diff --git a/NSGA2-ZDT3.py b/NSGA2-ZDT3.py new file mode 100644 index 0000000..c2a4a22 --- /dev/null +++ b/NSGA2-ZDT3.py @@ -0,0 +1,278 @@ +import math +import random +import matplotlib.pyplot as plt +import copy + + +# 用的是ZDT3测试函数 + +# First function to optimize +def function1(x): + return x[0] + + +# Second function to optimize +def function2(x): + gx = funcationG(x) + value = 1 - math.sqrt(x[0] / gx) - x[0] / gx * math.sin(10 * math.pi * x[0]) + return gx * value + + +def funcationG(x): + sumX = 0 + for i in range(1, varNum): + sumX = sumX + x[i] + return 1 + (9 * sumX) / (varNum - 1) + + +# Function to find index of list +def index_of(a, list): + for i in range(0, len(list)): + if list[i] == a: + return i + return -1 + + +# Function to sort by values +def sort_by_values(list1, values): + sorted_list = [] + while (len(sorted_list) != len(list1)): + if index_of(min(values), values) in list1: + sorted_list.append(index_of(min(values), values)) + values[index_of(min(values), values)] = math.inf + return sorted_list + + +# Function to carry out NSGA-II's fast non dominated sort +def fast_non_dominated_sort(values1, values2): + S = [[] for i in range(0, len(values1))] # 解所支配的集合 + front = [[]] # 排序结果 + n = [0 for i in range(0, len(values1))] # 支配者数量 + rank = [0 for i in range(0, len(values1))] + + for p in range(0, len(values1)): + S[p] = [] + n[p] = 0 + for q in range(0, len(values1)): + if (values1[p] < values1[q] and values2[p] < values2[q]) or ( + values1[p] <= values1[q] and values2[p] < values2[q]) or ( + values1[p] < values1[q] and values2[p] <= values2[q]): + if q not in S[p]: + S[p].append(q) + elif (values1[q] < values1[p] and values2[q] < values2[p]) or ( + values1[q] <= values1[p] and values2[q] < values2[p]) or ( + values1[q] < values1[p] and values2[q] <= values2[p]): + n[p] = n[p] + 1 + if n[p] == 0: + rank[p] = 0 + if p not in front[0]: + front[0].append(p) + + i = 0 + while (front[i] != []): + Q = [] + for p in front[i]: + for q in S[p]: + n[q] = n[q] - 1 + if (n[q] == 0): + rank[q] = i + 1 + if q not in Q: + Q.append(q) + i = i + 1 + front.append(Q) + + del front[len(front) - 1] + return front + + +# Function to calculate crowding distance 拥挤度距离计算 +def crowding_distance(values1, values2, front): + distance = [0 for i in range(0, len(front))] + + sorted1 = sort_by_values(front, values1[:]) + sorted2 = sort_by_values(front, values2[:]) + + distance[0] = math.inf + distance[len(front) - 1] = math.inf + + for k in range(1, len(front) - 1): + distance[k] = distance[k] + (values1[sorted1[k + 1]] - values1[sorted1[k - 1]]) / (max(values1) - min(values1)) + + for k in range(1, len(front) - 1): + distance[k] = distance[k] + (values2[sorted2[k + 1]] - values2[sorted2[k - 1]]) / (max(values2) - min(values2)) + + return distance + + +# 二进制交叉 +def crossover(individuala, individualb, a, b): + individual1 = copy.deepcopy(individuala) + individual2 = copy.deepcopy(individualb) + + for j in range(min(a, b), max(a, b) + 1): + u = random.random() + if u < 0.5: + r = (2 * u) ** (1 / (NC + 1)) + else: + r = (1 / (2 * (1 - u))) ** (1 / (NC + 1)) + individual1[j] = 0.5 * ((1 + r) * individual1[j] + (1 - r) * individual2[j]) + individual2[j] = 0.5 * ((1 - r) * individual1[j] + (1 + r) * individual2[j]) + + individual1[j] = 1 if individual1[j] > 1 else individual1[j] # 此处需要修改为常量 + individual2[j] = 1 if individual2[j] > 1 else individual2[j] + + individual1[j] = 0 if individual1[j] < 0 else individual1[j] + individual2[j] = 0 if individual2[j] < 0 else individual2[j] + return individual1, individual2 + + +# 多项式变异 +def mutation(individual, a): + individualTemp = copy.deepcopy(individual) + u = random.random() + if u < 0.5: + r = (2 * u) ** (1 / (NM + 1)) - 1 + else: + r = (1 - (2 * (1 - u))) ** (1 / (NM + 1)) + + individualTemp[a] = individualTemp[a] + r + + individualTemp[a] = 1 if individualTemp[a] > 1 else individualTemp[a] # 此处需要修改为常量 + individualTemp[a] = 0 if individualTemp[a] < 0 else individualTemp[a] + return individualTemp + + +# 使用此函数之前要确保非支配排序解中都按照拥挤度排序过了 +def competition(non_dominated_sorted, numOfSelect): + selectionResult = [] + non_dominated_sortedTemp = [] + for i in range(0, len(non_dominated_sorted)): + for j in range(0, len(non_dominated_sorted[i])): + non_dominated_sortedTemp.append(non_dominated_sorted[i][j]) + + while len(selectionResult) < numOfSelect: + selections = [random.randint(0, popSize - 1) for i in range(0, popSize // 2)] + selectionResult.append(non_dominated_sortedTemp[min(selections)]) + + return selectionResult + + +min_x = 0 +max_x = 1 # x1 属于[0,1] +varNum = 30 # xi 中i的最大个数 +popSize = 100 # 种群个数 +max_gen = 500 # 最大迭代次数 +pc = 0.9 # 交叉 +pm = 0.01 # 变异 +NC = 20 +NM = 20 + +# 初始化种群 +solution = [] +for i in range(0, popSize): + solution.append([random.random() for j in range(0, varNum)]) + +times = 0 +non_dominated_sorted_solution = [] +function1_values = [] +function2_values = [] + +while times < max_gen: + # 计算种群中,每个个体的两个目标函数值 + function1_values = [function1(solution[i]) for i in range(0, popSize)] + function2_values = [function2(solution[i]) for i in range(0, popSize)] + + # 快速非支配排序 + non_dominated_sorted_solution = fast_non_dominated_sort(function1_values[:], function2_values[:]) + + # 计算拥挤度 + crowding_distance_values = [] + for i in range(0, len(non_dominated_sorted_solution)): + crowding_distance_values.append( + crowding_distance(function1_values[:], function2_values[:], non_dominated_sorted_solution[i][:])) + + # 按照拥挤度排序 + for i in range(0, len(non_dominated_sorted_solution)): + non_dominated_sorted_solution2_1 = [ + index_of(non_dominated_sorted_solution[i][j], non_dominated_sorted_solution[i]) for j in + range(0, len(non_dominated_sorted_solution[i]))] + front22 = sort_by_values(non_dominated_sorted_solution2_1[:], crowding_distance_values[i][:]) # 按照拥挤度排序 + non_dominated_sorted_solution[i] = [non_dominated_sorted_solution[i][front22[j]] for j in + range(0, len(non_dominated_sorted_solution[i]))] + non_dominated_sorted_solution[i].reverse() # 翻转之后是从大到小排序,拥挤度 + + solution2 = copy.deepcopy(solution) + + # 竞标赛选取 + offSpring = competition(non_dominated_sorted_solution, popSize) + # 交叉 + for i in range(0, len(offSpring) // 2): + rc = random.random() + if (rc < pc): + index1 = random.randint(0, varNum - 1) + index2 = random.randint(0, varNum - 1) + while index1 == index2: + index1 = random.randint(0, varNum - 1) + indi1, indi2 = crossover(solution[offSpring[i]], solution[offSpring[len(offSpring) - i - 1]], index1, + index2) + solution2.append(indi1) + solution2.append(indi2) + # 变异 + for i in range(0, len(offSpring)): + rm = random.random() + if rm < pm: + indexOfM = random.randint(0, varNum - 1) + muIndi = mutation(solution[offSpring[i]], indexOfM) + solution2.append(muIndi) + + # 计算函数值 + lengthOfSolution2 = len(solution2) + function1_values2 = [function1(solution2[i]) for i in range(0, lengthOfSolution2)] + function2_values2 = [function2(solution2[i]) for i in range(0, lengthOfSolution2)] + + # 非支配快速排序 + non_dominated_sorted_solution2 = fast_non_dominated_sort(function1_values2[:], function2_values2[:]) + + # 计算拥挤度 + crowding_distance_values2 = [] + for i in range(0, len(non_dominated_sorted_solution2)): + crowding_distance_values2.append( + crowding_distance(function1_values2[:], function2_values2[:], non_dominated_sorted_solution2[i][:])) + + # 产生新的种群 + new_solution = [] + for i in range(0, len(non_dominated_sorted_solution2)): + non_dominated_sorted_solution2_1 = [ + index_of(non_dominated_sorted_solution2[i][j], non_dominated_sorted_solution2[i]) for j in + range(0, len(non_dominated_sorted_solution2[i]))] + front22 = sort_by_values(non_dominated_sorted_solution2_1[:], crowding_distance_values2[i][:]) # 按照拥挤度排序 + front = [non_dominated_sorted_solution2[i][front22[j]] for j in + range(0, len(non_dominated_sorted_solution2[i]))] + front.reverse() # 翻转之后是从大到小排序,拥挤度 + for value in front: + new_solution.append(value) + if (len(new_solution) == popSize): + break + if (len(new_solution) == popSize): + break + solution = [solution2[i] for i in new_solution] + times = times + 1 + print('This is ', times, '\n') + +# Lets plot the final front now +minF1 = [] +minF2 = [] +for k in non_dominated_sorted_solution[0]: + minF1.append(function1_values[k]) + minF2.append(function2_values[k]) + +# 打印第一层 +print("The best front for Generation number ", times, " is") +for valuez in non_dominated_sorted_solution[0]: + print(solution[valuez:], end=" ") +print("\n") + +plt.xlabel('F 1', fontsize=15) +plt.ylabel('F 2', fontsize=15) +plt.scatter(minF1, minF2) +plt.show()