PyTorch – Autograd库的使用

自动求梯度

import torch
from torch.autograd import Variable

N, D = 3, 4

x = Variable(torch.randn(N, D)),
         requires_grad=True)
y = Variable(torch.randn(N, D)),
         requires_grad=True)
z = Variable(torch.randn(N, D)),
         requires_grad=True)

a = x * y
b = a + z
c = torch.sum(b)

c.backward()

print(x.grad.data)  # 求梯度
print(y.grad.data)
print(z.grad.data)

import torch

from torch.autograd import Variable

N, D = 3, 4

x = Variable(torch.randn(N, D)),

requires_grad=True)

y = Variable(torch.randn(N, D)),

requires_grad=True)

z = Variable(torch.randn(N, D)),

requires_grad=True)

a = x * y

b = a + z

c = torch.sum(b)

c.backward()

print(x.grad.data) # 求梯度

print(y.grad.data)

print(z.grad.data)