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Example using PSO

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Optimising dimensions of a box

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  1. // Example of using the class Pso
  2.  
  3. // Here we are optimising dimensions of a box so that neither
  4. // of the side lenghes exceeds some limit
  5.  
  6.  
  7. //    ____________
  8. //   /           /|
  9. //  /___________/ |
  10. //  |           | |  Volume = a*b*c
  11. //  |           | |  a < limit, b < limit, c < limit
  12. //  |           | |
  13. //  |           | |
  14. //  |___________|/
  15.  
  16.  
  17. #include"partswarmopt.h"
  18. #include <iostream>
  19. #include <fstream>
  20.  
  21. string createInputFile();
  22.  
  23. int main()
  24. {
  25. 	string inpFileName = createInputFile();
  26.  
  27. 	vector<int> position; // for debugging
  28.  
  29. 	ofstream fout("output.txt", ios::out);
  30. 	const unsigned int n_part = 10; // number of particles
  31. 	const unsigned int n_gen = 200; // number of generations
  32.  
  33. 	Pso box(inpFileName, n_part);
  34. 	box.initialize();
  35. 	for (unsigned int i = 0; i < n_gen - 1; i++)
  36. 	{
  37. 		box++;
  38. 		fout << box;
  39.  
  40. 		// The code below is usefull for debugging purposes only
  41. 		for (unsigned int i = 1; i <= n_part; i++)
  42. 		{
  43. 			position = box.currentPosition(i);
  44. 			fout << "Position of particle " << i << ": ";
  45. 			for (int j = 0; j < position.size(); j++)
  46. 			{
  47. 				fout << position[j] << " ";
  48. 			}
  49. 			fout << endl;
  50. 		}
  51. 		fout << "Current best position: ";
  52. 		position = box.bestPosision();
  53. 		for (unsigned int i = 0; i < 3; i++)
  54. 		{
  55. 			fout << position[i] << " ";
  56. 		}
  57. 		fout << endl << endl << endl;
  58. 	}
  59. 	// system("pause");
  60. 	return 0;
  61. }
  62.  
  63.  
  64. double udm::Objective(const vector<double>& parameterValues)
  65. { // Volume of a box = a*b*c
  66. 	double ans = 1;
  67. 	for (unsigned int i = 0; i < parameterValues.size(); i++)
  68. 	{
  69. 		ans *= parameterValues[i];
  70. 	}
  71. 	return -ans;
  72. }
  73.  
  74. vector<double> udm::Constraints(const vector<double>& parameterValues)
  75. { // Box sides' lengthes are limited
  76. 	double limit = 14;
  77. 	vector<double> ans;
  78. 	double penalty;
  79. 	if (parameterValues[0] > limit)
  80. 	{
  81. 		penalty = (parameterValues[0] - limit) / (parameterValues[0] + limit);
  82. 		ans.push_back(penalty);
  83. 	}
  84.  
  85. 	if (parameterValues[1] > limit)
  86. 	{
  87. 		penalty = (parameterValues[1] - limit) / (parameterValues[1] + limit);
  88. 		ans.push_back(penalty);
  89. 	}
  90.  
  91. 	if (parameterValues[2] > limit)
  92. 	{
  93. 		penalty = (parameterValues[2] - limit) / (parameterValues[2] + limit);
  94. 		ans.push_back(penalty);
  95. 	}
  96.  
  97. 	return ans;
  98. }
  99.  
  100. string createInputFile()
  101. { // Creates file with possible side lengthes
  102. 	string filename = "boxsides.txt";
  103. 	ofstream file(filename, ios::out);
  104.  
  105. 	for (int j = 1; j <= 3; j++)
  106. 	{
  107. 		file << 20 << endl;
  108. 		for (int i = 0; i < 20; i++)
  109. 		{
  110. 			file << (i + 1)*2 << " ";
  111. 		}
  112. 		file << endl;
  113. 	}
  114. 	return filename;
  115. }

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