pytorch 第三课
import torch
import numpy as np
from torch.autograd import Variable
from torch import nn
from torch import optim
import matplotlib.pyplot as plt
x_train = np.array([[3.3], [4.4], [5.5], [6.71], [6.93]], dtype=np.float32)
y_train = np.array([[1.7], [2.76], [2.09], [3.19], [1.694]], dtype=np.float32)
x_train = torch.from_numpy(x_train)
y_train = torch.from_numpy(y_train)
class LinearRegression(nn.Module):
def __init__(self):
super(LinearRegression, self).__init__()
self.linear = nn.Linear(1, 1)
def forward(self, x):
out = self.linear(x)
return out
if torch.cuda.is_available():
model = LinearRegression().cuda()
else:
model = LinearRegression()
criterion = nn.MSELoss()
optimizer = optim.SGD(model.parameters(), lr = 1e-3)
num_epochs = 1000
for epoch in range(num_epochs):
if torch.cuda.is_available():
inputs = Variable(x_train).cuda()
target = Variable(y_train).cuda()
else:
inputs = Variable(x_train)
target = Variable(y_train)
# forward
out = model(inputs)
loss = criterion(out, target)
# backward
optimizer.zero_grad()
loss.backward()
optimizer.step()
if(epoch+1) % 20 == 0:
print('Epoch[{}/{}], loss: {:.6f}'
.format(epoch+1, num_epochs, loss.data[0]))
model.eval() # 测试模型
predict = model(Variable(x_train))
predict = predict.data.numpy()
plt.plot(x_train.numpy(), y_train.numpy(), 'ro', label='Original data')
plt.plot(x_train.numpy(), predict, label='Fitting Line')
plt.show()