diff --git a/numpy-train-study2.py b/numpy-train-study2.py deleted file mode 100644 index 6465a13..0000000 --- a/numpy-train-study2.py +++ /dev/null @@ -1,104 +0,0 @@ -#简单神经网络测试实例 -import numpy as np - -def tanh(x): #双曲函数 - return np.tanh(x) - -def tanh_deriv(x):#更新权重时,需要用到双曲函数的倒数 - return 1.0 - np.tanh(x)*np.tanh(x) - -def logistic(x):#构建逻辑函数 - return 1/(1 + np.exp(-x)) - -def logistic_derivatic(x): #逻辑函数的倒数 - return logistic(x)*(1 - logistic(x)) - -class NeuralNetwork: - def __init__(self,layer,activation='tanh'): - ''' - :param layer:A list containing the number of unit in each layer. - Should be at least two values.每层包含的神经元数目 - :param activation: the activation function to be used.Can be - "logistic" or "tanh" - ''' - if activation == 'logistic': - self.activation = logistic - self.activation_deriv = logistic_derivatic - elif activation == 'tanh': - self.activation = tanh - self.activation_deriv = tanh_deriv - - self.weights = [] - for i in range(1,len(layer) - 1):#权重的设置 - self.weights.append((2*np.random.random((layer[i - 1] + 1,layer[i] + 1))-1)*0.25) - self.weights.append((2*np.random.random((layer[i] + 1,layer[i+1]))-1)*0.25) - '''训练神经网络,通过传入的数据,不断更新权重weights''' - def fit(self,X,y,learning_rate=0.2,epochs=10000): - ''' - :param X: 数据集 - :param y: 数据输出结果,分类标记 - :param learning_rate: 学习率 - :param epochs: 随机抽取的数据的训练次数 - :return: - ''' - X = np.atleast_2d(X) #转化X为np数据类型,试数据类型至少是两维的 - temp = np.ones([X.shape[0],X.shape[1]+1]) - temp[:,0:-1] = X - X = temp - y = np.array(y) - - for k in range(epochs): - i = np.random.randint(X.shape[0]) #随机抽取的行 - a = [X[i]] - - for I in range(len(self.weights)):#完成正向所有的更新 - a.append(self.activation(np.dot(a[I],self.weights[I])))#dot():对应位相乘后相加 - error = y[i] - a[-1] - deltas = [error * self.activation_deriv(a[-1])]#*self.activation_deriv(a[I])#输出层误差 - # 反向更新 - for I in range(len(a) -2,0,-1): - deltas.append(deltas[-1].dot(self.weights[I].T)*self.activation_deriv(a[I])) - deltas.reverse() - for i in range(len(self.weights)): - layer = np.atleast_2d(a[i]) - delta = np.atleast_2d(deltas[i]) - self.weights[i] += learning_rate*layer.T.dot(delta) - - def predict(self,x): - x = np.array(x) - temp = np.ones(x.shape[0] + 1) - temp[0:-1] = x - a = temp - for I in range(0,len(self.weights)): - a = self.activation(np.dot(a,self.weights[I])) - return a #只需要保存最后的值,就是预测出来的值 -nn = NeuralNetwork([2,2,1], 'tanh') -X = np.array([[0, 0], [0, 1], [1, 0], [1, 1]]) -y = np.array([0, 1, 1, 0]) -nn.fit(X, y) -for i in [[0, 0], [0, 1], [1, 0], [1,1]]: - print(i, nn.predict(i)) - -#from sklearn.datasets import load_digits #导入数据集 -#from sklearn.metrics import confusion_matrix,classification_report #对结果的预测的包 -#from sklearn.preprocessing import LabelBinarizer #把数据转化为二维的数字类型 -#from sklearn.cross_validation import train_test_split #可以把数据拆分成训练集与数据集 - -#digits = load_digits() #把数据改成0到1之间 -#X = digits.data -#y = digits.target -#X -= X.min() -#X /= X.max() - -#nn = NeuralNetwork([64,100,10],'logistic') -#X_train,X_test,y_train,y_test = train_test_split(X,y) -#labels_train = LabelBinarizer().fit_transform(y_train) -#labels_test = LabelBinarizer().fit_transform(y_test) -#print("start fitting") -#nn.fit(X_train,labels_train,epochs=3000) -#predictions = [] -#for i in range(X_test.shape[0]): -# o = nn.predict(X_test[i]) -# predictions.append(np.argmax(o)) -#print(confusion_matrix(y_test,predictions)) -#print(classification_report(y_test,predictions)) \ No newline at end of file