/*
 * 
 * MAML TUTORIAL (Model 4.2)  -- The file of the observer unit
 * For full description refer to 
 * http://www.syslab.ceu.hu/maml/tutorial/
 * 
 * 'Segregation' a model by Thomas Schelling
 * 
 * This simulation is based on a model published by T. Schelling, and consists
 * of agents living in a 2d grid. The agents are of two colors (blue and red)
 * and stay at a given location only if the ratio of the number of their 
 * neighbors the same color and the number of neighbors is more than a 
 * specified limit. What is interesting is that if this limit is fairly low
 * (appr. 0.5), this fairly tolerant behaviour leads to surprisingly high 
 * rate of segregation at the global level.
 * It was implemented in MAML v0.03 as part of its tutorial.
 * 
 * (c) 1998, CEU Systems Laboratory
 * 
 */

// Taking the file of the model
$import "m5.maml";

@observe Segregation {
@uses <analysis.h>;			// We need this Swarm package
					// for the 2d graphics display

  // Extending the behavior of the resident (agent)
  // by a routine to draw itself on the display
  // (It is clearly not connected to the model itself,
  // but with its observation only. That's why it is
  // done through the extension mechanism and not
  // coded in the model files. The model should run 
  // without this subroutine!)
  @extendAgent Resident {
    @sub: (void) drawSelfOn: (id) r {
      [r drawPointX: posX Y: posY Color: color];
    }
  }

////////////////////////////////////////////////////////////////////////

// Model variables to be probed
@probe: var "citySize", var "numOfResidents", var "ratio",
        var "minLimit", var "maxLimit", 
        var "minAgeLimit", var "maxAgeLimit",
        var "emptyIsOK";

////////////////////////////////////////////////////////////////////////
 
// Variables of the display
@var: id colormap;		// Color scale
@var: id cityRaster;		// Graphics window
@var: id cityDisplay;		// Utility to draw the residents

// Variable of the observer, which is to be probed
@var: int displayFrequency;
@probe: var "displayFrequency";

////////////////////////////////////////////////////////////////////////

// The observer's schedule
@schedule cyclic (displayFrequency) {	// To be executed according at
					// the frequency set by the variable
  0: @planDef {
       @to cityRaster erase;		// Clear the display
       @to cityDisplay display;		// Use the utility to draw it...
       @to cityRaster drawSelf;		// ... and refresh it on the screen
     }  
}

////////////////////////////////////////////////////////////////////////

// Initialization of the observer
@init:

  // Setting the default values of the parameters
  citySize = 50;
  numOfResidents = 2000;
  ratio = 50;
  minAgeLimit = 0;
  maxAgeLimit = 80;
  minLimit = 0.25;
  maxLimit = 0.70;
  emptyIsOK = true;
  
  displayFrequency = 1;

  // Displaying the probes
  @buildProbes;
  [model probe];
  
  // Stopping the model to let the user change the parameters
  [controlPanel setStateStopped];

  // Initializing the model with the (possibly new) parameters
  @initModel;

  // Creating the observer's graphics gadgets
  @create Colormap colormap;    
  [colormap setColor: 1 ToName: "red"];
  [colormap setColor: 2 ToName: "blue"];

  @create ZoomRaster cityRaster;
  [cityRaster setColormap: colormap];
  [cityRaster setZoomFactor: 6];
  [cityRaster setWidth: citySize Height: citySize];
  [cityRaster setWindowTitle: "Schelling's Segregation City"];
  [cityRaster pack];

  @create Object2dDisplay cityDisplay {
    [cityDisplay setDisplayWidget: cityRaster];
    [cityDisplay setDiscrete2dToDisplay: city];
    [cityDisplay setObjectCollection: groupOfResident];
    [cityDisplay setDisplayMessage: M(drawSelfOn:)];       
  } 
}