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Python 用遗传算法求解异或问题_Python_Numpy_Genetic Algorithm_Xor - Fatal编程技术网

Python 用遗传算法求解异或问题

Python 用遗传算法求解异或问题,python,numpy,genetic-algorithm,xor,Python,Numpy,Genetic Algorithm,Xor,我试图用神经网络解决异或问题。为了训练,我使用遗传算法 人口:200 最高世代数:10000 交叉率:0,8 突变率:0.1 重量:9 激活功能:乙状结肠 选择方法:高百分比选择最适合的 代码: 一些输入: XOR是一个简单的问题。通过几百次随机初始化,您应该有一些幸运的人能够立即解决它(如果“已解决”意味着他们在执行阈值后输出是正确的)。这是一个很好的测试,可以查看您的初始化和前馈过程是否正确,而无需一次性调试整个GA。或者你可以手工制作正确的重量和偏差,看看是否有效 你的初始重量(均匀-4

我试图用神经网络解决异或问题。为了训练,我使用遗传算法

人口:200

最高世代数:10000

交叉率:0,8

突变率:0.1

重量:9

激活功能:乙状结肠

选择方法:高百分比选择最适合的

代码:

一些输入:

  • XOR是一个简单的问题。通过几百次随机初始化,您应该有一些幸运的人能够立即解决它(如果“已解决”意味着他们在执行阈值后输出是正确的)。这是一个很好的测试,可以查看您的初始化和前馈过程是否正确,而无需一次性调试整个GA。或者你可以手工制作正确的重量和偏差,看看是否有效
  • 你的初始重量(均匀-40…+40)太大了。我想对于XOR来说,这可能没问题。但初始权值应确保大多数神经元不会饱和,但也不会完全位于乙状结肠的线性区域
  • 在你的实现工作完成后,看看这个神经网络的例子,看看如何用更少的代码来实现它

这就是所有必要的代码吗?你能提供一个吗?这就是我所有的代码,我做了一些更改,就像你说的,现在输出是一致的,但是错误的,总是0 1 1 1 1 1 1 1 0,我找不到错误
    def crossover(self,wfather,wmother):
        r = np.random.random()
        if r <= self.crossover_perc:
            new_weight= self.crossover_perc*wfather+(1-self.crossover_perc)*wmother
            new_weight2=self.crossover_perc*wmother+(1-self.crossover_perc)*wfather
            return new_weight,new_weight2
        else:
            return wfather,wmother

    def select(self,fits):
        percentuais = np.array(fits) / float(sum(fits))
        vet = [percentuais[0]]
        for p in percentuais[1:]:
            vet.append(vet[-1] + p)
        r = np.random.random()
        #print(len(vet), r)
        for i in range(len(vet)):
            if r <= vet[i]:
                return i


    def mutate(self, weight):
        r = np.random.random()
        if r <= self.mut_perc:
            mutr=np.random.randint(self.number_weights)
            weight[mutr] = weight[mutr] + np.random.normal()
        return weight

    def activation_fuction(self, net):
        return 1 / (1 + math.exp(-net))
 def create_initial_population(self):
        population = np.random.uniform(-40, 40, [self.population_size, self.number_weights])  
        return population

    def feedforward(self, inp1, inp2, weights):
        bias = 1
        x = self.activation_fuction(bias * weights[0] + (inp1 * weights[1]) + (inp2 * weights[2]))
        x2 = self.activation_fuction(bias * weights[3] + (inp1 * weights[4]) + (inp2 * weights[5]))
        out = self.activation_fuction(bias * weights[6] + (x * weights[7]) + (x2 * weights[8]))
        print(inp1, inp2, out)
        return out

    def fitness(self, weights):
        y1 = abs(0.0 - self.feedforward(0.0, 0.0, weights))
        y2 = abs(1.0 - self.feedforward(0.0, 1.0, weights))
        y3 = abs(1.0 - self.feedforward(1.0, 0.0, weights))
        y4 = abs(0.0 - self.feedforward(1.0, 1.0, weights))
        error = (y1 + y2 + y3 + y4) ** 2
        # print("Error: ", 1/error)
        return 1 / error

    def sortpopbest(self, pop):
        pop_with_fit = [(weights,self.fitness(weights)) for weights in pop]
        sorted_population=sorted(pop_with_fit, key=lambda weights_fit: weights_fit[1]) #Worst->Best One
        fits = []
        pop = []
        for i in sorted_population:
            pop.append(i[0])
            fits.append(i[1])
        return pop,fits

 def execute(self):
        pop = self.create_initial_population()
        for g in range(self.max_generations):  # maximo de geracoes
            pop, fits = self.sortpopbest(pop)
            nova_pop=[]
            for c in range(int(self.population_size/2)):
                weights =  pop[self.select(fits)]
                weights2 =  pop[self.select(fits)]
                new_weights,new_weights2=self.crossover(weights,weights2)
                new_weights=self.mutate(new_weights)
                new_weights2=self.mutate(new_weights2)
                #print(fits)
                nova_pop.append(new_weights)  # adiciona na nova_pop
                nova_pop.append(new_weights2)
            pop = nova_pop
            print(len(fits),fits)