This volume offers a detailed look at a new environment for systems modeling based on the open matrix language (OML), a relatively new language for numerical computation in the tradition of MATLAB, Octave, Scilab, and Julia. The environment includes Compose (an interactive development environment) and Activate (a graphical block modeling environment). The system supports extensive integration: Compose can include user-defined C/C++ functions and bridges to Python and Tcl/Tk, while Activate supports libraries in Modelica and Spice. OML itself is compatible with Octave.

In the crowded space of numerical computation languages, OML with Compose and Activate appears to be distinguished by its marketing model. MATLAB is a commercial product. Octave, Scilab, and Julia are open source, though paid consulting services are widely available. OML, Compose, and Activate are produced by Altair, a commercial company, which offers not only consulting services, but also commercial versions of the Compose and Activate environments and other related tools. The value proposition for users is a powerful free environment for initial exploration that enjoys the development and maintenance support of a commercial software company. Whether this support is technically more robust than the open-source model is debatable, but there is no question that for many commercial customers, open source appears threatening and somewhat anarchic, and the additional comfort of a commercial product, together with the low entry cost of free basic versions, is highly attractive.

The first five chapters introduce OML and the Compose development environment. The reader is led through the development execution of a range of different kinds of models, including ordinary differential equations (ODEs), boundary value problems, difference equations, and differential algebraic equations, and introduced to functions provided by OML, including root finding and optimization. After this introduction, several detailed examples are presented, including open-loop pendulum control and a delayed predator-prey model.

The last ten chapters describe the Activate system for composing modular systems in a block diagram and compiling and running them. Activate supports not only signal passing systems, but also Modelica models, and can pass information back and forth between Modelica and conventional block diagrams. It also supports hybrid models, which combine continuous-time and discrete-event models. The chapters walk readers through numerous examples that illustrate the capabilities of the system, including import from Simulink and co-simulation with the functional mock-up interface (FMI), MotionSolve, and HyperSpice (Altair’s version of the Spice system for circuit simulation).

The clarity and detail of this tutorial volume, together with the richness of OML and the sophistication of the Compose and Activate interfaces, offer a promising resource for introducing students to numerical simulation, whether in the classroom or in self-study.