| import math | |
| import torch | |
| import torch.nn as nn | |
| class SinusoidalPosEmb(nn.Module): | |
| def __init__(self, dim): | |
| super().__init__() | |
| self.dim = dim | |
| def forward(self, x): | |
| device = x.device | |
| half_dim = self.dim // 2 | |
| emb = math.log(10000) / (half_dim - 1) | |
| emb = torch.exp(torch.arange(half_dim, device=device) * -emb) | |
| emb = x[:, None] * emb[None, :] | |
| emb = torch.cat((emb.sin(), emb.cos()), dim=-1) | |
| return emb | |