Abstract

People use \CC because it is both powerful and efficient. People use Tcl and Tk because they allow rapid prototyping, simple scripting and building of graphical interfaces with great ease.

My approach is that one should use each language for what it does best, and so I have built a series of libraries which link \CC and Tcl. The way in which I use these libraries for my research is as follows: \CC simulation objects are coded, then simulations are created via simple Tcl scripts (either manually or by the GUI which records actions automatically). These simulations can then run without sacrificing any of \CC's efficiency, yet they may still be adjusted, examined or changed on the fly using Tcl.

EvoX's a cool tool for the simulation of complex systems. It's an object based, \CC class system with various analysis tools included. EvoX has a tcl/tk interface, large parts of which use the `[incr tcl]' extension for object oriented capabilities. This provides a largely parallel class hierarchy embodying the interface-relevant parts of a given model world. EvoX is very simply extensible and specialisable both in terms of creating new \CC objects for a user's simulations and in terms of extending the interface if desired (although this is not normally necessary). Lastly EvoX uses a distributed programming paradigm so that simulations running locally or remotely may be examined, adjusted and analysed using a single interface.

Overview

EvoX stands for `Evolution in complex systems'. It is a simulation environment, designed for the investigation of emergent phenomena, but sufficiently general that it can be used for many purposes. For example I have used EvoX for studying the effects of a deforming topology on an evolving population, feedback interactions in a simple artificial economy of agents and comparative studies of optimisation algorithms on travelling salesman problems.

EvoX is based around a \CC class hierarchy implementing simulation and analysis objects, overlain with a Tcl/Tk object-oriented graphical user interface. As well as communicating with each other in the usual \CC fashion of public interfaces and member function calls, EvoX provides a secondary method in which objects explicitly declare observables and events they can provide and sockets which other events may call. This `EvoX-interface' (provided by, but only a part of the \CC interface) is manipulated by the EvoX environment.

EvoX currently requires the latest release of Tcl (as of May 1996). This is Tcl7.5. It includes cross-platform support (for Unix, MacOS and Windows), and supports dynamic loading of Tcl extensions, which is why older versions are not supported.