Introduction to Computational Modeling of Social Systems
Prof. Lars-Erik CedermanCenter for Comparative and International Studies (CIS)
Seilergraben 49, Room G.2, [email protected] Weidmann, CIS Room E.3, [email protected]
http://www.icr.ethz.ch/teaching/compmodels
Lecture, January 11, 2005
RePast Tutorial IV
2
Today’s agenda
• More on the GUI mode…– Probes– How to create property descriptors– How to create custom actions
• Introducing the batch mode– How to use parameters and parameter
files– How to collect data
• ExperIPD
3
Probes
• Probes allow the user to view and manipulate single agents
• Require the display surface to be “probeable”
• Variables become available through introspection using the get-set-methods (with set-methods necessary for changes)
4
How to create property descriptors
• To adjust parameters at startup or when the simulation is paused
• Can be applied to both models and agents
• Setup through the pre-defined descriptors variable of SimpleModel
5
How to create property descriptors (cont.)
• Drop-down list:public void setup() { super.setup();
Hashtable h1 = new Hashtable(); h1.put(new Integer(0), "Von Neumann"); h1.put(new Integer(1), "Moore"); ListPropertyDescriptor pd = new ListPropertyDescriptor("Type", h1); descriptors.put("Type", pd);}
public void setType(int type) { this.type = type;}
6
How to create property descriptors (cont.)
• Numerical slider:
public void setup() { super.setup();
RangePropertyDescriptor d = new RangePropertyDescriptor("NumAgents", 10, 100, 20); descriptors.put("NumAgents", d);}
public void setNumAgents(int numAgents) { this.numAgents = numAgents;}
7
How to create custom actions
• Modify the simulation while it is running
• Setup through modelManipulator variable of SimpleModel
• Works for buttons, check boxes, sliders, and arbitrary Java components
8
How to create custom actions (cont.)
• modelManipulator.addButton("Clear Space", new ActionListener() { public void actionPerformed(ActionEvent e){ space.clear(); }});
• modelManipulator.addSlider("Slider", 0, 100, 10, new SliderListener());
• modelManipulator.addCheckBox("Show/Hide", new CheckBoxListener(), false);
• modelManipulator.addComponent(Component c);
9
Failed invasion of TFT in ALLD-World
ALLD
ALLD ALLD ALLD
ALLD
TFT
ALLD ALLD
ALLD3
3
3
3 84
4
4
4+4+4+8 4
= 5.0
3+3+3+3 4
= 3.0
ALLD:
TFT:
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Successful invasion of two TFT players in ALLD-World
ALLD
ALLD ALLD ALLD
ALLD
TFT
ALLD ALLD
TFT
4+4+4+8 4
= 5.0
3+3+3+12 4
= 5.25
ALLD:
TFT:
ALLD
ALLD
ALLD3
3
3
12 123
3
3 84
4
4
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Further spread of TFT players in ALLD-World
TFT
ALLD TFT TFT
ALLD
TFT
TFT TFT
TFT
ALLD
ALLD
TFT
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Separating GUI and batch modes
Modelextends
SimpleModel
ModelGUIextendsModel
ModelBatchextendsModel
ExperIPDGraphIPD,GridIPD
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Subclassing a batch model
class Model extends SimpleModel { model variables
setup()
buildModel()
step()
main()}
class ModelBatch extends Model{ Batch variables (data recorder)
setup() { super.setup(); params = ... }
buildModel() { super.buildModel(); create data recorder }
step() { super.step(); record data }
main() { init.loadModel(m, "params.txt", true); }}
Parameter file
Batch mode
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How to use parameters
• Different purpose depending on context:– Batch mode: allow variables to be
changed through parameter files– GUI mode: show the variables in the
control panelpublic void setup() { super.setup(); params = {"NumPlayers", "PALLC", "PTFT", "PATFT", "PALLD", "PAdapt"};}
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How to use parameters (cont.)
• Requires accessor methods:
public void setup() { super.setup(); params = {"Variable", ...}}
public double getVariable() { return value;}
public void setVariable(double value) { this.value = value;}
Setters only required to
allow modification
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How to use parameter files
• Different effects depending on context:– GUI mode: set initial values– Batch mode: allow to run sweeps
• Usually defined in a file named params.txt
• Runs the simulation with values of 10, 20, and 30:
runs: 1Variable { start: 10 end: 30 incr: 10}
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How to use parameter files (cont.)
• Multiple parameters:
• Nestingruns: 10Food { start: 10 end: 30 incr: 10}
MaxAge { start: 10 end: 30 incr: 10}
runs: 1Food { start: 10 end: 30 incr: 10 { runs: 10 MaxAge { start: 0 end: 40 incr: 1 } }}
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How to use parameter files (cont.)
• Additional keywords:– set
defines a single numerical value as a constant for the entire collection of batch runs.
– set_booleandefines a boolean value (true / false).
– set_stringdefines a string value (without any white space).
– set_list,set_boolean_list, set_string_list define a space-separated list of values. A batch simulation will iterate through the list.
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How to collect data
• Recording of simulation states to:– archive simulation runs– further process the data into third-party
packages (e.g. Excel, Stata, SPSS, SAS, ...)
• Output format: Text files (comma, space or tab delimited)
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How to collect data (cont’d)
• Prepare for the measurements in buildModel()• Determine the duration of the simulations:
setStoppingTime(n);
• Create the data recorder with output to file data.txt:recorder = new DataRecorder(“./data.txt”,this);
• Add numeric streams using introspection:recorder.createNumericaDataSource(“X”,this,”computeX”);
• The output can be formatted with x number of digits before the decimal point, and y after…createNumericaDataSource(“X”,this,”computeX”,x,y);
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How to collect data (cont’d)
• Using introspection requires a method delivering the values
• It is also possible to use inner classes (see the Repast How-To Documentation)
• The data recorder has to be told to record and to write the data to file:recorder.record();
recorder.writeToFile();
• The user can change the data delimiter:recorder.setDelimiter(“ “);
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Typical output fileTimestamp: May 31, 2004 6:09:01 PM
Neighborhood: 0
NumOfTimeSteps: 200
PALLC: 0.25
PALLD: 0.25
PATFT: 0.25
PAdapt: 0.2
PTFT: 0.25
WorldSize: 16
"run" "tick" "Topology" "RngSeed" "ALLC" "TFT" "ATFT" "ALLD" "Payoff"
1 200.0 0 1 0.0 256.0 0.0 0.0 3.0000
2 200.0 0 2 0.0 256.0 0.0 0.0 3.0000
3 200.0 0 3 0.0 256.0 0.0 0.0 3.0000
4 200.0 0 4 0.0 256.0 0.0 0.0 3.0000
…
59 200.0 2 19 0.0 0.0 0.0 256.0 1.0000
60 200.0 2 20 0.0 0.0 0.0 256.0 1.0000
End Time: May 31, 2004 6:09:16 PM
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Replication results (N = 200)
0 6020 40
Number ofTFT-dominatedruns
Initial numberof TFT players
