【PyTorch】RuntimeError: one of the variables needed for gradient computation has been modified by an

错误：

RuntimeError: one of the variables needed for gradient computation has been modified by an inplace operation

报错原因：

import torch
x = torch.FloatTensor([[1., 2.]])
w1 = torch.FloatTensor([[2.], [1.]])
w2 = torch.FloatTensor([3.])
w1.requires_grad = True
w2.requires_grad = True

d = torch.matmul(x, w1)
f = torch.matmul(d, w2)
d[:] = 1 # 因为这句, 代码报错了 RuntimeError: one of the variables needed for gradient computation has been modified by an inplace operation

f.backward()

因为  对于