optimizer = torch.optim.SGD([{'params':net.parameters() ,'lr':0.1},
                         {'params':net.conv_r1.bias, 'lr':0.0} ], lr=0.1, momentum=0.9)

I use the above code to freeze net.conv_r1.bias, But got:
ValueError: some parameters appear in more than one parameter group

So, what should I do to only freeze net.conv_r1.bias while  train all other params in net
THX!