反向传播算法1)

 When neuron j is located in the output layer of the network, it is supplied with a desired response of its own. If neuron j is in the first hidden layer of the netork, then the index i refers to the ith input terminal of the network, for which we write y_i(n)=x_i(n), where x_i(n) is the ith element of the input vector(pattern).