ant.cpp

vrpsd -tabu搜索求解！！！！！！！！！！！！！！！！！！！！！！！

#include "Ant.h"

Ant::Ant() {
  currentSolution = NULL;
  fitness = INT_MAX;
}

Ant::Ant( Random* rnd, Control_acs& control, Problem* problem) {
  // no customer visited yet
  //
  for (int i=0; i < problem->numberOfCustomers; i++) {
    customer_served.push_back(false);
  }

  // initialize all tauij and piij values
  //
  tauij = new double[problem->numberOfCustomers];
  piij = new double[problem->numberOfCustomers];
  for (int i=0; i < problem->numberOfCustomers; i++) {
    tauij[i] = 0.0;
    piij[i] = 0.0;
  }
  roulette = new double[problem->numberOfCustomers];

  // build a starting solution
  // using the randomized farthest insertion heuristic
  //
  currentSolution = new Solution( rnd, control, problem);
  randomizedFarthestInsertion(rnd, *currentSolution);
  (*currentSolution).computeExpectedCost();
}

int Ant::solutionStep(int step, int source, Random* rnd, Control_acs& control, Problem* problem, double** pheromoneMatrix) {

  double divisor = 0.0;
  double pij = 0.0;
  double q = rnd->next();

  customer_served[source] = true;

  // Calculate Tauij for fixed source i and all possible destinations j still to be served
  //
  double alfa = control.getALPHA();
  for (int j=0; j < problem->numberOfCustomers; j++) {
    if (! customer_served[j]) {
      if (alfa = 1.0) {
	tauij[j] = pheromoneMatrix[source][j];
      }
      else {
	tauij[j] = pow (pheromoneMatrix[source][j],alfa);
      }
      divisor += tauij[j];
    }
  }
  for (int j=0; j < problem->numberOfCustomers; j++) {
    if (! customer_served[j]) {
      roulette[j] = ( tauij[j] / divisor);
    }
  }
  
  for (int i=0; i < problem->numberOfCustomers; i++) {
    if (! customer_served[i]) {
      pij += roulette[i];
    }
    if (q < pij) {
      // customer i is the next one
      return (i);
    }
  }
}

Ant::~Ant() {
  delete currentSolution;
}