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modeling_pretrain.py
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modeling_pretrain.py
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import math
import torch
import torch.nn as nn
import torch.nn.functional as F
import torch.utils.checkpoint as checkpoint
from functools import partial
from modeling_finetune import Block, _cfg, PatchEmbed, get_sinusoid_encoding_table
from timm.models.registry import register_model
from timm.models.layers import trunc_normal_ as __call_trunc_normal_
def trunc_normal_(tensor, mean=0., std=1.):
__call_trunc_normal_(tensor, mean=mean, std=std, a=-std, b=std)
__all__ = [
'pretrain_videomae_small_patch16_224',
'pretrain_videomae_base_patch16_224',
'pretrain_videomae_large_patch16_224',
'pretrain_videomae_huge_patch16_224',
]
class PretrainVisionTransformerEncoder(nn.Module):
""" Vision Transformer with support for patch or hybrid CNN input stage
"""
def __init__(self, img_size=224, patch_size=16, in_chans=3, num_classes=0, embed_dim=768, depth=12,
num_heads=12, mlp_ratio=4., qkv_bias=False, qk_scale=None, drop_rate=0., attn_drop_rate=0.,
drop_path_rate=0., norm_layer=nn.LayerNorm, init_values=None, tubelet_size=2, use_checkpoint=False,
use_learnable_pos_emb=False):
super().__init__()
self.num_classes = num_classes
self.num_features = self.embed_dim = embed_dim # num_features for consistency with other models
self.patch_embed = PatchEmbed(
img_size=img_size, patch_size=patch_size, in_chans=in_chans, embed_dim=embed_dim,tubelet_size=tubelet_size)
num_patches = self.patch_embed.num_patches
self.use_checkpoint = use_checkpoint
# TODO: Add the cls token
if use_learnable_pos_emb:
self.pos_embed = nn.Parameter(torch.zeros(1, num_patches + 1, embed_dim))
else:
# sine-cosine positional embeddings
self.pos_embed = get_sinusoid_encoding_table(num_patches, embed_dim)
dpr = [x.item() for x in torch.linspace(0, drop_path_rate, depth)] # stochastic depth decay rule
self.blocks = nn.ModuleList([
Block(
dim=embed_dim, num_heads=num_heads, mlp_ratio=mlp_ratio, qkv_bias=qkv_bias, qk_scale=qk_scale,
drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[i], norm_layer=norm_layer,
init_values=init_values)
for i in range(depth)])
self.norm = norm_layer(embed_dim)
self.head = nn.Linear(embed_dim, num_classes) if num_classes > 0 else nn.Identity()
if use_learnable_pos_emb:
trunc_normal_(self.pos_embed, std=.02)
self.apply(self._init_weights)
def _init_weights(self, m):
if isinstance(m, nn.Linear):
nn.init.xavier_uniform_(m.weight)
if isinstance(m, nn.Linear) and m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.LayerNorm):
nn.init.constant_(m.bias, 0)
nn.init.constant_(m.weight, 1.0)
def get_num_layers(self):
return len(self.blocks)
@torch.jit.ignore
def no_weight_decay(self):
return {'pos_embed', 'cls_token'}
def get_classifier(self):
return self.head
def reset_classifier(self, num_classes, global_pool=''):
self.num_classes = num_classes
self.head = nn.Linear(self.embed_dim, num_classes) if num_classes > 0 else nn.Identity()
def forward_features(self, x, mask):
_, _, T, _, _ = x.shape
x = self.patch_embed(x)
x = x + self.pos_embed.type_as(x).to(x.device).clone().detach()
B, _, C = x.shape
x_vis = x[~mask].reshape(B, -1, C) # ~mask means visible
if self.use_checkpoint:
for blk in self.blocks:
x_vis = checkpoint.checkpoint(blk, x_vis)
else:
for blk in self.blocks:
x_vis = blk(x_vis)
x_vis = self.norm(x_vis)
return x_vis
def forward(self, x, mask):
x = self.forward_features(x, mask)
x = self.head(x)
return x
class PretrainVisionTransformerDecoder(nn.Module):
""" Vision Transformer with support for patch or hybrid CNN input stage
"""
def __init__(self, patch_size=16, num_classes=768, embed_dim=768, depth=12, num_heads=12, mlp_ratio=4.,
qkv_bias=False, qk_scale=None, drop_rate=0., attn_drop_rate=0., drop_path_rate=0.,
norm_layer=nn.LayerNorm, init_values=None, num_patches=196, tubelet_size=2, use_checkpoint=False
):
super().__init__()
self.num_classes = num_classes
assert num_classes == 3 * tubelet_size * patch_size ** 2
self.num_features = self.embed_dim = embed_dim # num_features for consistency with other models
self.patch_size = patch_size
self.use_checkpoint = use_checkpoint
dpr = [x.item() for x in torch.linspace(0, drop_path_rate, depth)] # stochastic depth decay rule
self.blocks = nn.ModuleList([
Block(
dim=embed_dim, num_heads=num_heads, mlp_ratio=mlp_ratio, qkv_bias=qkv_bias, qk_scale=qk_scale,
drop=drop_rate, attn_drop=attn_drop_rate, drop_path=dpr[i], norm_layer=norm_layer,
init_values=init_values)
for i in range(depth)])
self.norm = norm_layer(embed_dim)
self.head = nn.Linear(embed_dim, num_classes) if num_classes > 0 else nn.Identity()
self.apply(self._init_weights)
def _init_weights(self, m):
if isinstance(m, nn.Linear):
nn.init.xavier_uniform_(m.weight)
if isinstance(m, nn.Linear) and m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.LayerNorm):
nn.init.constant_(m.bias, 0)
nn.init.constant_(m.weight, 1.0)
def get_num_layers(self):
return len(self.blocks)
@torch.jit.ignore
def no_weight_decay(self):
return {'pos_embed', 'cls_token'}
def get_classifier(self):
return self.head
def reset_classifier(self, num_classes, global_pool=''):
self.num_classes = num_classes
self.head = nn.Linear(self.embed_dim, num_classes) if num_classes > 0 else nn.Identity()
def forward(self, x, return_token_num):
if self.use_checkpoint:
for blk in self.blocks:
x = checkpoint.checkpoint(blk, x)
else:
for blk in self.blocks:
x = blk(x)
if return_token_num > 0:
x = self.head(self.norm(x[:, -return_token_num:])) # only return the mask tokens predict pixels
else:
x = self.head(self.norm(x))
return x
class PretrainVisionTransformer(nn.Module):
""" Vision Transformer with support for patch or hybrid CNN input stage
"""
def __init__(self,
img_size=224,
patch_size=16,
encoder_in_chans=3,
encoder_num_classes=0,
encoder_embed_dim=768,
encoder_depth=12,
encoder_num_heads=12,
decoder_num_classes=1536, # decoder_num_classes=768,
decoder_embed_dim=512,
decoder_depth=8,
decoder_num_heads=8,
mlp_ratio=4.,
qkv_bias=False,
qk_scale=None,
drop_rate=0.,
attn_drop_rate=0.,
drop_path_rate=0.,
norm_layer=nn.LayerNorm,
init_values=0.,
use_learnable_pos_emb=False,
use_checkpoint=False,
tubelet_size=2,
num_classes=0, # avoid the error from create_fn in timm
in_chans=0, # avoid the error from create_fn in timm
):
super().__init__()
self.encoder = PretrainVisionTransformerEncoder(
img_size=img_size,
patch_size=patch_size,
in_chans=encoder_in_chans,
num_classes=encoder_num_classes,
embed_dim=encoder_embed_dim,
depth=encoder_depth,
num_heads=encoder_num_heads,
mlp_ratio=mlp_ratio,
qkv_bias=qkv_bias,
qk_scale=qk_scale,
drop_rate=drop_rate,
attn_drop_rate=attn_drop_rate,
drop_path_rate=drop_path_rate,
norm_layer=norm_layer,
init_values=init_values,
tubelet_size=tubelet_size,
use_checkpoint=use_checkpoint,
use_learnable_pos_emb=use_learnable_pos_emb)
self.decoder = PretrainVisionTransformerDecoder(
patch_size=patch_size,
num_patches=self.encoder.patch_embed.num_patches,
num_classes=decoder_num_classes,
embed_dim=decoder_embed_dim,
depth=decoder_depth,
num_heads=decoder_num_heads,
mlp_ratio=mlp_ratio,
qkv_bias=qkv_bias,
qk_scale=qk_scale,
drop_rate=drop_rate,
attn_drop_rate=attn_drop_rate,
drop_path_rate=drop_path_rate,
norm_layer=norm_layer,
init_values=init_values,
tubelet_size=tubelet_size,
use_checkpoint=use_checkpoint)
self.encoder_to_decoder = nn.Linear(encoder_embed_dim, decoder_embed_dim, bias=False)
self.mask_token = nn.Parameter(torch.zeros(1, 1, decoder_embed_dim))
self.pos_embed = get_sinusoid_encoding_table(self.encoder.patch_embed.num_patches, decoder_embed_dim)
trunc_normal_(self.mask_token, std=.02)
def _init_weights(self, m):
if isinstance(m, nn.Linear):
nn.init.xavier_uniform_(m.weight)
if isinstance(m, nn.Linear) and m.bias is not None:
nn.init.constant_(m.bias, 0)
elif isinstance(m, nn.LayerNorm):
nn.init.constant_(m.bias, 0)
nn.init.constant_(m.weight, 1.0)
def get_num_layers(self):
return len(self.blocks)
@torch.jit.ignore
def no_weight_decay(self):
return {'pos_embed', 'cls_token', 'mask_token'}
def forward(self, x, mask):
_, _, T, _, _ = x.shape
x_vis = self.encoder(x, mask) # [B, N_vis, C_e]
x_vis = self.encoder_to_decoder(x_vis) # [B, N_vis, C_d]
B, N, C = x_vis.shape
# we don't unshuffle the correct visible token order,
# but shuffle the pos embedding accorddingly.
expand_pos_embed = self.pos_embed.expand(B, -1, -1).type_as(x).to(x.device).clone().detach()
pos_emd_vis = expand_pos_embed[~mask].reshape(B, -1, C)
pos_emd_mask = expand_pos_embed[mask].reshape(B, -1, C)
x_full = torch.cat([x_vis + pos_emd_vis, self.mask_token + pos_emd_mask], dim=1) # [B, N, C_d]
x = self.decoder(x_full, pos_emd_mask.shape[1]) # [B, N_mask, 3 * 16 * 16]
return x
@register_model
def pretrain_videomae_small_patch16_224(pretrained=False, **kwargs):
model = PretrainVisionTransformer(
img_size=224,
patch_size=16,
encoder_embed_dim=384,
encoder_depth=12,
encoder_num_heads=6,
encoder_num_classes=0,
decoder_num_classes=1536,
decoder_embed_dim=192,
decoder_num_heads=3,
mlp_ratio=4,
qkv_bias=True,
norm_layer=partial(nn.LayerNorm, eps=1e-6),
**kwargs)
model.default_cfg = _cfg()
if pretrained:
checkpoint = torch.load(
kwargs["init_ckpt"], map_location="cpu"
)
model.load_state_dict(checkpoint["model"])
return model
@register_model
def pretrain_videomae_base_patch16_224(pretrained=False, **kwargs):
model = PretrainVisionTransformer(
img_size=224,
patch_size=16,
encoder_embed_dim=768,
encoder_depth=12,
encoder_num_heads=12,
encoder_num_classes=0,
decoder_num_classes=1536,
decoder_embed_dim=384,
decoder_num_heads=6,
mlp_ratio=4,
qkv_bias=True,
norm_layer=partial(nn.LayerNorm, eps=1e-6),
**kwargs)
model.default_cfg = _cfg()
if pretrained:
checkpoint = torch.load(
kwargs["init_ckpt"], map_location="cpu"
)
model.load_state_dict(checkpoint["model"])
return model
@register_model
def pretrain_videomae_large_patch16_224(pretrained=False, **kwargs):
model = PretrainVisionTransformer(
img_size=224,
patch_size=16,
encoder_embed_dim=1024,
encoder_depth=24,
encoder_num_heads=16,
encoder_num_classes=0,
decoder_num_classes=1536,
decoder_embed_dim=512,
decoder_num_heads=8,
mlp_ratio=4,
qkv_bias=True,
norm_layer=partial(nn.LayerNorm, eps=1e-6),
**kwargs)
model.default_cfg = _cfg()
if pretrained:
checkpoint = torch.load(
kwargs["init_ckpt"], map_location="cpu"
)
model.load_state_dict(checkpoint["model"])
return model
@register_model
def pretrain_videomae_huge_patch16_224(pretrained=False, **kwargs):
model = PretrainVisionTransformer(
img_size=224,
patch_size=16,
encoder_embed_dim=1280,
encoder_depth=32,
encoder_num_heads=16,
encoder_num_classes=0,
decoder_num_classes=1536,
decoder_embed_dim=640,
decoder_num_heads=8,
mlp_ratio=4,
qkv_bias=True,
norm_layer=partial(nn.LayerNorm, eps=1e-6),
**kwargs)
model.default_cfg = _cfg()
if pretrained:
checkpoint = torch.load(
kwargs["init_ckpt"], map_location="cpu"
)
model.load_state_dict(checkpoint["model"])
return model