Replication of Macroeconomics from the Bottom-up

Replication of the MacroABM Model

Richárd O. Legéndi, László GulyásEötvös Loránd University, AITIA International, Inc

[email protected], [email protected]

17th Annual Workshop on Economic Heterogeneous Interacting Agents WEHIA 2012, Paris, June 21-23, 2012

Supported by the Hungarian Government (KMOP-1.1.2-08/1-2008-0002), the European Union Seventh Framework Programme FP7/2007-2013 under grant agreement CRISIS-ICT-2011-288501 (CRISIS – Complexity Research Initiative for Systemic InstabilitieS) and mOSAIC 2011-256910 (Open-Source API and Platform for Multiple Clouds). These supports are gratefully acknowledged.

mailto:[email protected]


WEHIA 2012 - Replication of MacroABM 2

LayoutMotivation and BackgroundThe original ModelResults

2012.06.22.


Motivation and Background

2012.06.22.


Replication? Why care?Replication of experiments, validation of

results are essential„Simulations as experiments”

If cannot be reproduced, its scientific value is in question

Models never replicated - except a few classical ones

Helps us get a deeper understandingOf relevant properties, key issuesDeploy simulation as a research tool

2012.06.22.


Validation?Docking – alingment of different models

Different computational models for the same phenomenon

ReplicationW/o being able to replicate results of an

artificial model, how to target real-world systems?

Several problems, e.g. ambiguity Different approaches exist (AgentUML, ODD, etc.) But there’s no consensus on using them...

2012.06.22.


Why to replicate? Parameter sweeps„[...] suppose that in a model there are just 10 relevant parameters, and that each parameter can assume 10 different values (a rather simplifying assumption). As a result, one obtains that the constellation of the parameter space is given by 10^10 vectors. If we perform 20 different runs for each one of them to take into account the possible effects of changing the random seeds, the total number of simulations would amount to 2*10^11!”

2012.06.22.

Gatti, Domenico Delli, Saul Desiderio, Edoardo Gaffeo, Pasquale Cirillo, and Mauro Gallegati:Macroeconomics from the Bottom-up. 1st ed. Springer, 2011 (p. 76., section 3.10.1)


Why to replicate?In a different environment?

Matlab Java/Mason

EfficiencyReduce required time for a single simulation run

Tool support: MEMEParameter sweep explorationBeing Strong

Exploiting Grid/Cloud systemsBeing Smart

Design of Experiments

2012.06.22.


Background“The CRISIS project addresses building a next generation macroeconomic and financial system policymaking model: a bottom-up agent-based simulation that fully accounts for the heterogeneity of households, firms, and government actors. The model will incorporate the latest evidence from behavioral economics in portraying agent behavior, and the CRISIS team will also collect new data on agent decision making using experimental economics techniques. While any model must make simplifying assumptions about human behavior, the CRISIS model will be significantly more realistic in its portrayal of relevant agent behavior than the current generation of policymaking models.”

Crisis project description: https://www.crisis-economics.eu/

2012.06.22.

https://www.crisis-economics.eu/



WEHIA 2012 - Replication of MacroABM 92012.06.22.

Web-based Game

(Participatory Experiments)

Economic Simulator

(Cloud-Based Parameter Sweep

Execution)

Replicated Model

ModellingFramework

Models


The Original Model

2012.06.22.


The Original Model

2012.06.22.

Source: Domenico Delli Gatti, personal communications


AgentsHouseholds

supply laborbuy consumption goodshold deposits

Firmsdemand laborproduce and sell consumption goods

Bankreceive deposits from householdsextend loans to firms

2012.06.22.


Market Processes I1. Fims compute net worth, production/price

and labour demand2. Credit market:

1. Bank decides credit conditions2. Firms decide to whether take loan or not

3. Job market:1. Firms redefine labour demand, publish

vacancies:1. Excess workforce: fire workers2. Insufficient workforce: hire if possible

2012.06.22.


Market Processes II4. Consumption goods market:

1. Workers get wages and compute consumption budget

2. Firms post their price3. Consumers contact z firms randomly

Ordered by price

4. Unspent money Involuntary savings5. Unsold goods Sold at zero cost (non-durable)

5. Accounting1. Firms calculate profits2. Earnings are retained profits

Used to update net worth.2012.06.22.


Results

2012.06.22.


Results I - Benchmarking

2012.06.22.


Result II – VerificationScaled agents (w/o changing overall ratio)

Up to 7500 agentsAvg’d 40 runsT = 1000 time stepsIncluded initial state

High oscillationsUntil spontaneous

order emerges(„equilibrium”)

2012.06.22.

WEHIA 2012 - Replication of MacroABM 182012.06.22.


SummaryWe created a replication the MacroABM model in a

different environmentIdentic outputResults are platform, environment-independentOpens up the window of standardized simulation tools

Extensive parameter space explorations

Performance speedupBy the factor 5x-10xOn the other hand, code length is increased similarly:

Matlab: ~300 LoC Java: 1500 + 1000 LoC

2012.06.22.


Download!

2012.06.22.

http://www.crisis-economics.eu/jmark-i-build-report



Thank you!Richard O. Legendi

[email protected]://people.inf.elte.hu/legendi/

June 22., 2012.

Crsisis Website: http://www.crisis-economics.eu/


http://people.inf.elte.hu/legendi/



http://www.crisis-economics.eu/

http://www.crisis-economics.eu/

Replication of Macroeconomics from the Bottom-up

Technology

Transcript of Replication of Macroeconomics from the Bottom-up