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from typing import Optional | |
import torch | |
from torch import nn | |
from torch import nn, Tensor | |
from torch.nn.modules.transformer import _get_activation_fn | |
def add_ml_decoder_head(model): | |
if hasattr(model, 'global_pool') and hasattr(model, 'fc'): # most CNN models, like Resnet50 | |
model.global_pool = nn.Identity() | |
del model.fc | |
num_classes = model.num_classes | |
num_features = model.num_features | |
model.fc = MLDecoder(num_classes=num_classes, initial_num_features=num_features) | |
elif hasattr(model, 'global_pool') and hasattr(model, 'classifier'): # EfficientNet | |
model.global_pool = nn.Identity() | |
del model.classifier | |
num_classes = model.num_classes | |
num_features = model.num_features | |
model.classifier = MLDecoder(num_classes=num_classes, initial_num_features=num_features) | |
elif 'RegNet' in model._get_name() or 'TResNet' in model._get_name(): # hasattr(model, 'head') | |
del model.head | |
num_classes = model.num_classes | |
num_features = model.num_features | |
model.head = MLDecoder(num_classes=num_classes, initial_num_features=num_features) | |
else: | |
print("Model code-writing is not aligned currently with ml-decoder") | |
exit(-1) | |
if hasattr(model, 'drop_rate'): # Ml-Decoder has inner dropout | |
model.drop_rate = 0 | |
return model | |
class TransformerDecoderLayerOptimal(nn.Module): | |
def __init__(self, d_model, nhead=8, dim_feedforward=2048, dropout=0.1, activation="relu", | |
layer_norm_eps=1e-5) -> None: | |
super(TransformerDecoderLayerOptimal, self).__init__() | |
self.norm1 = nn.LayerNorm(d_model, eps=layer_norm_eps) | |
self.dropout = nn.Dropout(dropout) | |
self.dropout1 = nn.Dropout(dropout) | |
self.dropout2 = nn.Dropout(dropout) | |
self.dropout3 = nn.Dropout(dropout) | |
self.multihead_attn = nn.MultiheadAttention(d_model, nhead, dropout=dropout) | |
# Implementation of Feedforward model | |
self.linear1 = nn.Linear(d_model, dim_feedforward) | |
self.linear2 = nn.Linear(dim_feedforward, d_model) | |
self.norm2 = nn.LayerNorm(d_model, eps=layer_norm_eps) | |
self.norm3 = nn.LayerNorm(d_model, eps=layer_norm_eps) | |
self.activation = _get_activation_fn(activation) | |
def __setstate__(self, state): | |
if 'activation' not in state: | |
state['activation'] = torch.nn.functional.relu | |
super(TransformerDecoderLayerOptimal, self).__setstate__(state) | |
def forward(self, tgt: Tensor, memory: Tensor, tgt_mask: Optional[Tensor] = None, | |
memory_mask: Optional[Tensor] = None, | |
tgt_key_padding_mask: Optional[Tensor] = None, | |
memory_key_padding_mask: Optional[Tensor] = None) -> Tensor: | |
tgt = tgt + self.dropout1(tgt) | |
tgt = self.norm1(tgt) | |
tgt2 = self.multihead_attn(tgt, memory, memory)[0] | |
tgt = tgt + self.dropout2(tgt2) | |
tgt = self.norm2(tgt) | |
tgt2 = self.linear2(self.dropout(self.activation(self.linear1(tgt)))) | |
tgt = tgt + self.dropout3(tgt2) | |
tgt = self.norm3(tgt) | |
return tgt | |
# @torch.jit.script | |
# class ExtrapClasses(object): | |
# def __init__(self, num_queries: int, group_size: int): | |
# self.num_queries = num_queries | |
# self.group_size = group_size | |
# | |
# def __call__(self, h: torch.Tensor, class_embed_w: torch.Tensor, class_embed_b: torch.Tensor, out_extrap: | |
# torch.Tensor): | |
# # h = h.unsqueeze(-1).expand(-1, -1, -1, self.group_size) | |
# h = h[..., None].repeat(1, 1, 1, self.group_size) # torch.Size([bs, 5, 768, groups]) | |
# w = class_embed_w.view((self.num_queries, h.shape[2], self.group_size)) | |
# out = (h * w).sum(dim=2) + class_embed_b | |
# out = out.view((h.shape[0], self.group_size * self.num_queries)) | |
# return out | |
class GroupFC(object): | |
def __init__(self, embed_len_decoder: int): | |
self.embed_len_decoder = embed_len_decoder | |
def __call__(self, h: torch.Tensor, duplicate_pooling: torch.Tensor, out_extrap: torch.Tensor): | |
for i in range(self.embed_len_decoder): | |
h_i = h[:, i, :] | |
w_i = duplicate_pooling[i, :, :] | |
out_extrap[:, i, :] = torch.matmul(h_i, w_i) | |
class MLDecoder(nn.Module): | |
def __init__(self, num_classes, num_of_groups=-1, decoder_embedding=768, initial_num_features=2048): | |
super(MLDecoder, self).__init__() | |
embed_len_decoder = 100 if num_of_groups < 0 else num_of_groups | |
if embed_len_decoder > num_classes: | |
embed_len_decoder = num_classes | |
# switching to 768 initial embeddings | |
decoder_embedding = 768 if decoder_embedding < 0 else decoder_embedding | |
self.embed_standart = nn.Linear(initial_num_features, decoder_embedding) | |
# decoder | |
decoder_dropout = 0.1 | |
num_layers_decoder = 1 | |
dim_feedforward = 2048 | |
layer_decode = TransformerDecoderLayerOptimal(d_model=decoder_embedding, | |
dim_feedforward=dim_feedforward, dropout=decoder_dropout) | |
self.decoder = nn.TransformerDecoder(layer_decode, num_layers=num_layers_decoder) | |
# non-learnable queries | |
self.query_embed = nn.Embedding(embed_len_decoder, decoder_embedding) | |
self.query_embed.requires_grad_(False) | |
# group fully-connected | |
self.num_classes = num_classes | |
self.duplicate_factor = int(num_classes / embed_len_decoder + 0.999) | |
self.duplicate_pooling = torch.nn.Parameter( | |
torch.Tensor(embed_len_decoder, decoder_embedding, self.duplicate_factor)) | |
self.duplicate_pooling_bias = torch.nn.Parameter(torch.Tensor(num_classes)) | |
torch.nn.init.xavier_normal_(self.duplicate_pooling) | |
torch.nn.init.constant_(self.duplicate_pooling_bias, 0) | |
self.group_fc = GroupFC(embed_len_decoder) | |
def forward(self, x): | |
if len(x.shape) == 4: # [bs,2048, 7,7] | |
embedding_spatial = x.flatten(2).transpose(1, 2) | |
else: # [bs, 197,468] | |
embedding_spatial = x | |
embedding_spatial_786 = self.embed_standart(embedding_spatial) | |
embedding_spatial_786 = torch.nn.functional.relu(embedding_spatial_786, inplace=True) | |
bs = embedding_spatial_786.shape[0] | |
query_embed = self.query_embed.weight | |
# tgt = query_embed.unsqueeze(1).repeat(1, bs, 1) | |
tgt = query_embed.unsqueeze(1).expand(-1, bs, -1) # no allocation of memory with expand | |
h = self.decoder(tgt, embedding_spatial_786.transpose(0, 1)) # [embed_len_decoder, batch, 768] | |
h = h.transpose(0, 1) | |
out_extrap = torch.zeros(h.shape[0], h.shape[1], self.duplicate_factor, device=h.device, dtype=h.dtype) | |
self.group_fc(h, self.duplicate_pooling, out_extrap) | |
h_out = out_extrap.flatten(1)[:, :self.num_classes] | |
h_out += self.duplicate_pooling_bias | |
logits = h_out | |
return logits | |