邱锡鹏著 《神经网络与深度学习》案例与实践实验1-5中所需的nndl包

import paddle import paddle.nn.functional as F #新增RunnerV2类 class RunnerV2(object): def __init__(self, model, optimizer, metric, loss_fn): self.model = model self.optimizer = optimizer self.loss_fn = loss_fn self.metric = metric #记录训练过程中的评价指标变化情况 self.train_scores = [] self.dev_scores = [] #记录训练过程中的损失函数变化情况 self.train_loss = [] self.dev_loss = [] def train(self, train_set, dev_set, **kwargs): #传入训练轮数，如果没有传入值则默认为0 num_epochs = kwargs.get("num_epochs", 0) #传入log打印频率，如果没有传入值则默认为100 log_epochs = kwargs.get("log_epochs", 100) #传入模型保存路径，如果没有传入值则默认为"best_model.pdparams" save_path = kwargs.get("save_path", "best_model.pdparams") #梯度打印函数，如果没有传入则默认为"None" print_grads = kwargs.get("print_grads", None) #记录全局最优指标 best_score = 0 #进行num_epochs轮训练 for epoch in range(num_epochs): X, y = train_set #获取模型预测 logits = self.model(X) #计算交叉熵损失 trn_loss = self.loss_fn(logits, y).item() self.train_loss.append(trn_loss) #计算评价指标 trn_score = self.metric(logits, y).item() self.train_scores.append(trn_score) #计算参数梯度 self.model.backward(y) if print_grads is not None: #打印每一层的梯度 print_grads(self.model) #更新模型参数 self.optimizer.step() dev_score, dev_loss = self.evaluate(dev_set) #如果当前指标为最优指标，保存该模型 if dev_score > best_score: self.save_model(save_path) print(f"best accuracy performence has been updated: {best_score:.5f} --> {dev_score:.5f}") best_score = dev_score if epoch % log_epochs == 0: print(f"[Train] epoch: {epoch}, loss: {trn_loss}, score: {trn_score}") print(f"[Dev] epoch: {epoch}, loss: {dev_loss}, score: {dev_score}") def evaluate(self, data_set): X, y = data_set #计算模型输出 logits = self.model(X) #计算损失函数 loss = self.loss_fn(logits, y).item() self.dev_loss.append(loss) #计算评价指标 score = self.metric(logits, y).item() self.dev_scores.append(score) return score, loss def predict(self, X): return self.model(X) def save_model(self, save_path): paddle.save(self.model.params, save_path) def load_model(self, model_path): self.model.params = paddle.load(model_path) class RunnerV3(object): def __init__(self, model, optimizer, loss_fn, metric, **kwargs): self.model = model self.optimizer = optimizer self.loss_fn = loss_fn self.metric = metric # 只用于计算评价指标 # 记录训练过程中的评价指标变化情况 self.dev_scores = [] # 记录训练过程中的损失函数变化情况 self.train_epoch_losses = [] # 一个epoch记录一次loss self.train_step_losses = [] # 一个step记录一次loss self.dev_losses = [] # 记录全局最优指标 self.best_score = 0 def train(self, train_loader, dev_loader=None, **kwargs): # 将模型切换为训练模式 self.model.train() # 传入训练轮数，如果没有传入值则默认为0 num_epochs = kwargs.get("num_epochs", 0) # 传入log打印频率，如果没有传入值则默认为100 log_steps = kwargs.get("log_steps", 100) # 评价频率 eval_steps = kwargs.get("eval_steps", 0) # 传入模型保存路径，如果没有传入值则默认为"best_model.pdparams" save_path = kwargs.get("save_path", "best_model.pdparams") custom_print_log = kwargs.get("custom_print_log", None) # 训练总的步数 num_training_steps = num_epochs * len(train_loader) if eval_steps: if self.metric is None: raise RuntimeError('Error: Metric can not be None!') if dev_loader is None: raise RuntimeError('Error: dev_loader can not be None!') # 运行的step数目 global_step = 0 # 进行num_epochs轮训练 for epoch in range(num_epochs): # 用于统计训练集的损失 total_loss = 0 for step, data in enumerate(train_loader): X, y = data # 获取模型预测 logits = self.model(X) loss = self.loss_fn(logits, y) # 默认求mean total_loss += loss # 训练过程中，每个step的loss进行保存 self.train_step_losses.append((global_step,loss.item())) if log_steps and global_step%log_steps==0: print(f"[Train] epoch: {epoch}/{num_epochs}, step: {global_step}/{num_training_steps}, loss: {loss.item():.5f}") # 梯度反向传播，计算每个参数的梯度值 loss.backward() if custom_print_log: custom_print_log(self) # 小批量梯度下降进行参数更新 self.optimizer.step() # 梯度归零 self.optimizer.clear_grad() # 判断是否需要评价 if eval_steps>0 and global_step>0 and \ (global_step%eval_steps == 0 or global_step==(num_training_steps-1)): dev_score, dev_loss = self.evaluate(dev_loader, global_step=global_step) print(f"[Evaluate] dev score: {dev_score:.5f}, dev loss: {dev_loss:.5f}") # 将模型切换为训练模式 self.model.train() # 如果当前指标为最优指标，保存该模型 if dev_score > self.best_score: self.save_model(save_path) print(f"[Evaluate] best accuracy performence has been updated: {self.best_score:.5f} --> {dev_score:.5f}") self.best_score = dev_score global_step += 1 # 当前epoch 训练loss累计值 trn_loss = (total_loss / len(train_loader)).item() # epoch粒度的训练loss保存 self.train_epoch_losses.append(trn_loss) print("[Train] Training done!") # 模型评估阶段，使用'paddle.no_grad()'控制不计算和存储梯度 @paddle.no_grad() def evaluate(self, dev_loader, **kwargs): assert self.metric is not None # 将模型设置为评估模式 self.model.eval() global_step = kwargs.get("global_step", -1) # 用于统计训练集的损失 total_loss = 0 # 重置评价 self.metric.reset() # 遍历验证集每个批次 for batch_id, data in enumerate(dev_loader): X, y = data # 计算模型输出 logits = self.model(X) # 计算损失函数 loss = self.loss_fn(logits, y).item() # 累积损失 total_loss += loss # 累积评价 self.metric.update(logits, y) dev_loss = (total_loss/len(dev_loader)) dev_score = self.metric.accumulate() # 记录验证集loss if global_step!=-1: self.dev_losse