代码解释 # Set Dataloader vid_path, vid_writer = None, None if webcam: view_img = True torch.backends.cudnn.benchmark = True # set True to speed up constant image size inference dataset = LoadStreams(source, img_size=imgsz) else: save_img = True dataset = LoadImages(source, img_size=imgsz)

# Dataloader bs = 1 # batch_size if webcam: view_img = check_imshow(warn=True) dataset = LoadStreams(source, img_size=imgsz, stride=stride, auto=pt, vid_stride=vid_stride) bs = len(dataset) elif screenshot: dataset = LoadScreenshots(source, img_size=imgsz, stride=stride, auto=pt) else: dataset = LoadImages(source, img_size=imgsz, stride=stride, auto=pt, vid_stride=vid_stride) vid_path, vid_writer = [None] * bs, [None] * bs

这段代码是YOLOv5中的一部分，用于创建数据加载器。具体来说，它检查是否正在使用网络摄像头或截屏，如果是，则创建适当的数据集加载器。如果不是，则创建一个图像加载器。对于网络摄像头，如果要显示检测结果，则会...

# Dataloader if webcam: show_vid = check_imshow() cudnn.benchmark = True # set True to speed up constant image size inference dataset = LoadStreams(source, img_size=imgsz, stride=stride) nr_sources = len(dataset.sources) else: dataset = LoadImages(source, img_size=imgsz, stride=stride) nr_sources = 1 vid_path, vid_writer, txt_path = [None] * nr_sources, [None] * nr_sources, [None] * nr_sources # initialize StrongSORT cfg = get_config() cfg.merge_from_file(opt.config_strongsort) # Create as many strong sort instances as there are video sources strongsort_list = [] for i in range(nr_sources): strongsort_list.append( StrongSORT( strong_sort_weights, device, half, max_dist=cfg.STRONGSORT.MAX_DIST, max_iou_distance=cfg.STRONGSORT.MAX_IOU_DISTANCE, max_age=cfg.STRONGSORT.MAX_AGE, n_init=cfg.STRONGSORT.N_INIT, nn_budget=cfg.STRONGSORT.NN_BUDGET, mc_lambda=cfg.STRONGSORT.MC_LAMBDA, ema_alpha=cfg.STRONGSORT.EMA_ALPHA,

这段代码是一个数据加载器（Dataloader）的实现。根据webcam变量的取值（True或False），选择不同的数据加载方式。如果webcam为True，则使用LoadStreams类加载视频流数据，设置图像大小为imgsz，采样间隔...

class DistributedSampler(_DistributedSampler): def init(self, dataset, num_replicas=None, rank=None, shuffle=True): super().init(dataset, num_replicas=num_replicas, rank=rank) self.shuffle = shuffle def iter(self): if self.shuffle: g = torch.Generator() g.manual_seed(self.epoch) indices = torch.randperm(len(self.dataset), generator=g).tolist() else: indices = torch.arange(len(self.dataset)).tolist() indices += indices[:(self.total_size - len(indices))] assert len(indices) == self.total_size indices = indices[self.rank:self.total_size:self.num_replicas] assert len(indices) == self.num_samples return iter(indices) def build_dataloader(dataset_cfg, class_names, batch_size, dist, root_path=None, workers=4, seed=None, logger=None, training=True, merge_all_iters_to_one_epoch=False, total_epochs=0): dataset = all[dataset_cfg.DATASET]( dataset_cfg=dataset_cfg, class_names=class_names, root_path=root_path, training=training, logger=logger, ) if merge_all_iters_to_one_epoch: assert hasattr(dataset, 'merge_all_iters_to_one_epoch') dataset.merge_all_iters_to_one_epoch(merge=True, epochs=total_epochs) if dist: if training: sampler = torch.utils.data.distributed.DistributedSampler(dataset) else: rank, world_size = common_utils.get_dist_info() sampler = DistributedSampler(dataset, world_size, rank, shuffle=False) else: sampler = None dataloader = DataLoader( dataset, batch_size=batch_size, pin_memory=True, num_workers=workers, shuffle=(sampler is None) and training, collate_fn=dataset.collate_batch, drop_last=False, sampler=sampler, timeout=0, worker_init_fn=partial(common_utils.worker_init_fn, seed=seed) ) return dataset, dataloader, sampler

这段代码是一个用于构建数据加载器的函数。它接受一些参数，包括数据集的配置、类别名称、批次大小、分布式训练标志、数据集的根路径等。首先，根据数据集的配置和其他参数，创建一个数据集对象。如果设置了 ...

LDAM损失函数pytorch代码如下：class LDAMLoss(nn.Module): def init(self, cls_num_list, max_m=0.5, weight=None, s=30): super(LDAMLoss, self).init() m_list = 1.0 / np.sqrt(np.sqrt(cls_num_list)) m_list = m_list * (max_m / np.max(m_list)) m_list = torch.cuda.FloatTensor(m_list) self.m_list = m_list assert s > 0 self.s = s if weight is not None: weight = torch.FloatTensor(weight).cuda() self.weight = weight self.cls_num_list = cls_num_list def forward(self, x, target): index = torch.zeros_like(x, dtype=torch.uint8) index_float = index.type(torch.cuda.FloatTensor) batch_m = torch.matmul(self.m_list[None, :], index_float.transpose(1,0)) # 0,1 batch_m = batch_m.view((16, 1)) # size=(batch_size, 1) (-1,1) x_m = x - batch_m output = torch.where(index, x_m, x) if self.weight is not None: output = output * self.weight[None, :] target = torch.flatten(target) # 将 target 转换成 1D Tensor logit = output * self.s return F.cross_entropy(logit, target, weight=self.weight) 模型部分参数如下：# 设置全局参数 model_lr = 1e-5 BATCH_SIZE = 16 EPOCHS = 50 DEVICE = torch.device('cuda:0' if torch.cuda.is_available() else 'cpu') use_amp = True use_dp = True classes = 7 resume = None CLIP_GRAD = 5.0 Best_ACC = 0 #记录最高得分 use_ema=True model_ema_decay=0.9998 start_epoch=1 seed=1 seed_everything(seed) # 数据增强 mixup mixup_fn = Mixup( mixup_alpha=0.8, cutmix_alpha=1.0, cutmix_minmax=None, prob=0.1, switch_prob=0.5, mode='batch', label_smoothing=0.1, num_classes=classes) # 读取数据集 dataset_train = datasets.ImageFolder('/home/adminis/hpy/ConvNextV2_Demo/RAF-DB/RAF/train', transform=transform) dataset_test = datasets.ImageFolder("/home/adminis/hpy/ConvNextV2_Demo/RAF-DB/RAF/valid", transform=transform_test)# 导入数据 train_loader = torch.utils.data.DataLoader(dataset_train, batch_size=BATCH_SIZE, shuffle=True,drop_last=True) test_loader = torch.utils.data.DataLoader(dataset_test, batch_size=BATCH_SIZE, shuffle=False) 帮我用pytorch实现模型在模型训练中使用LDAM损失函数

好的，以下是使用LDAM损失函数训练模型的Pytorch代码： python import torch import torch.nn as nn import torch.nn.functional as F import numpy as np from torchvision import datasets, transforms from ...

解释下面代码含义def show_batch(display_transform=None): if display_transform is None: display_transform = transforms.ToTensor() display_set = torchvision.datasets.CIFAR10( root='./' + data_folder, train=True, download=True, transform=display_transform ) display_loader = torch.utils.data.DataLoader(display_set, batch_size=32) topil = transforms.ToPILImage() for batch_img, batch_label in display_loader: grid = make_grid(batch_img, nrow=8) grid_img = topil(grid) plt.figure(figsize=(10, 10)) plt.imshow(grid_img) grid_img.save('./img/trans_cifar10.png') plt.show() break

具体来说，它实例化了一个 torchvision.datasets.CIFAR10 数据集对象，对该数据集进行了预处理（可选参数 display_transform），然后使用 torch.utils.data.DataLoader 创建了一个数据加载器，每次从中取出 32...

pytorch部分代码如下：class LDAMLoss(nn.Module): def init(self, cls_num_list, max_m=0.5, weight=None, s=30): super(LDAMLoss, self).init() m_list = 1.0 / np.sqrt(np.sqrt(cls_num_list)) m_list = m_list * (max_m / np.max(m_list)) m_list = torch.cuda.FloatTensor(m_list) self.m_list = m_list assert s > 0 self.s = s if weight is not None: weight = torch.FloatTensor(weight).cuda() self.weight = weight self.cls_num_list = cls_num_list def forward(self, x, target): index = torch.zeros_like(x, dtype=torch.uint8) index_float = index.type(torch.cuda.FloatTensor) batch_m = torch.matmul(self.m_list[None, :], index_float.transpose(0,1)) batch_m = batch_m.view((-1, 1)) # size=(batch_size, 1) (-1,1) x_m = x - batch_m output = torch.where(index, x_m, x) if self.weight is not None: output = output * self.weight[None, :] logit = output * self.s return F.cross_entropy(logit, target, weight=self.weight) train_loader = torch.utils.data.DataLoader(dataset_train, batch_size=BATCH_SIZE, shuffle=True,drop_last=True) test_loader = torch.utils.data.DataLoader(dataset_test, batch_size=BATCH_SIZE, shuffle=True) cls_num_list = np.zeros(classes) for , label in train_loader.dataset: cls_num_list[label] += 1 criterion_train = LDAMLoss(cls_num_list=cls_num_list, max_m=0.5, s=30) criterion_val = LDAMLoss(cls_num_list=cls_num_list, max_m=0.5, s=30) mixup_fn = Mixup( mixup_alpha=0.8, cutmix_alpha=1.0, cutmix_minmax=None, prob=0.1, switch_prob=0.5, mode='batch', label_smoothing=0.1, num_classes=classes) for batch_idx, (data, target) in enumerate(train_loader): data, target = data.to(device, non_blocking=True), Variable(target).to(device,non_blocking=True) # 3、将数据输入mixup_fn生成mixup数据 samples, targets = mixup_fn(data, target) targets = torch.tensor(targets).to(torch.long) # 4、将上一步生成的数据输入model，输出预测结果，再计算loss output = model(samples) # 5、梯度清零（将loss关于weight的导数变成0） optimizer.zero_grad() # 6、若使用混合精度 if use_amp: with torch.cuda.amp.autocast(): # 开启混合精度 loss = torch.nan_to_num(criterion_train(output, targets)) # 计算loss scaler.scale(loss).backward() # 梯度放大 torch.nn.utils.clip_grad_norm(model.parameters(), CLIP_GRAD) # 梯度裁剪，防止梯度爆炸 scaler.step(optimizer) # 更新下一次迭代的scaler scaler.update() # 否则，直接反向传播求梯度 else: loss = criterion_train(output, targets) loss.backward() torch.nn.utils.clip_grad_norm_(model.parameters(), CLIP_GRAD) optimizer.step() 报错：RuntimeError: Expected index [112, 1] to be smaller than self [16, 7] apart from dimension 1

这个报错是因为在计算batch_m时，index_float的维度是反过来的，应该将index_...batch_m = torch.matmul(self.m_list[None, :], index_float.transpose(1,0)) ... 你可以尝试修改后再运行看看是否还会出现报错。

修改一下这段代码在pycharm中的实现，import pandas as pd import numpy as np from sklearn.model_selection import train_test_split import torch import torch.nn as nn import torch.nn.functional as F import torch.optim as optim #from torchvision import datasets,transforms import torch.utils.data as data #from torch .nn:utils import weight_norm import matplotlib.pyplot as plt from sklearn.metrics import precision_score from sklearn.metrics import recall_score from sklearn.metrics import f1_score from sklearn.metrics import cohen_kappa_score data_ = pd.read_csv(open(r"C:\Users\zhangjinyue\Desktop\rice.csv"),header=None) data_ = np.array(data_).astype('float64') train_data =data_[:,:520] train_Data =np.array(train_data).astype('float64') train_labels=data_[:,520] train_labels=np.array(train_data).astype('float64') train_data,train_data,train_labels,train_labels=train_test_split(train_data,train_labels,test_size=0.33333) train_data=torch.Tensor(train_data) train_data=torch.LongTensor(train_labels) train_data=train_data.reshape(-1,1,20,26) train_data=torch.Tensor(train_data) train_data=torch.LongTensor(train_labels) train_data=train_data.reshape(-1,1,20,26) start_epoch=1 num_epoch=1 BATCH_SIZE=70 Ir=0.001 classes=('0','1','2','3','4','5') device=torch.device("cuda"if torch.cuda.is_available()else"cpu") torch.backends.cudnn.benchmark=True best_acc=0.0 train_dataset=data.TensorDataset(train_data,train_labels) test_dataset=data.TensorDataset(train_data,train_labels) train_loader=torch.utills.data.DataLoader(dtaset=train_dataset,batch_size=BATCH_SIZE,shuffle=True) test_loader=torch.utills.data.DataLoader(dtaset=train_dataset,batch_size=BATCH_SIZE,shuffle=True)

torch.backends.cudnn.benchmark = True best_acc = 0.0 train_dataset = data.TensorDataset(train_data, train_labels) test_dataset = data.TensorDataset(train_data, train_labels) train_loader = torch....

def prep_dataloader(path, mode, batch_size, n_jobs=0, target_only=False, mu=None, std=None): #训练集不需要传mu,std, 所以默认值设置为None ''' Generates a dataset, then is put into a dataloader. ''' dataset = COVID19Dataset(path, mu, std, mode=mode, target_only=target_only) # Construct dataset if mode == 'train': #如果是训练集，把训练集上均值和方差保存下来 mu = dataset.mu std = dataset.std dataloader = DataLoader( dataset, batch_size, shuffle=(mode == 'train'), drop_last=False, num_workers=n_jobs, pin_memory=True) # Construct dataloader return dataloader, mu, std

这段代码用于生成数据集并将其放入一个数据加载器（dataloader）中。函数的输入参数包括数据集的路径（path）、模式（mode，训练集、开发集或测试集）、批量大小（batch_size）、工作线程数（n_jobs，默认为0，表示...

def get_train_loader(engine, dataset, s3client=None): data_setting = {'img_root': config.img_root_folder, 'gt_root': config.gt_root_folder, 'hha_root':config.hha_root_folder, 'mapping_root': config.mapping_root_folder, 'train_source': config.train_source, 'eval_source': config.eval_source} train_preprocess = TrainPre(config.image_mean, config.image_std) train_dataset = dataset(data_setting, "train", train_preprocess, config.batch_size * config.niters_per_epoch, s3client=s3client) train_sampler = None is_shuffle = True batch_size = config.batch_size if engine.distributed: train_sampler = torch.utils.data.distributed.DistributedSampler( train_dataset) batch_size = config.batch_size // engine.world_size is_shuffle = False train_loader = data.DataLoader(train_dataset, batch_size=batch_size, num_workers=config.num_workers, drop_last=True, shuffle=is_shuffle, pin_memory=True, sampler=train_sampler) return train_loader, train_sampler这段代码是什么意思

这段代码是一个函数，作用是返回一个用于训练的数据加载器和采样器。函数接收三个参数：engine表示训练引擎，dataset表示加载数据的数据集，s3client是一个用于访问AWS S3的客户端对象。函数内部会根据不同的参数...

这段代码中加一个test loss功能 class LSTM(nn.Module): def init(self, input_size, hidden_size, num_layers, output_size, batch_size, device): super().init() self.device = device self.input_size = input_size self.hidden_size = hidden_size self.num_layers = num_layers self.output_size = output_size self.num_directions = 1 # 单向LSTM self.batch_size = batch_size self.lstm = nn.LSTM(self.input_size, self.hidden_size, self.num_layers, batch_first=True) self.linear = nn.Linear(65536, self.output_size) def forward(self, input_seq): h_0 = torch.randn(self.num_directions * self.num_layers, self.batch_size, self.hidden_size).to(self.device) c_0 = torch.randn(self.num_directions * self.num_layers, self.batch_size, self.hidden_size).to(self.device) output, _ = self.lstm(input_seq, (h_0, c_0)) pred = self.linear(output.contiguous().view(self.batch_size, -1)) return pred if name == 'main': # 加载已保存的模型参数 saved_model_path = '/content/drive/MyDrive/危急值/model/dangerous.pth' device = 'cuda:0' lstm_model = LSTM(input_size=1, hidden_size=64, num_layers=1, output_size=3, batch_size=256, device='cuda:0').to(device) state_dict = torch.load(saved_model_path) lstm_model.load_state_dict(state_dict) dataset = ECGDataset(X_train_df.to_numpy()) dataloader = DataLoader(dataset, batch_size=256, shuffle=True, num_workers=0, drop_last=True) loss_fn = nn.CrossEntropyLoss() optimizer = optim.SGD(lstm_model.parameters(), lr=1e-4) for epoch in range(200000): print(f'epoch:{epoch}') lstm_model.train() epoch_bar = tqdm(dataloader) for x, y in epoch_bar: optimizer.zero_grad() x_out = lstm_model(x.to(device).type(torch.cuda.FloatTensor)) loss = loss_fn(x_out, y.long().to(device)) loss.backward() epoch_bar.set_description(f'loss:{loss.item():.4f}') optimizer.step() if epoch % 100 == 0 or epoch == epoch - 1: torch.save(lstm_model.state_dict(), "/content/drive/MyDrive/危急值/model/dangerous.pth") print("权重成功保存一次")

以下是加入 Test Loss 功能后的代码： python import torch import torch.nn as nn import torch.optim as optim from torch.utils.data import DataLoader class LSTM(nn.Module): def __init__(self, input_...

class Trainer(object): def init(self, model, optim, device, train_dataloader, val_dataloader, test_dataloader, opt_da=None, discriminator=None, experiment=None, alpha=1, **config): self.model = model self.optim = optim self.device = device self.epochs = config["SOLVER"]["MAX_EPOCH"] self.current_epoch = 0 self.train_dataloader = train_dataloader self.val_dataloader = val_dataloader self.test_dataloader = test_dataloader self.is_da = config["DA"]["USE"] self.alpha = alpha self.n_class = config["DECODER"]["BINARY"]怎么理解

这段代码定义了一个训练器（Trainer）类，并初始化了一些变量和参数，包括神经网络模型、优化器、设备、训练、验证、测试数据集以及一些其他配置参数。同时，还包括一个可选参数discriminator和experiment，以及一个...

def minibatch_set(feature, label, BATCH_SIZE, SHUFFLE): # feature = torch.from_numpy(feature) feature_tensor = torch.tensor(feature, dtype=torch.float32) # label = torch.from_numpy(label) label_tensor = torch.tensor(label, dtype=torch.float32) dataset = Data.TensorDataset(feature_tensor, label_tensor) loader = Data.DataLoader( dataset=dataset, # torch TensorDataset format batch_size=BATCH_SIZE, # mini batch size shuffle=SHUFFLE, # random shuffle for training drop_last=True, #当你的整个数据长度不能够整除你的batchsize，选择是否要丢弃最后一个不完整的batch，默认为False。 num_workers=0) return loader

这个函数minibatch_set是一个用于创建小批量数据集的函数。它使用PyTorch中的DataLoader和TensorDataset来实现。函数接受四个参数： - feature：特征数据，可以是一个Numpy数组。 - label：标签数据，...

def eval_model(model ,eval_dataloader, ckpt_path=None): if ckpt_path: ckpt = torch.load(ckpt_path, map_location='cpu') not_load = model.load_state_dict(ckpt, strict=True) print("not load: ", not_load) model.eval() all_right_num = 0 with torch.no_grad(): for images, labels in eval_dataloader: #images = images.reshape((-1, 1 * 28 * 28)) images = images labels = labels output = model(images) pre = output.max(1, keepdim=True)[1].reshape(labels.shape) right_num = (pre == labels).sum() all_right_num += right_num per = all_right_num / len(eval_dataloader.dataset) print("per is {:.2f}%".format(per.cpu().item() * 100)) return per

这段代码是用于评估模型性能的函数。它接收一个模型、一个评估数据加载器和一个检查点路径作为输入。如果提供了检查点路径，则加载模型的参数。然后，将模型设置为评估模式，然后使用 torch.no_grad() 上下文管理...

YOLOv4中dataloader的get_random_data模块参数详解

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资源摘要信息:"本资源为Python库的压缩包文件，全名为ml-dataloader-*.*.*.*.tar.gz，下载自pypi官网。该库名为ml-dataloader，版本为*.*.*.*。标签为Python库，说明这是一款用Python编写的库。" 1. 关于PyPI： ...

代码解释 # Set Dataloader vid_path, vid_writer = None, None if webcam: view_img = True torch.backends.cudnn.benchmark = True # set True to speed up constant image size inference dataset = LoadStreams(source, img_size=imgsz) else: save_img = True dataset = LoadImages(source, img_size=imgsz)

代码解释# Set Dataloader vid_path, vid_writer = None, None if webcam: view_img = True torch.backends.cudnn.benchmark = True # set True to speed up constant image size inference dataset = LoadStreams(source, img_size=imgsz) else: save_img = True dataset = LoadImages(source, img_size=imgsz)

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代码解释 # Set Dataloader vid_path, vid_writer = None, None if webcam: view_img = True torch.backends.cudnn.benchmark = True # set True to speed up constant image size inference dataset = LoadStreams(source, img_size=imgsz) else: save_img = True dataset = LoadImages(source, img_size=imgsz)

代码解释# Set Dataloader vid_path, vid_writer = None, None if webcam: view_img = True torch.backends.cudnn.benchmark = True # set True to speed up constant image size inference dataset = LoadStreams(source, img_size=imgsz) else: save_img = True dataset = LoadImages(source, img_size=imgsz)

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