Improving LoRA: Implementing Weight-Decomposed Low-Rank Adaptation (DoRA) from Scratch
LoRA
LoRA初始化时,A使用正态分布,B使用0.
class LoRALayer(nn.Module):
def __init__(self, in_dim, out_dim, rank, alpha):
super().__init__()
std_dev = 1 / torch.sqrt(torch.tensor(rank).float())
self.A = nn.Parameter(torch.randn(in_dim, rank) * std_dev)
self.B = nn.Parameter(torch.zeros(rank, out_dim))
self.alpha = alpha
def forward(self, x):
x = self.alpha * (x @ self.A @ self.B