Supporting material for the paper:
Is your model susceptible to floating-point errors?

Luis R. Izquierdo and J. Gary Polhill

All the software in this web page is released under the GNU General Public Licence. Clicking any of the source download links will be taken as an assertion that you agree to abide by the terms of this licence.

| RAEAN (Reimplementation of Axelrod's "Evolutionary Approach to Norms")
| The Artificial Stock Market, or ASM
| FEARLUS
| BM
| CASD
| CharityWorld
| Implementation of every technique (Tolerance windows, Strings, Rational arithmetic, and Interval arithmetic)
| References

RAEAN (Reimplementation of Axelrod's "Evolutionary Approach to Norms")

RAEAN-1a

Reimplementation of Axelrod's "Evolutionary Approach to Norms" (1986), created in Java by José M. Galán and Luis R. Izquierdo (2005). For a detailed explanation of the model, an applet, a user guide, and the paper about their work, visit http://www.insisoc.org/metanorms/.

This file (RAEAN-1a.zip) includes a java stand-alone application, the java source code, the parameters used to create figures 4 and 5, and the parameters used to run the simulations that demonstrate the following statement:

RAEAN-1b

Modified version of the original RAEAN, where condition [1a] was replaced with condition [1b] (See paper).

This file (RAEAN-1b.zip) includes a java stand-alone application, the java source code, and the parameters used to create figure 5.

The Artificial Stock Market, or ASM

Artificial Stock Market: Original program, implemented by Paul E. Johnson (2002).

Modified versions used to investigate the impact of floating-point errors in the original implementation (Polhill and Izquierdo 2005; Polhill, Izquierdo and Gotts 2005).

FEARLUS

This file (FEARLUS-model0-7-1.tar.gz) contains FEARLUS-model0-7-1, the (free-from-floating-point-errors) version of FEARLUS (Polhill, Gotts, and Law 2001; Gotts, Polhill, and Law 2003) that we used to conduct the experiments explained in the paper. FEARLUS-model0-7-1 is known to work on a Sun machine running Solaris 2.8 with Swarm snapshot 2001-12-18. You can also download some parameter files for two demos, and the scripts that we used to run all the experiments that we conducted for the paper. A user guide for FEARLUS can be found at http://www.macaulay.ac.uk/fearlus/download.html.

If you would like to run FEARLUS-model0-7-1 on Cygwin, please install this other version (FEARLUS-model0-7-1ci.tar.gz), and use Swarm 2.1.1.

BM

This is a Mathematica file (BM.nb) with our reimplementation of the BM model used by Macy and Flache (2002), and Flache and Macy (2002). We used this Mathematica file to create figure 6.

CASD

You can find the Objective-C source code and a user guide for CASD at http://www.macaulay.ac.uk/fearlus/casd/, by Izquierdo, Gotts, and Polhill (2004).

CharityWorld

You can find the Objective-C source code for CharityWorld at http://www.macaulay.ac.uk/fearlus/floating-point/charity-world/. Polhill, Izquierdo and Gotts (2006) give an in-depth explanation of the model.

Implementation of every technique (Tolerance windows, Strings, Rational arithmetic, and Interval arithmetic)

This file (DoubleSimple-1.2.tar.gz) contains an implementation of every technique that we investigate in the paper, and some more. These techniques have been implemented as Objective-C classes and they are known to work on a Sun machine running Solaris 2.8. They can also be used on an Intel Pentium PC with Cygwin installed as long as you install CIieeefp first.

References

AXELROD R M (1986) An Evolutionary Approach to Norms. American Political Science Review, 80 (4). pp. 1095-1111.

FLACHE A and Macy M W (2002) Stochastic Collusion and the Power Law of Learning. Journal of Conflict Resolution, 46 (5). pp. 629-653.

GALÁN J M and Izquierdo L R (2005) Appearances Can Be Deceiving: Lessons Learned Reimplementing Axelrod's ‘Evolutionary Approach to Norms’. Journal of Artificial Societies and Social Simulation, 8 (3), http://jasss.soc.surrey.ac.uk/8/3/2.html

GOTTS N M, Polhill J G, and Law A N R (2003) Aspiration levels in a land use simulation. Cybernetics & Systems, 34 (8). pp. 663-683.

IZQUIERDO L R, Gotts N M, and Polhill J G (2004) Case-Based Reasoning, Social Dilemmas, and a New Equilibrium Concept. Journal of Artificial Societies and Social Simulation, 7 (3), http://jasss.soc.surrey.ac.uk/7/3/1.html

JOHNSON P E (2002) Agent-Based Modeling: What I Learned from the Artificial Stock Market. Social Science Computer Review, 20. pp. 174-186.

MACY M W and Flache A (2002) Learning Dynamics in Social Dilemmas. Proceedings of the National Academy of Sciences USA, 99, Suppl. 3. pp. 7229-7236.

POLHILL J G, Gotts N M, and Law A N R (2001) Imitative and nonimitative strategies in a land use simulation. Cybernetics & Systems, 32 (1-2). pp. 285-307.

POLHILL J G and Izquierdo L R (2005) Lessons learned from converting the artificial stock market to interval arithmetic. Journal of Artificial Societies and Social Simulation, 8 (2), http://jasss.soc.surrey.ac.uk/8/2/2.html

POLHILL J G, Izquierdo L R and Gotts N M (2005) The ghost in the model (and other effects of floating point arithmetic). Journal of Artificial Societies and Social Simulation, 8 (1), http://jasss.soc.surrey.ac.uk/8/1/5.html

POLHILL J G, Izquierdo L R and Gotts N M (2006) What every agent based modeller should know about floating point arithmetic. Environmental Modelling & Software, 21 (3), March 2006. pp. 283-309.