Swarm is a platform for agent-based models ABMs that includes:
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A conceptual framework for designing, describing, and conducting experiments on ABMs;
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Software implementing that framework and providing many handy tools; and
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A community of users and developers that share ideas, software, and experience.
It mostly written in Objective-C but give ability to develop model in Java. In this article i give first introduction in Java Swarm and show how to run one of examples — Heatbugs.
Heatbugs — is one of our canonical Swarm demonstrations, an example of how simple agents acting only on local information can produce complex global behavior.
All commands in this article given for Debian GNU/Linux distribution (and must work similar on most other moder Linux distributions). Good article about building and running Swarm on Debian written by Jakson Aquino (but their article don’t contain information about Java Swarm).
Java installation
Currently i don’t have information about supporting GNU Java by Swarm, therefore i use Sun Java SE 1.6.0_03 as java virtual machine. To install Sun Java on Debian you have two options:
Build Swarm with Java support
Install the software necessary to download and compile swarm:
sudo apt-get install gobjc gperf libxpm-dev libpng12-dev automake1.9
emacs21-nox libhdf5-serial-dev blt-dev cvs autoconf libtool make
xfonts-75dpi xfonts-100dpi
Swarm needs automake1.9. Thus, run update-alternatives and select automake1.9 if it was not the default yet (For Debian Etch — automake 1.9 is already default version):
sudo update-alternatives —config automake
Now, you can download the swarm source code. There are two options:
Then, you can compile swarm with java support:
Swarm is already installed. You should now put this line at the end of your ~/.bashrc, because, by default, the Makefiles that come with swarm applications are configured to look for swarm at /usr, but since we installed it at /usr/local, we need to inform the Makefiles about this:
export SWARMHOME=/usr/local
In addition to putting the above line in your ~/.bashrc, copy and paste it in your terminal too. When you logoff and login again the .bashrc will be re-read and the SWARMHOME environment variable automatically will be active.
Build and run Heatbugs
You can download Heatbugs from Swarm ftp:
> wget http://ftp.swarm.org/pub/swarm/apps/java/sdg/jheatbugs-2.1.tar.gz
> tar -xvzf jheatbugs-2.1.tar.gz
> cd jheatbugs-2.1/
> make
If build failed with error like:
> HeatbugModelSwarm.java:297: cannot find symbol
> symbol : constructor FArgumentsImpl(HeatbugModelSwarm,swarm.Selector,boolean)
> location: class swarm.defobj.FArgumentsImpl
> new FCallImpl (this, proto, sel, new FArgumentsImpl (this, sel, true)));
> ^
> 1 error
Then you must download and apply my patch for jheatbugs:
> wget http://nixdev.net/projects/swarm/patches/jheatbug-2.1-FArgumentsImpl-parameters.diff
> patch -p1 -l < jheatbug-2.1-FArgumentsImpl-parameters.diff
After this you can repeate you build. If all finished OK — you can finally run this demo:
> javaswarm StartHeatbugs
Please note that javaswarm is a script written on top of java, which set proper environment settings and run swarm java application. Now you can play with Heatbug and see it evolution.
References
To be continued
