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@@ -1,221 +0,0 @@
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-import copy
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-from typing import Optional
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-
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-import torch
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-import torch.nn as nn
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-import torch.nn.functional as F
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-from torch import nn, Tensor
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-
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-
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-# ------------------------------- Basic Modules -------------------------------
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-def get_activation(act_type=None):
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- if act_type == 'relu':
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- return nn.ReLU(inplace=True)
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- elif act_type == 'gelu':
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- return nn.GELU()
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- elif act_type == 'lrelu':
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- return nn.LeakyReLU(0.1, inplace=True)
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- elif act_type == 'mish':
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- return nn.Mish(inplace=True)
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- elif act_type == 'silu':
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- return nn.SiLU(inplace=True)
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-
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-
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-def get_norm(norm_type, dim):
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- if norm_type == 'BN':
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- return nn.BatchNorm2d(dim)
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- elif norm_type == 'GN':
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- return nn.GroupNorm(num_groups=32, num_channels=dim)
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- elif norm_type == 'LN':
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- return nn.LayerNorm(dim)
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-
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-
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-def get_clones(module, N):
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- return nn.ModuleList([copy.deepcopy(module) for i in range(N)])
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-
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-
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-def build_multi_head_attention(d_model, num_heads, dropout, attn_type='mhsa'):
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- if attn_type == 'mhsa':
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- attn_layer = MultiHeadAttention(d_model, num_heads, dropout)
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- elif attn_type == 's_mhsa':
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- attn_layer = None
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-
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- return attn_layer
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-
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-
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-# ------------------------------- MLP -------------------------------
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-class MLP(nn.Module):
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- """ Very simple multi-layer perceptron (also called FFN)"""
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-
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- def __init__(self, in_dim, hidden_dim, out_dim, num_layers):
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- super().__init__()
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- self.num_layers = num_layers
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- h = [hidden_dim] * (num_layers - 1)
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- self.layers = nn.ModuleList(nn.Linear(n, k) for n, k in zip([in_dim] + h, h + [out_dim]))
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-
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- def forward(self, x):
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- for i, layer in enumerate(self.layers):
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- x = F.relu(layer(x)) if i < self.num_layers - 1 else layer(x)
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- return x
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-
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-
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-# ------------------------------- Transformer Modules -------------------------------
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-## Vanilla Multi-Head Attention
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-class MultiHeadAttention(nn.Module):
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- def __init__(self, d_model, num_heads, dropout=0.) -> None:
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- super().__init__()
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- # --------------- Basic parameters ---------------
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- self.d_model = d_model
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- self.num_heads = num_heads
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- self.dropout = dropout
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- self.scale = (d_model // num_heads) ** -0.5
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-
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- # --------------- Network parameters ---------------
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- self.q_proj = nn.Linear(d_model, d_model, bias = False) # W_q, W_k, W_v
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- self.k_proj = nn.Linear(d_model, d_model, bias = False) # W_q, W_k, W_v
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- self.v_proj = nn.Linear(d_model, d_model, bias = False) # W_q, W_k, W_v
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-
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- self.out_proj = nn.Linear(d_model, d_model)
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- self.dropout = nn.Dropout(dropout)
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-
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-
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- def forward(self, query, key, value):
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- """
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- Inputs:
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- query : (Tensor) -> [B, Nq, C]
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- key : (Tensor) -> [B, Nk, C]
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- value : (Tensor) -> [B, Nk, C]
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- """
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- bs = query.shape[0]
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- Nq = query.shape[1]
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- Nk = key.shape[1]
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-
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- # ----------------- Input proj -----------------
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- query = self.q_proj(query)
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- key = self.k_proj(key)
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- value = self.v_proj(value)
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-
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- # ----------------- Multi-head Attn -----------------
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- ## [B, N, C] -> [B, N, H, C_h] -> [B, H, N, C_h]
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- query = query.view(bs, Nq, self.num_heads, self.d_model // self.num_heads)
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- query = query.permute(0, 2, 1, 3).contiguous()
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- key = key.view(bs, Nk, self.num_heads, self.d_model // self.num_heads)
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- key = key.permute(0, 2, 1, 3).contiguous()
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- value = value.view(bs, Nk, self.num_heads, self.d_model // self.num_heads)
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- value = value.permute(0, 2, 1, 3).contiguous()
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- # Attention
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- ## [B, H, Nq, C_h] X [B, H, C_h, Nk] = [B, H, Nq, Nk]
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- sim_matrix = torch.matmul(query, key.transpose(-1, -2)) * self.scale
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- sim_matrix = torch.softmax(sim_matrix, dim=-1)
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-
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- # ----------------- Output -----------------
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- out = torch.matmul(sim_matrix, value) # [B, H, Nq, C_h]
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- out = out.permute(0, 2, 1, 3).contiguous().view(bs, Nq, -1)
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- out = self.out_proj(out)
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-
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- return out
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-
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-## Transformer Encoder layer
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-class TREncoderLayer(nn.Module):
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- def __init__(self,
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- d_model,
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- num_heads,
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- dim_feedforward=2048,
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- dropout=0.1,
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- act_type="relu",
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- attn_type='mhsa'
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- ):
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- super().__init__()
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- # Multi-head Self-Attn
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- self.self_attn = build_multi_head_attention(d_model, num_heads, dropout, attn_type)
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-
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- # Feedforwaed Network
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- self.linear1 = nn.Linear(d_model, dim_feedforward)
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- self.dropout = nn.Dropout(dropout)
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- self.linear2 = nn.Linear(dim_feedforward, d_model)
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-
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- self.norm1 = nn.LayerNorm(d_model)
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- self.norm2 = nn.LayerNorm(d_model)
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- self.dropout1 = nn.Dropout(dropout)
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- self.dropout2 = nn.Dropout(dropout)
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-
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- self.activation = get_activation(act_type)
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-
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-
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- def with_pos_embed(self, tensor, pos: Optional[Tensor]):
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- return tensor if pos is None else tensor + pos
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-
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-
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- def forward(self, src, pos):
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- """
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- Input:
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- src: [torch.Tensor] -> [B, N, C]
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- pos: [torch.Tensor] -> [B, N, C]
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- Output:
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- src: [torch.Tensor] -> [B, N, C]
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- """
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- q = k = self.with_pos_embed(src, pos)
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-
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- # self-attn
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- src2 = self.self_attn(q, k, value=src)
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-
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- # reshape: [B, N, C] -> [B, C, H, W]
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- src = src + self.dropout1(src2)
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- src = self.norm1(src)
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-
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- # ffpn
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- src2 = self.linear2(self.dropout(self.activation(self.linear1(src))))
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- src = src + self.dropout2(src2)
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- src = self.norm2(src)
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-
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- return src
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-
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-## Transformer Decoder layer
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-class TRDecoderLayer(nn.Module):
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- def __init__(self, d_model, num_heads, dim_feedforward=2048, dropout=0.1, act_type="relu", attn_type='mhsa'):
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- super().__init__()
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- # Multi-head Self-Attn
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- self.self_attn = build_multi_head_attention(d_model, num_heads, dropout, attn_type)
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- self.cross_attn = build_multi_head_attention(d_model, num_heads, dropout)
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- # Feedforward Network
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- self.linear1 = nn.Linear(d_model, dim_feedforward)
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- self.dropout = nn.Dropout(dropout)
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- self.linear2 = nn.Linear(dim_feedforward, d_model)
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-
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- self.norm1 = nn.LayerNorm(d_model)
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- self.norm2 = nn.LayerNorm(d_model)
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- self.norm3 = nn.LayerNorm(d_model)
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- self.dropout1 = nn.Dropout(dropout)
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- self.dropout2 = nn.Dropout(dropout)
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- self.dropout3 = nn.Dropout(dropout)
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-
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- self.activation = get_activation(act_type)
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-
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-
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- def with_pos_embed(self, tensor, pos: Optional[Tensor]):
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- return tensor if pos is None else tensor + pos
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-
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-
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- def forward(self, tgt, tgt_query_pos, memory, memory_pos):
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- # self attention
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- tgt2 = self.self_attn(
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- query=self.with_pos_embed(tgt, tgt_query_pos),
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- key=self.with_pos_embed(tgt, tgt_query_pos),
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- value=tgt)[0]
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- tgt = tgt + self.dropout1(tgt2)
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- tgt = self.norm1(tgt)
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-
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- # cross attention
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- tgt2 = self.cross_attn(
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- query=self.with_pos_embed(tgt, tgt_query_pos),
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- key=self.with_pos_embed(memory, memory_pos),
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- value=memory)
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- tgt = tgt + self.dropout2(tgt2)
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- tgt = self.norm2(tgt)
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-
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- # ffn
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- tgt2 = self.linear2(self.dropout(self.activation(self.linear1(tgt))))
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- tgt = tgt + self.dropout3(tgt2)
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- tgt = self.norm3(tgt)
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-
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- return tgt
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