Swarm MPM Simulation Tools -- Breve and Swarm Anguo Dong Computer - - PDF document

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MPM Simulation Tools -- Breve and Swarm

Anguo Dong Computer Science Department University of Calgary donga@cpsc.ucalgary.ca

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Swarm

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What is Breve (I)

• A free simulation environment designed

for multi-agent simulation.

• Allows users to define the behaviors of

autonomous agents in a continuous 3D world, then observe how they interact.

• Includes support for a rich visualization

engine, realistic physical simulation and an easy-to-use scripting language.

• Used as a tool to explore any type of

simulated world.

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What is Breve (II)

• Used for a wide variety of simulation

applications: simulated virtual creatures, artificial ecosystems, simulations of molecular biology, visualization and much more.

• Facilitates the construction of complex

agent-based simulations by automatically handling agent communication, representation in 3D space, graphical rendering, physical simulation and a number of other features which are useful to agent-based simulations.

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The Origin of Breve

• Initiated by Jon Klein as a thesis

project at Hampshire College and was developed further into a Master's thesis at Chalmers University

• Platform for a project building

large scale simulations of evolutionary dynamics

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Multi-Agent Simulation

• The term agent refers to any object in a

simulated world, but in particular, an object with autonomous behaviors which interacts with its environment and other agents.

• A multi-agent simulation is a simulation in

which multiple agents exist and interact in the simulated world.

• An example of a multi-agent simulation is an

ecosystem simulation: a large number of autonomous agents (animals) interacting with each other (eating and breeding) and the environment.

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Physical Simulation

• breve is capable of realistic physical

simulation.

• Agents in the simulated world can be

configured to behave just as real

• bjects do, according to the laws of

physics.

• Used for realistic simulation of robots,

vehicles and animals.

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3D Spatial Simulation

• breve simulates 3D physical space and

that simulated agents occupy and interact in this physical space.

• Used for realistic simulations involving

space, such as physical simulations.

• Contrast to simulation environments

which model space in 2D or which treat "space" only as an abstract concept.

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Install and Run breve on Mac OS X

• Simply drag the application

(breve.app) into your /Applications folder (or to any other folder where you wish to put the program).

• To get started with breve, simply

double-click the breve application.

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Installation on Unix(Linux) and Windows

• Install OpenGL and GLUT libraries

– Put the glut32.dll to your windows/system/ directory

• Setting Up Your Environment - BREVE_CLASS_PATH

– # tcsh users (Linux & OSX): setenv BREVE_CLASS_PATH /<path to breve>/lib/classes – # bash users (Linux & OSX): export BREVE_CLASS_PATH=/<path to breve>/lib/classes – # Windows console users: SET BREVE_CLASS_PATH=C:\<path to breve>\LIB\CLASSES – <path to breve> -- location of the breve distribution folder that you downloaded

• For this machine

– C:\WINDOWS\system\glut32.dll – In AUTOEXEC.BAT SET BREVE_CLASS_PATH=D:\Anguo\Courses\CPSC607\MBM- tool\breve\breve_2.1\lib\classes

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Running on Unix(Linux) and Windows

• Running the Demo Simulations

– # Linux & OSX % ./bin/breve ./demos/Swarm/ArrowSwarm.tz – # Windows

> bin\breve.exe demos\Swarm\ArrowSwarm.tz

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Controls of simulation

• Space bar: pause/resume the simulation
• F1: run simulation forward one iteration step
• Left mouse: rotate simulation and select objects
• Right mouse click: display the simulation menu
• Right mouse click (when an object is selected):

display a contextual menu for the object

• Control (or F2) + left mouse: zoom in and out of

the simulation

• Alt (or F3) + left mouse: move the camera
• Shift (or F4) + left mouse: select and drag objects

in the simulation

• Escape: to quit the simulation, or access the breve

command prompt

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“steve" Language Reference

• Simulations in breve are written using a

language called "steve"

• steve aims to allow rapid construction of

advanced simulations

• "steve" is an object-oriented language
• Objects can be either real, meaning they

have a presence in the simulated world;

• r abstract

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Building Classes

• Defining Classes

– superClass:subclass {} – # first without the alias... Mobile : myMobile { } – # now with the alias... Mobile : myMobile (aka myMobiles) { }

• Defining Instance Variables

– variable_name (variable_type) – Mobile : myMobile { + variables: myInt, myOtherInt (int). myObject (object). myFloat (float). }

• Defining Methods

– + to methodName:

• Creating and Destroying Instances

– new object_type. number new object_type. – free instance.

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Defining Basic Agents

• To create a simple agent in breve, you'll

need to subclass one of the basic agent classes, all subclasses of Real

• Stationary, an immobile object in the

simulated world.

• Mobile, an object which moves around the

simulated world.

• Link, a physically simulated mobile object.

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A Simple Mobile Agent

Mobile : Bird {

+ variables: myShape (object). + to init: myShape = (new Cube init-with size (1, 1, 1)). self set-shape to myShape. + to iterate: }

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Change Appearance of Agents

• Shape

– init-with-cube – init-with-polygon-cone – init-with-polygon-disk – init-with-sphere

• Color

– self set-color to (0.0, 1.0, 0.0).

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Moving Agents Around the 3D World

• # move the agent to the location (10,

0, 0) in 3D space...

– self move to (10, 0, 0).

• # set the agent's velocity to (0, 0, 10)

– self set-velocity to (0, 0, 10).

• # set the agent's acceleration to (0, -

9.8, 0)

– self set-acceleration to (0, -9.8, 0).

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Scheduling Events for a Specific Time

• # call a method after the simulation

clock hits 100.0...

– self schedule method-call "sing-and- dance" at-time 100.0.

• # call a method 100.0 seconds from

now...

– self schedule method-call "sing-and- dance" at-time ((controller get-time) + 100.0).

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Hello world

@include "Control.tz" Controller HelloWorld. Control : HelloWorld { + to iterate: print "Hello, world!". }

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Randomwalk

@use Control. @use Mobile. Controller myControl. Control : myControl { + variables: walkerShape (object). + to init: print "Setting up the simulation.". self point-camera at (0, 0, 0) from (0, 60, 0). walkerShape = (new Sphere init-with radius 1). 200 new RandomWalker. + to get-walker-shape: return walkerShape. } Mobile : RandomWalker { + to init: self set-shape to (controller get-walker-shape). self set-color to random[(1.0, 1.0, 1.0)]. + to iterate: self set-velocity to random[(60, 60, 60)] - (30, 30, 30). }

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Controller Object

• Foundation of a breve simulation - first

step in writing a breve

• "boss" for the simulation--create and set

up the rest of the simulation.

• The only object which is automatically

instantiated when the simulation begins

• Like the main function in C or C++
• Must be a subclass of the class Control or
• ne of its subclasses.

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Interactions Between Agents

• Speak to controller object
• Agents collide

– handle-collisions method in Real.tz

• Finding Neighboring Objects

1. Set each agent's "neighborhood size". 2. Ask the engine to update the neighbors at each iteration. 3. Retrieve each agents list of neighbors at each timestep.

• Finding the Closest Object

– possible that the closest object is not within an object's neighborhood

• Finding All Objects of a Given Type

– using the "all" expression – myMobile = all Mobiles

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Origin of Swarm

• Started in 1994 by Chris Langton,

at Santa Fe Institute (SFI)in New Mexico

• The aim was to develop both a

vocabulary and a set of standard computer tools for the development

• f multi-agent simulation models

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Introduction To Swarm

• Swarm Code is Object-Oriented
• Swarm Programs are Hierarchical
• Swarm Provides Many Handy

Tools

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Agent-based Modeling

http://lark.cc.ku.edu/~pauljohn/Swarm/Beta/SwarmUserGuide /swarm.user.user1.02.chapter.html

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Object in Swarm

• Variables.

– "state" of the agent--its age, wealth, its ability, and so forth. – Of any type that is allowed in C, such as integer (int), floating-point number (float), an array, a pointer, and so forth. – Of type id -- be instances of classes

• Methods.

– Methods determine what the object can do – Receive information from the "outside world" – Send messages to the outside – Process information

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Merging Schedule

http://lark.cc.ku.edu/~pauljohn/Swarm/Beta/SwarmUser Guide/swarm.user.user1.04-schedule.sect1.html This multi-level integration of swarm schedules means that the model can indeed be thought of as a nested hierarchy of models.

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A Swarm as a Virtual Computer

http://lark.cc.ku.edu/~pauljohn/Swarm/Beta/SwarmU serGuide/swarm.user.user1.04-schedule.sect1.html

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Element of Swarm GUI

http://lark.cc.ku.edu/~pauljohn/Swarm/Beta/SwarmUser Guide/swarm.user.user1.05.chapter.html Line graph (time series) Histogram Raster

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Install and Run Swarm

• GNU/Linux binaries
• MacOS X 10.3 binaries
• Swarm Windows binaries

– Distributed as an executable file that installed Cygwin and Swarm on your computer – Swarm works within the Unix-like environment provided by Cygwin – With latest Version 2.2, including Swarm as a package within a special Cygwin distribution.

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Uninstall Swarm and Cygwin

• Cygwin does not come with an

uninstaller

• Must be manually uninstalled.

– Delete all its files manually – Manually remove any entries related to Cygwin in the Windows registry (via the command-line program "regedit")

• Big size – 115mb

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Resources

• http://www.spiderland.org
• http://www.santafe.edu/
• http://www.swarm.org/index.html
• http://lark.cc.ku.edu/~pauljohn/Swarm

/Beta/SwarmUserGuide/userbook.ht ml

• Braitenberg Vehicles tutorial -- as a

quick way to get started with a fun simulation in breve