Introduction to Java Swarm for ABM
Swarm is a platform for agent-based models ABMs that includes:
- A conceptual framework for designing, describing, and conducting experiments on ABMs;
- Software implementing that framework and providing many handy tools; and
- 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:
- Use Debian backports and install sun-java6-jdk
-
Download binary distribution from official Sun Java site and install it manually
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:
Paul Johnson’s web site:
wget http://pj.freefaculty.org/Swarm/swarm-2.2.3.tar.gz tar -xzf swarm-2.2.3.tar.gz cd swarm-2.2.3
The official cvs repository:
cvs -z3 -d:pserver:anonymous@cvs.savannah.nongnu.org:/sources/swarm co swarm cd swarm ./autogen.sh
Then, you can compile swarm with java support:
If you install Java from backport package:
./configure —with-jdkdir=/usr/lib/jvm/java-6-sun —with-gnu-ld —with-tclinclude=/usr/include/tcl8.4/ —with-tclscriptdir=/usr/lib/tcl8.4/ —with-tkscriptdir=/usr/lib/tk8.4/ —with-tcl=/usr/lib/tcl8.4/ —with-tk=/usr/lib/tk8.4 —with-tkinclude=/usr/include/tcl8.4
If you install Java from binary distribution archive — replace java_path on real Java installation path:
For swarm from cvs
./configure —with-jdkdir=java_path —with-gnu-ld —with-tclinclude=/usr/include/tcl8.4/ —with-tclscriptdir=/usr/lib/tcl8.4/ —with-tkscriptdir=/usr/lib/tk8.4/ —with-tcl=/usr/lib/tcl8.4/ —with-tk=/usr/lib/tk8.4
make
sudo make install
For swarm 2.2.3
./configure —with-jdkdir=java_path —with-gnu-ld —with-tclincludedir=/usr/include/tcl8.4/ —with-tclscriptdir=/usr/lib/tcl8.4/ —with-tkscriptdir=/usr/lib/tk8.4/ —with-tcldir=/usr/lib/tcl8.4/ —with-tk=/usr/lib/tk8.4
make sudo make install
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
- Additional information about swarm can be found on Swarm wiki and Swarm application examples.
- Information about build and run ObjectiveC version of Swarn available on Jakson Aquino swarm page.
To be continued
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