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5. Alife & Complex Systems

Alife takes yet another approach to exploring the mysteries of intelligence. It has many aspects similar to EC and Connectionism, but takes these ideas and gives them a meta-level twist. Alife emphasizes the development of intelligence through emergent behavior of complex adaptive systems. Alife stresses the social or group based aspects of intelligence. It seeks to understand life and survival. By studying the behaviors of groups of 'beings' Alife seeks to discover the way intelligence or higher order activity emerges from seemingly simple individuals. Cellular Automata and Conway's Game of Life are probably the most commonly known applications of this field. Complex Systems (abbreviated CS) are very similar to alife in the way the are approached, just more general in definition (ie. alife is a type of complex system). Usually complex system software takes the form of a simulator.

5.1 Alife & CS class/code libraries

These are libraries of code or classes for use in programming within the artificial life field. They are not meant as stand alone applications, but rather as tools for building your own applications.

Biome

Biome is a C++ library aimed at individual-based/agent-based simulations. It is somewhat similar to Swarm, EcoSim or Simex but tries to be more efficient and less monolithic without compromising object- oriented design. Currently there is an event based scheduling system, a C++ified Mersenne-Twister RNG, several general analysis classes, some Qt-based GUI classes, a very basic persistence/database framework (used also for parameter storage) and many other small useful things.

CASE

CASE (Cellular Automaton Simulation Environment) is a C++ toolkit for visualizing discrete models in two dimensions: so-called cellular automata. The aim of this project is to create an integrated framework for creating generalized cellular automata using the best, standardized technology of the day.

EcoSim

In EcoSim an ecosystem is described by all static and dynamic properties of the individuals involved in the system as well as time varying properties of the environment. Individuals change their state over time or due to internal and external events. The environment is also defined via dynamic objects which can change. Supports on the fly analysis and animation of generated data. It is a C++ class library designed to support individual-oriented modelling and simulation of ecological systems.

Integrating Modelling Toolkit

The Integrating Modelling Toolkit (IMT) is a generic, comprehensive, and extensible set of abstractions allowing definition and use of interoperable model components. Modellers create an IMT "world" made of IMT "agents" that will perform each a particular phase of a modelling task. The core set of IMT agents can describe generic, modular, distributed model components, either native to the IMT or integrating existing simulation toolkits, specialized for tasks that range from simple calculation of functions in an interpreted language to spatially explicit simulation, model optimization, GIS analysis, visualization and advanced statistical analysis. IMT agents are designed to easily "glue" together in higher-level simulations integrating different modelling paradigms and toolkits. The IMT can be easily extended by users and developers through a convenient plug-in mechanism

MAML

The current version of MAML is basically an extension to Objective-C (using the Swarm libraries). It consists of a couple of 'macro-keywords' that define the general structure of a simulation. The remaining must be filled with pure swarm-code. A MAML-to-Swarm (named xmc) compiler is also being developed which compiles the source code into a swarm application.

Simex

The SIMEX package contains a number of C++ classes that make it easier to build discrete-event, micropopulation models. (There is also some support for differential equation models.) It comes with a tuturial, quite a few examples and fairly decent documentation.

Swarm

The swarm Alife simulation kit. Swarm is a simulation environment which facilitates development and experimentation with simulations involving a large number of agents behaving and interacting within a dynamic environment. It consists of a collection of classes and libraries written in Objective-C and allows great flexibility in creating simulations and analyzing their results. It comes with three demos and good documentation.

5.2 Alife & CS software kits, applications, etc.

These are various applications, software kits, etc. meant for research in the field of artificial life. Their ease of use will vary, as they were designed to meet some particular research interest more than as an easy to use commercial package.

Achilles

Achilles is an evolution simulation based on Larry Yaeger's PolyWorld. It uses Hebbian neural networks, and an extremely simplified physical model that allows virtual organisms to interact freely in a simulated environment.

Avida

The computer program avida is an auto-adaptive genetic system designed primarily for use as a platform in Artificial Life research. The avida system is based on concepts similar to those employed by the tierra program, that is to say it is a population of self-reproducing strings with a Turing-complete genetic basis subjected to Poisson-random mutations. The population adapts to the combination of an intrinsic fitness landscape (self-reproduction) and an externally imposed (extrinsic) fitness function provided by the researcher. By studying this system, one can examine evolutionary adaptation, general traits of living systems (such as self-organization), and other issues pertaining to theoretical or evolutionary biology and dynamic systems.

BugsX

Display and evolve biomorphs. It is a program which draws the biomorphs based on parametric plots of Fourier sine and cosine series and let's you play with them using the genetic algorithm.

The Cellular Automata Simulation System

The system consists of a compiler for the Cellang cellular automata programming language, along with the corresponding documentation, viewer, and various tools. Cellang has been undergoing refinement for the last several years (1991-1995), with corresponding upgrades to the compiler. Postscript versions of the tutorial and language reference manual are available for those wanting more detailed information. The most important distinguishing features of Cellang, include support for:

  • any number of dimensions;
  • compile time specification of each dimensions size; cell neighborhoods of any size (though bounded at compile time) and shape;
  • positional and time dependent neighborhoods;
  • associating multiple values (fields), including arrays, with each cell;
  • associating a potentially unbounded number of mobile agents [ Agents are mobile entities based on a mechanism of the same name in the Creatures system, developed by Ian Stephenson (ian@ohm.york.ac.uk).] with each cell; and
  • local interactions only, since it is impossible to construct automata that contain any global control or references to global variables.

Creatures Docking Station

This is a free version of the Creatures3 ALife game. It has fewer species and a small 'space-station' world, but can connect to other worlds over the internet and (if you have the windows version of the game) can connect to your C3 world. The game itself revolves around breeding and training the alife creatures, 'Norns'. Its strikes a pretty nice balance between fun and science, or so I'm told.

dblife & dblifelib

dblife: Sources for a fancy Game of Life program for X11 (and curses). It is not meant to be incredibly fast (use xlife for that:-). But it IS meant to allow the easy editing and viewing of Life objects and has some powerful features. The related dblifelib package is a library of Life objects to use with the program.

dblifelib: This is a library of interesting Life objects, including oscillators, spaceships, puffers, and other weird things. The related dblife package contains a Life program which can read the objects in the Library.

Drone

Drone is a tool for automatically running batch jobs of a simulation program. It allows sweeps over arbitrary sets of parameters, as well as multiple runs for each parameter set, with a separate random seed for each run. The runs may be executed either on a single computer or over the Internet on a set of remote hosts. Drone is written in Expect (an extension to the Tcl scripting language) and runs under Unix. It was originally designed for use with the Swarm agent-based simulation framework, but Drone can be used with any simulation program that reads parameters from the command line or from an input file.

EcoLab

EcoLab is a system that implements an abstract ecology model. It is written as a set of Tcl/Tk commands so that the model parameters can easily be changed on the fly by means of editing a script. The model itself is written in C++.

Game Of Life (GOL)

GOL is a simulator for conway's game of life (a simple cellular automata), and other simple rule sets. The emphasis here is on speed and scale, in other words you can setup large and fast simulations.

gant

This project is an ANSI C++ implementation of the Generalized Langton Ant, which lives on a torus.

gLife

This program is similiar to "Conway's Game of Life" but yet it is very different. It takes "Conway's Game of Life" and applies it to a society (human society). This means there is a very different (and much larger) ruleset than in the original game. Things need to be taken into account such as the terrain, age, sex, culture, movement, etc

Langton's Ant

Langton's Ant is an example of a finite-state cellular automata. The ant (or ants) start out on a grid. Each cell is either black or white. If the ant is on a black square, it turns right 90 and moves forward one unit. If the ant is on a white square, it turns left 90 and moves forward one unit. And when the ant leaves a square, it inverts the color. The neat thing about Langton's Ant is that no matter what pattern field you start it out on, it eventually builds a "road," which is a series of 117 steps that repeat indefinitely, each time leaving the ant displaced one pixel vertically and horizontally.

LEE

LEE (Latent Energy Environments) is both an Alife model and a software tool to be used for simulations within the framework of that model. We hope that LEE will help understand a broad range of issues in theoretical, behavioral, and evolutionary biology. The LEE tool described here consists of approximately 7,000 lines of C code and runs in both Unix and Macintosh platforms.

MATREM

Matrem is a computer program that simulates life. It belongs to the emerging science of "artificial life", which studies evolution and complex systems in general by simulation. Matrem is also a game, where players compete to create the fittest lifeform. Their efforts are the driving force behind the program.

Net-Life & ZooLife

*(netlife-2.0.tar.gz contains both Net-Life and ZooLife)

Net-Life is a simulation of artificial-life, with neural "brains" generated via slightly random techniques. Net-Life uses artificial neural nets and evolutionary algorithms to breed artificial organisms that are similar to single cell organisms. Net-life uses asexual reproduction of its fittest individuals with a chance of mutation after each round to eventually evolve successful life-forms.

ZooLife is a simulation of artificial-life. ZooLife uses probabilistic methods and evolutionary algorithms to breed artificial organisms that are similar to plant/animal zoo organisms. ZooLife uses asexual reproduction with a chance of mutation.

POSES++

The POSES++ software tool supports the development and simulation of models. Regarding the simulation technique models are suitable reproductions of real or planned systems for their simulative investigation.

In all industrial sectors or branches POSES++ can model and simulate any arbitrary system which is based on a discrete and discontinuous behaviour. Also continuous systems can mostly be handled like discrete systems e.g., by quantity discretion and batch processing.

Primordial Soup

Primordial Soup is an artificial life program. Organisms in the form of computer software loops live in a shared memory space (the "soup") and self-reproduce. The organisms mutate and evolve, behaving in accordance with the principles of Darwinian evolution.

The program may be started with one or more organisms seeding the soup. Alternatively, the system may be started "sterile", with no organisms present. Spontaneous generation of self-reproducing organisms has been observed after runs as short as 15 minutes.

Tierra

Tierra's written in the C programming language. This source code creates a virtual computer and its operating system, whose architecture has been designed in such a way that the executable machine codes are evolvable. This means that the machine code can be mutated (by flipping bits at random) or recombined (by swapping segments of code between algorithms), and the resulting code remains functional enough of the time for natural (or presumably artificial) selection to be able to improve the code over time.

TIN

This program simulates primitive life-forms, equipped with some basic instincts and abilities, in a 2D environment consisting of cells. By mutation new generations can prove their success, and thus passing on "good family values".

The brain of a TIN can be seen as a collection of processes, each representing drives or impulses to behave a certain way, depending on the state/perception of the environment ( e.g. presence of food, walls, neighbors, scent traces) These behavior process currently are : eating, moving, mating, relaxing, tracing others, gathering food and killing. The process with the highest impulse value takes control, or in other words: the tin will act according to its most urgent need.

XLIFE

This program will evolve patterns for John Horton Conway's game of Life. It will also handle general cellular automata with the orthogonal neighborhood and up to 8 states (it's possible to recompile for more states, but very expensive in memory). Transition rules and sample patterns are provided for the 8-state automaton of E. F. Codd, the Wireworld automaton, and a whole class of `Prisoner's Dilemma' games.

Xtoys

xtoys contains a set of cellular automata simulators for X windows. Programs included are:

  • xising --- a two dimensional Ising model simulator,
  • xpotts --- the two dimensional Potts model,
  • xautomalab --- a totalistic cellular automaton simulator,
  • xsand --- for the Bak, Tang, Wiesenfeld sandpile model,
  • xwaves --- demonstrates three different wave equations,
  • schrodinger --- play with the Scrodinger equation in an adjustable potential.


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