Python是一種高級(jí)編程語言,用于開發(fā)各種應(yīng)用程序。在Python中,輪盤賭算法是一種常見的遺傳算法,用于優(yōu)化問題的求解。該算法模仿自然選擇過程,不斷進(jìn)化和改進(jìn)結(jié)果,直到獲得最優(yōu)解。
import random import numpy as np # 定義適應(yīng)度函數(shù) def fitnessFunction(x): return x**2 # 初始化種群 def initializePopulation(popSize, genomeSize): population = [] for i in range(popSize): genome = [] for j in range(genomeSize): genome.append(random.randint(0, 1)) population.append(genome) return population # 計(jì)算每個(gè)個(gè)體的適應(yīng)度 def calculateFitness(population): fitnessValues = [] for genome in population: decodedGenome = 0 for i in range(len(genome)): decodedGenome += genome[i] * 2**i decodedGenome = (decodedGenome / (2**len(genome)-1)) * 10 fitness = fitnessFunction(decodedGenome) fitnessValues.append(fitness) return fitnessValues # 選擇操作 def selection(population, fitnessValues, numParents): parents = [] for i in range(numParents): parents.append(population[np.argmax(fitnessValues)]) fitnessValues[np.argmax(fitnessValues)] = -1 return parents # 交叉操作 def crossover(parents): offspring = [] for i in range(len(parents)): offspring.append(parents[i]) for i in range(0, len(parents), 2): point = random.randint(1, len(parents[i])-1) offspring[i][:point] = parents[i+1][:point] offspring[i+1][:point] = parents[i][:point] return offspring # 變異操作 def mutation(offspring, mutationRate): for i in range(len(offspring)): for j in range(len(offspring[i])): if random.random()< mutationRate: offspring[i][j] = 1 - offspring[i][j] return offspring # 輪盤賭遺傳算法 def rouletteWheelGA(popSize, genomeSize, numParents=2, numGenerations=50, mutationRate=0.01): population = initializePopulation(popSize, genomeSize) for i in range(numGenerations): fitnessValues = calculateFitness(population) parents = selection(population, fitnessValues, numParents) offspring = crossover(parents) offspring = mutation(offspring, mutationRate) population = parents + offspring return population # 實(shí)現(xiàn)輪盤賭遺傳算法 popSize = 50 genomeSize = 5 numParents = 2 numGenerations = 50 mutationRate = 0.01 population = rouletteWheelGA(popSize, genomeSize, numParents, numGenerations, mutationRate) print("Final population:") for genome in population: print(genome, "Fitness:", fitnessFunction(np.dot(genome, [16, 8, 4, 2, 1])))
在 Python 中使用輪盤賭算法非常容易,只需要定義適應(yīng)度函數(shù)、種群的初始化函數(shù)、選擇、交叉和變異操作,就可以完成輪盤賭遺傳算法的實(shí)現(xiàn)。這種算法可以用于解決各種優(yōu)化問題,如機(jī)器學(xué)習(xí)、數(shù)據(jù)分析和計(jì)算機(jī)視覺等領(lǐng)域。