神经网络可以近似任何连续函数 一、反向传播backpropagation (一)反向传播backpropagation 例子1 节点 例子2 patterns in backward flow gradients add at branches (二)高维矩阵反向传播 雅可比矩阵Jacobian matrix 例子 (三)模块化设计 前向传播和反向传播API 以乘法门为例 二、神经网络 Neural Network ...
如果f(x)=Ax (A\in R^{m\times n}, x\in R^{n\times 1}),由于函数返回一个 m 行1列的向量,因此不能对 f 求梯度矩阵。 根据定义,很容易得到以下性质:\nabla_x(f(x)+g(x))=\nabla_xf(x)+\nabla_xg(x)有了上述知识,我们来举个例子: 定义函数f:R^m\rightarrow R, f(z)=z^Tz,那么...
nn = NeuralNetwork(2, 2, 2, hidden_layer_weights=[0.15, 0.2, 0.25, 0.3], hidden_layer_bias=0.35, output_layer_weights=[0.4, 0.45, 0.5, 0.55], output_layer_bias=0.6) for i in range(10000): nn.train([0.05, 0.1], [0.01, 0.09]) print(i, round(nn.calculate_total_error([[[0.05...
nn = NeuralNetwork(2, 2, 2, hidden_layer_weights=[0.15, 0.2, 0.25, 0.3], hidden_layer_bias=0.35, output_layer_weights=[0.4, 0.45, 0.5, 0.55], output_layer_bias=0.6) for i in range(10000): nn.train([0.05, 0.1], [0.01, 0.09]) print(i, round(nn.calculate_total_error([[[0.05...
稳重使用的是sigmoid激活函数,实际还有几种不同的激活函数可以选择,具体的可以参考文献[3],最后推荐一个在线演示神经网络变化的网址:http://www.emergentmind.com/neural-network,可以自己填输入输出,然后观看每一次迭代权值的变化,很好玩~如果有错误的或者不懂的欢迎留言:)...
1#coding:utf-82importrandom3importmath45#6# 参数解释:7#"pd_":偏导的前缀8#"d_":导数的前缀9#"w_ho":隐含层到输出层的权重系数索引10#"w_ih":输入层到隐含层的权重系数的索引1112classNeuralNetwork:13LEARNING_RATE=0.51415def__init__(self,num_inputs,num_hidden,num_outputs,hidden_layer_weights...
Our aim is still the same as was in last post viz;we want to manipulate the values of our ...
back propagation neural network dehazinghaze-free imagehazy imageslearningscene radiancesingle image dehazingAtmospheric modelingBy using the A356 aluminum alloy (Al–7Si–0.3Mg) with dispersed eutectic silicon particles and the single-phase Al–1Si–0.3Mg alloy, this study was carried out to ...
结果: image.png 公式 输出层: CodeCogsEqn(15).gif 隐藏层: CodeCogsEqn(14).gif 最后用一张网上的图来总结: WechatIMG435.jpeg 参考: http://www.hankcs.com/ml/back-propagation-neural-network.html
network outputs the correct result. Note that the neural network's output is assumed to be the index of whichever neuron in the final layer has the highest activation."""test_results=[(np.argmax(self.feedforward(x)),y)for(x,y)intest_data]returnsum(int(x==y)for(x,y...