# coding: utf-8 import sys, os sys.path.append(os.pardir) # 为了导入父目录的文件而进行的设定 import pickle import numpy as np from collections import OrderedDict from common.layers import * from common.gradient import numerical_gradient class SimpleConvNet: """简单的ConvNet conv - relu - pool - affine - relu - affine - softmax Parameters ---------- input_size : 输入大小(MNIST的情况下为784) hidden_size_list : 隐藏层的神经元数量的列表(e.g. [100, 100, 100]) output_size : 输出大小(MNIST的情况下为10) activation : 'relu' or 'sigmoid' weight_init_std : 指定权重的标准差(e.g. 0.01) 指定'relu'或'he'的情况下设定“He的初始值” 指定'sigmoid'或'xavier'的情况下设定“Xavier的初始值” """ def __init__(self, input_dim=(1, 28, 28), conv_param={'filter_num':30, 'filter_size':5, 'pad':0, 'stride':1}, hidden_size=100, output_size=10, weight_init_std=0.01): filter_num = conv_param['filter_num'] filter_size = conv_param['filter_size'] filter_pad = conv_param['pad'] filter_stride = conv_param['stride'] input_size = input_dim[1] conv_output_size = (input_size - filter_size + 2*filter_pad) / filter_stride + 1 pool_output_size = int(filter_num * (conv_output_size/2) * (conv_output_size/2)) # 初始化权重 self.params = {} self.params['W1'] = weight_init_std * \ np.random.randn(filter_num, input_dim[0], filter_size, filter_size) self.params['b1'] = np.zeros(filter_num) self.params['W2'] = weight_init_std * \ np.random.randn(pool_output_size, hidden_size) self.params['b2'] = np.zeros(hidden_size) self.params['W3'] = weight_init_std * \ np.random.randn(hidden_size, output_size) self.params['b3'] = np.zeros(output_size) # 生成层 self.layers = OrderedDict() self.layers['Conv1'] = Convolution(self.params['W1'], self.params['b1'], conv_param['stride'], conv_param['pad']) self.layers['Relu1'] = Relu() self.layers['Pool1'] = Pooling(pool_h=2, pool_w=2, stride=2) self.layers['Affine1'] = Affine(self.params['W2'], self.params['b2']) self.layers['Relu2'] = Relu() self.layers['Affine2'] = Affine(self.params['W3'], self.params['b3']) self.last_layer = SoftmaxWithLoss() def predict(self, x): for layer in self.layers.values(): x = layer.forward(x) return x def loss(self, x, t): """求损失函数 参数x是输入数据、t是教师标签 """ y = self.predict(x) return self.last_layer.forward(y, t) def accuracy(self, x, t, batch_size=100): if t.ndim != 1 : t = np.argmax(t, axis=1) acc = 0.0 for i in range(int(x.shape[0] / batch_size)): tx = x[i*batch_size:(i+1)*batch_size] tt = t[i*batch_size:(i+1)*batch_size] y = self.predict(tx) y = np.argmax(y, axis=1) acc += np.sum(y == tt) return acc / x.shape[0] def numerical_gradient(self, x, t): """求梯度(数值微分) Parameters ---------- x : 输入数据 t : 教师标签 Returns ------- 具有各层的梯度的字典变量 grads['W1']、grads['W2']、...是各层的权重 grads['b1']、grads['b2']、...是各层的偏置 """ loss_w = lambda w: self.loss(x, t) grads = {} for idx in (1, 2, 3): grads['W' + str(idx)] = numerical_gradient(loss_w, self.params['W' + str(idx)]) grads['b' + str(idx)] = numerical_gradient(loss_w, self.params['b' + str(idx)]) return grads def gradient(self, x, t): """求梯度(误差反向传播法) Parameters ---------- x : 输入数据 t : 教师标签 Returns ------- 具有各层的梯度的字典变量 grads['W1']、grads['W2']、...是各层的权重 grads['b1']、grads['b2']、...是各层的偏置 """ # forward self.loss(x, t) # backward dout = 1 dout = self.last_layer.backward(dout) layers = list(self.layers.values()) layers.reverse() for layer in layers: dout = layer.backward(dout) # 设定 grads = {} grads['W1'], grads['b1'] = self.layers['Conv1'].dW, self.layers['Conv1'].db grads['W2'], grads['b2'] = self.layers['Affine1'].dW, self.layers['Affine1'].db grads['W3'], grads['b3'] = self.layers['Affine2'].dW, self.layers['Affine2'].db return grads def save_params(self, file_name="params.pkl"): params = {} for key, val in self.params.items(): params[key] = val with open(file_name, 'wb') as f: pickle.dump(params, f) def load_params(self, file_name="params.pkl"): with open(file_name, 'rb') as f: params = pickle.load(f) for key, val in params.items(): self.params[key] = val for i, key in enumerate(['Conv1', 'Affine1', 'Affine2']): self.layers[key].W = self.params['W' + str(i+1)] self.layers[key].b = self.params['b' + str(i+1)]