# 1、準(zhǔn)備數(shù)據(jù)
import torch
import pandas as pd
import numpy as np
xy = pd.read_csv('G:/datasets/diabetes/diabetes.csv',dtype=np.float32)?? ?# 文件路徑
x_data = torch.from_numpy(xy.values[:,:-1])
y_data = torch.from_numpy(xy.values[:,[-1]])

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.activate = torch.nn.ReLU()
? ??
? ? def forward(self, x):
? ? ? ? x = self.activate(self.linear1(x))
? ? ? ? x = self.activate(self.linear2(x))
? ? ? ? x = torch.sigmoid(self.linear3(x))
? ? ? ? return x
model = Model()

### 將模型和訓(xùn)練數(shù)據(jù)加載到GPU上
# 模型加載到GPU上
device = torch.device("cuda:0" if torch.cuda.is_available() else "cpu")
model.to(device)
# 數(shù)據(jù)加載到GPU上
x = x_data.to(device)
y = y_data.to(device)

3、構(gòu)造損失函數(shù)和優(yōu)化器
criterion = torch.nn.BCELoss(reduction='mean')
optimizer = torch.optim.SGD(model.parameters(),lr=0.1)

epoch_list = []
loss_list = []
epochs = 10000
for epoch in range(epochs):
? ? # Forward
? ? y_pred = model(x)
? ? loss = criterion(y_pred, y)
? ? print(epoch, loss)

? ? epoch_list.append(epoch)
? ? loss_list.append(loss.data.item())

? ? # Backward
? ? optimizer.zero_grad()
? ? loss.backward()

? ? # Update
? ? optimizer.step()

model.linear1.weight,model.linear1.bias
model.linear2.weight,model.linear2.bias
model.linear3.weight,model.linear3.bias

# 繪圖展示
plt.plot(epoch_list,loss_list,'b')
plt.xlabel('epoch')
plt.ylabel('loss')
plt.grid()
plt.show()

# 準(zhǔn)確率
y_pred_label = torch.where(y_pred.data.cpu() >= 0.5,torch.tensor([1.0]),torch.tensor([0.0]))
acc = torch.eq(y_pred_label, y_data).sum().item()/y_data.size(0)

print("loss = ",loss.item(), "acc = ",acc)

loss = ?0.4232381284236908 acc = ?0.7931488801054019