-sigma for a goal value that is the result of one or more random number input values in the model

The results of the simulation can be presented to the user in customizable graphs and charts for any stock, flow or transformer value in the model

The user is able to query the Model Simulator to analyze the simulation results further to determine something of the significance from the results.  For example, the user is able to:

  1. calculate the min, max, mean and standard deviation for any result level

  2. calculate the correlation between any two stocks or flows

  3. graph velocity and acceleration of stocks and flows

  4. graph the sensitivity of stocks and flows relative to a specified stock or flow

  5. designate variables to be random values shaped to a specified probability distribution

  6. solve for a level = a target by adjusting a specified variable in a specified range for a solution

  7. solve for a level = a target and a second criterion such as a minimum or maximum for another level value by adjusting a set of variables in a specified range for a solution

System Dynamics Calculator  

An Introduction to System Dynamics Models →