DL之DNN:自定义2层神经网络TwoLayerNet模型(封装为层级结构)利用MNIST数据集进行训练、预测
导读
计算图在神经网络算法中的作用。计算图的节点是由局部计算构成的。局部计算构成全局计算。计算图的正向传播进行一般的计算。通过计算图的反向传播,可以计算各个节点的导数。
目录
输出结果
设计思路
核心代码
输出结果
设计思路
核心代码
class TwoLayerNet:def __init__(self, input_size, hidden_size, output_size, weight_init_std = 0.01):self.params = {}self.params['W1'] = weight_init_std * np.random.randn(input_size, hidden_size)self.params['b1'] = np.zeros(hidden_size)self.params['W2'] = weight_init_std * np.random.randn(hidden_size, output_size) self.params['b2'] = np.zeros(output_size)self.layers = OrderedDict()self.layers['Affine1'] = Affine(self.params['W1'], self.params['b1'])self.layers['Relu1'] = Relu()self.layers['Affine2'] = Affine(self.params['W2'], self.params['b2'])self.lastLayer = SoftmaxWithLoss()def predict(self, x):for layer in self.layers.values():x = layer.forward(x)return x# x:输入数据, t:监督数据def loss(self, x, t):y = self.predict(x)return self.lastLayer.forward(y, t)def accuracy(self, x, t):y = self.predict(x)y = np.argmax(y, axis=1)if t.ndim != 1 : t = np.argmax(t, axis=1)accuracy = np.sum(y == t) / float(x.shape[0])return accuracydef gradient(self, x, t):self.loss(x, t)dout = 1dout = self.lastLayer.backward(dout)layers = list(self.layers.values())layers.reverse()for layer in layers:dout = layer.backward(dout)grads = {}grads['W1'], grads['b1'] = self.layers['Affine1'].dW, self.layers['Affine1'].dbgrads['W2'], grads['b2'] = self.layers['Affine2'].dW, self.layers['Affine2'].dbreturn grads
相关文章
DL之DNN:自定义2层神经网络TwoLayerNet模型(封装为层级结构)利用MNIST数据集进行训练、预测