使用dataloader加载糖尿病数据集~

最新推荐文章于 2024-08-09 14:27:24 发布

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最新推荐文章于 2024-08-09 14:27:24 发布

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分类专栏： pytorch学习

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本文介绍了如何使用PyTorch实现糖尿病数据集的预处理、数据加载，并构建一个包含三个隐藏层的神经网络模型进行预测。通过一步步讲解，读者将学会使用DataLoader进行数据迭代和模型训练，以及BCELoss函数的应用。

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import torch
from torch.utils.data import Dataset
from torch.utils.data import DataLoader

import numpy as np

class DiabetesDataset(Dataset):
    def __init__(self, filepath):
        xy = np.loadtxt(filepath, delimiter=',', dtype=np.float32)
        self.len = xy.shape[0]
        self.x_data = torch.from_numpy(xy[:, :-1])
        self.y_data = torch.from_numpy(xy[:, [-1]])
    def __getitem__(self, index):
        return self.x_data[index], self.y_data[index] #返回元组
    def __len__(self):
        return self.len

dataset = DiabetesDataset('diabetes.csv')
print(len(dataset))
train_loader = DataLoader(dataset=dataset,
                          batch_size=10,
                          shuffle=True,
                          num_workers=0)#num_works并行化，然而windows下只能为0

class Model(torch.nn.Module):
    def __init__(self):
        super(Model, self).__init__()
        self.linear1 = torch.nn.Linear(8, 6)
        self.linear2 = torch.nn.Linear(6, 4)
        self.linear3 = torch.nn.Linear(4, 1)
        self.sigmoid = torch.nn.Sigmoid()
    def forward(self, x):
        x = self.sigmoid(self.linear1(x))
        x = self.sigmoid(self.linear2(x))
        x = self.sigmoid(self.linear3(x))
        return x

model = Model()
criterion = torch.nn.BCELoss(reduction='mean')
optimizer = torch.optim.SGD(model.parameters(), lr=0.01)

for epoch in range(100):
    for i, data in enumerate(train_loader, 0):
        # 1. Prepare data
        inputs, labels = data #自动转成tensor
        # 2. Forward
        y_pred = model(inputs)
        loss = criterion(y_pred, labels)
        print(epoch, i, loss.item())
        # 3. Backward
        optimizer.zero_grad()
        loss.backward()
        # 4. Update
        optimizer.step()