mas

JavaScript Modeling and Simulation

This library implements basic components required for modeling and simulation in JavaScript. It currently supports a portion of the System Dynamics (SD) formalism.

This package adopts the RequireJS interface for dual use in Node or a browser.

SD Components and Functions

* Stock (mas.sd.Stock)
* Flow (mas.sd.Flow)
* Parameter (mas.sd.Parameter, a Flow with constant value)
* Delay1 (mas.sd.Delay1, first-order exponential delay function)
* Smooth (mas.sd.Smooth, first-order exponential smoothing function)

Simulators and Integration Methods

* Simulator (mas.sim.Simulator, a basic simulator with event bindings)
* LoggingSimulator (mas.sim.LoggingSimulator, logs entity values at each time step)

Known limitations:
* The current time advancement as a decentralized tick/tock procedure only allows an explicit (forward) Euler integration method. More precise methods such as 4th order Runge-Kutta (RK4) would require either a centralized state update function or more numerous iterative data exchange periods.
* Results cannot be directly compared to outputs of some tools due to a difference in numerical precision. For example, most versions of Vensim only support single-precision floating-point numbers while JavaScript is double-precision.