The term “simulation” is used in different ways by different people. Most existing simulation tools fall into one of three categories: 1) discrete simulators; 2) system dynamics programs; and 3) probabilistic spreadsheet programs. A brief overview of how GoldSim differs from these approaches is provided below:
Discrete Simulators
Discrete simulators generally rely on a transaction-flow approach to modeling systems. Models consist of entities (units of traffic), resources (elements that service entities), and control elements (elements that determine the states of the entities and resources). Discrete simulators are generally designed for simulating detailed processes such as call centers, factory operations, and shipping facilities.
- GoldSim is designed to build “top-down” models of complex systems that focus on “big picture” long-term, strategic issues (rather than “factory floor” tactical issues). As such, it is much better at simulating systems that have many diverse components (e.g., physical, social and financial) that must be coupled together in order to understand the behavior of the entire system (e.g., strategic business models and complex supply chains).
- GoldSim can simulate both discrete events (transactions) and continuous processes simultaneously. That is, it can superimpose discrete events onto a continuously varying system. This is a distinct advantage when a system includes bulk material flow (e.g., fuel, ore, electricity, water) or a very high rate of transactions that can be simulated more efficiently as a continuous process (e.g., retail sales).
- GoldSim is generally better at simulating complex systems whose behavior is difficult to predict and/or poorly understood such that they have a high degree of uncertainty.
System Dynamics
System dynamics software is based on the standard stock and flow approach developed by Professor Jay W. Forrester at MIT in the early 1960s. Models based on system dynamics are built using three types of elements (stocks, flows, and converters). System dynamics software packages are generally used for simulating general business and organizational systems and simple engineering and scientific systems.
Although GoldSim is similar to system dynamics programs in many ways (and can simulate any system that a system dynamics tool can), GoldSim moves beyond system dynamics software by offering the following combination features:
- GoldSim provides the ability to superimpose the occurrence and consequences of discrete events (e.g., financial transactions, accidents, labor strikes, lawsuits) onto continuous systems.
- GoldSim includes a much broader range of elements that make the model logic and structure more transparent.
- GoldSim has much more powerful features for allowing the user to quantify uncertain and stochastic systems.
- GoldSim’s hierarchical approach and other specialized features allow you to build and efficiently maintain highly complex models (consisting of thousands of objects) without losing the ability to explain the models to a non-technical audience.
- GoldSim is dimensionally aware and allows you to use any kind of units in your model. GoldSim checks for dimensional consistency and carries out the conversions for you automatically.
- GoldSim was designed to accommodate the addition of specialized extension modules (e.g., GoldSim CT for simulating the fate and transport of environmental constituents).
Probabilistic Spreadsheet Programs
Probabilistic spreadsheet programs are add-on programs for Microsoft Excel that allow users to define probabilistic distributions for input parameters. Any type of system that can be represented in a spreadsheet can be simulated using probabilistic spreadsheet programs. One advantage of these programs compared with all other classes of simulation software is that most users are already familiar with spreadsheet programs.
GoldSim differs from probabilistic spreadsheet software in the following manner:
- GoldSim is much better at simulating dynamic systems that evolve with time.
- GoldSim’s graphical user interface makes it much easier to understand, demonstrate, and document the model logic and structure.
- Although GoldSim’s object-oriented graphical interface is better for showing model logic, spreadsheets are better suited for rapidly assembling large amounts of data and calculations in a single view.
- GoldSim’s hierarchical approach allows simulation of highly complex systems without losing the ability to understand and explain the model. In other words, any spreadsheet model that involves multiple worksheets is probably easier to understand and explain using GoldSim.
- GoldSim is dimensionally aware and allows you to use any kind of units in your model. GoldSim checks for dimensional consistency and carries out the conversions for you automatically.
- GoldSim allows the user to build player files that can be viewed by anyone using GoldSim Player A program that allows you to "play" or "read" an existing GoldSim model without having to license the GoldSim software. The GoldSim Player is available as a free download from the GoldSim website., a free download.
- GoldSim is designed to accommodate the addition of specialized extension modules (e.g., GoldSim CT for simulating the fate and transport of environmental constituents).
Note that GoldSim supports seamless integration with existing spreadsheet models via a specialized element that allows the user to dynamically pass data to and from a spreadsheet during a simulation.