/*
 * 
 * EDGECITY v1.5 -- The Model's main file
 * 
 * 'Evolution of Central Places' a model by Paul Krugman
 * 
 * This simulation is based on the demo model published by P. Krugman, which was
 * reformulated as an agent-based model by László Gulyás. 
 * It was implemented in MAML v0.03 as an example application.
 * 
 * (c) 1998, CEU Systems Laboratory
 * 
 */

@model EdgeCity {

@var: int NumOfPlaces;	  	     // Number Of Locations
@var: int NumOfFirms;		     // Number Of Agents
@var: double A, B, r1, r2, mobility; // Model Parameters 
                                     // (mobility stands for gamma in the paper)
@var: double initialFlatness;        // Parameter used in the equation for
                                     // the initial distribution (was k in the
                                     // original paper)
@var: int randomMoveFactor;          // Newly introduced parameter (noise)


  // MAML code for the centralized information broker agent
  // which stores the common information available for the agents
  // (note: every agent could calculate it itself through intensive
  // communication, however technically this is a much more elegant
  // version)
  $import "infobank.maml.stub";
  
  // MAML code for the agents (firms)
  $import "firm.maml.stub";


@var: [] int places;                 // Array storing the actual number of
                                     // firms residing at each locations.
@var: InfoBank infoBank;             // Instance of the InfoBroker Agent Class

// The model's schedule which drives the dynamics of it
@schedule cyclic(1) {                // It is a cyclic schedule of the length 1
   0: @planDef seq {                 // This actions are executed for every 
                                     // cycle, exactly in this order
         @forEach groupOfFirm determineMove; // All firms execute 'determineMove'
         @to infoBank updateInformation;     // infoBank updates its contents
   }
}

// Array used in initialization 
// (Technical variable storing the intervals used to determine the initial
// locations of the firms).
@var: [] double initialProb;

// The initialization of the model
@init:
Firm *dummy;                         // Temporaly variables for firm creation
double sum, locValue;                
int i, j;

   // Initializing the locations
   @create [NumOfPlaces:i] int places {
      places[i] = 0;
   }

   // Initializing the firms
   // First, we create random probabilities for the locations 
   // modified by the initialFlatness parameter (as in the paper)
   @create [NumOfPlaces:i] double initialProb {
     initialProb[i] = initialFlatness + 
                      [uniformDblRand 
                        getDoubleWithMin: 0 withMax: 1.0
                      ];
   }
   
   // Then, we create connected intervals out of them
   for (i=1; i<NumOfPlaces; i++) 
     initialProb[i] += initialProb[i-1];
   sum = initialProb[NumOfPlaces-1];
   
   if (sum < 0.0001)                 // For any case, fix if it would be
     sum = 1.0;                      // too small. (getDoubleWithMin:withMax:
                                     // does not like if min == max)

   // Now, let's create the agents       
   for (i=0; i<NumOfFirms; i++) 
      // Here we create of agent
      @create Firm dummy {
      
         // Generate a random point in the connected intervals
         locValue = [uniformDblRand getDoubleWithMin: 0 withMax: sum];
         
         // Determine in which interval it is
         j = 0;
         while ((j < NumOfPlaces) && (initialProb[j] < locValue)) 
           j++;                    
           
         // The corresponding location is the initial place for the agent
         [dummy setLocation: j];
      }   

   // Initializing the central infobank
   @create InfoBank infoBank;
   [infoBank updateInformation];     // Calculate the information, right away
}