/usr/local/lib/python3.6/site-packages/transformers/models/swin
Edit: /usr/local/lib/python3.6/site-packages/transformers/models/swin/modeling_swin.py (51021B)
# coding=utf-8
# Copyright 2022 Microsoft Research and The HuggingFace Inc. team. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
""" PyTorch Swin Transformer model."""
import collections.abc
import math
from dataclasses import dataclass
from typing import Optional, Tuple
import torch
import torch.utils.checkpoint
from torch import nn
from torch.nn import BCEWithLogitsLoss, CrossEntropyLoss, MSELoss
from ...activations import ACT2FN
from ...modeling_utils import PreTrainedModel, find_pruneable_heads_and_indices, prune_linear_layer
from ...utils import (
ModelOutput,
add_code_sample_docstrings,
add_start_docstrings,
add_start_docstrings_to_model_forward,
logging,
replace_return_docstrings,
)
from .configuration_swin import SwinConfig
logger = logging.get_logger(__name__)
# General docstring
_CONFIG_FOR_DOC = "SwinConfig"
_FEAT_EXTRACTOR_FOR_DOC = "AutoFeatureExtractor"
# Base docstring
_CHECKPOINT_FOR_DOC = "microsoft/swin-tiny-patch4-window7-224"
_EXPECTED_OUTPUT_SHAPE = [1, 49, 768]
# Image classification docstring
_IMAGE_CLASS_CHECKPOINT = "microsoft/swin-tiny-patch4-window7-224"
_IMAGE_CLASS_EXPECTED_OUTPUT = "tabby, tabby cat"
SWIN_PRETRAINED_MODEL_ARCHIVE_LIST = [
"microsoft/swin-tiny-patch4-window7-224",
# See all Swin models at https://huggingface.co/models?filter=swin
]
# to_2tuple, drop_path, SwinPatchEmbeddings, SwinPatchMerging and SwinDropPath are from the timm library.
@dataclass
class SwinEncoderOutput(ModelOutput):
"""
Swin encoder's outputs, with potential hidden states and attentions.
Args:
last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`):
Sequence of hidden-states at the output of the last layer of the model.
hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`):
Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each stage) of
shape `(batch_size, sequence_length, hidden_size)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs.
attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`):
Tuple of `torch.FloatTensor` (one for each stage) of shape `(batch_size, num_heads, sequence_length,
sequence_length)`.
Attentions weights after the attention softmax, used to compute the weighted average in the self-attention
heads.
reshaped_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`):
Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each stage) of
shape `(batch_size, hidden_size, height, width)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs reshaped to
include the spatial dimensions.
"""
last_hidden_state: torch.FloatTensor = None
hidden_states: Optional[Tuple[torch.FloatTensor]] = None
attentions: Optional[Tuple[torch.FloatTensor]] = None
reshaped_hidden_states: Optional[Tuple[torch.FloatTensor]] = None
@dataclass
class SwinModelOutput(ModelOutput):
"""
Swin model's outputs that also contains a pooling of the last hidden states.
Args:
last_hidden_state (`torch.FloatTensor` of shape `(batch_size, sequence_length, hidden_size)`):
Sequence of hidden-states at the output of the last layer of the model.
pooler_output (`torch.FloatTensor` of shape `(batch_size, hidden_size)`):
Average pooling of the last layer hidden-state.
hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`):
Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each stage) of
shape `(batch_size, sequence_length, hidden_size)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs.
attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`):
Tuple of `torch.FloatTensor` (one for each stage) of shape `(batch_size, num_heads, sequence_length,
sequence_length)`.
Attentions weights after the attention softmax, used to compute the weighted average in the self-attention
heads.
reshaped_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`):
Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each stage) of
shape `(batch_size, hidden_size, height, width)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs reshaped to
include the spatial dimensions.
"""
last_hidden_state: torch.FloatTensor = None
pooler_output: torch.FloatTensor = None
hidden_states: Optional[Tuple[torch.FloatTensor]] = None
attentions: Optional[Tuple[torch.FloatTensor]] = None
reshaped_hidden_states: Optional[Tuple[torch.FloatTensor]] = None
@dataclass
class SwinMaskedImageModelingOutput(ModelOutput):
"""
Swin masked image model outputs.
Args:
loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `bool_masked_pos` is provided):
Masked image modeling (MLM) loss.
logits (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)`):
Reconstructed pixel values.
hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`):
Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each stage) of
shape `(batch_size, sequence_length, hidden_size)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs.
attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`):
Tuple of `torch.FloatTensor` (one for each stage) of shape `(batch_size, num_heads, sequence_length,
sequence_length)`.
Attentions weights after the attention softmax, used to compute the weighted average in the self-attention
heads.
reshaped_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`):
Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each stage) of
shape `(batch_size, hidden_size, height, width)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs reshaped to
include the spatial dimensions.
"""
loss: Optional[torch.FloatTensor] = None
logits: torch.FloatTensor = None
hidden_states: Optional[Tuple[torch.FloatTensor]] = None
attentions: Optional[Tuple[torch.FloatTensor]] = None
reshaped_hidden_states: Optional[Tuple[torch.FloatTensor]] = None
@dataclass
class SwinImageClassifierOutput(ModelOutput):
"""
Swin outputs for image classification.
Args:
loss (`torch.FloatTensor` of shape `(1,)`, *optional*, returned when `labels` is provided):
Classification (or regression if config.num_labels==1) loss.
logits (`torch.FloatTensor` of shape `(batch_size, config.num_labels)`):
Classification (or regression if config.num_labels==1) scores (before SoftMax).
hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`):
Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each stage) of
shape `(batch_size, sequence_length, hidden_size)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs.
attentions (`tuple(torch.FloatTensor)`, *optional*, returned when `output_attentions=True` is passed or when `config.output_attentions=True`):
Tuple of `torch.FloatTensor` (one for each stage) of shape `(batch_size, num_heads, sequence_length,
sequence_length)`.
Attentions weights after the attention softmax, used to compute the weighted average in the self-attention
heads.
reshaped_hidden_states (`tuple(torch.FloatTensor)`, *optional*, returned when `output_hidden_states=True` is passed or when `config.output_hidden_states=True`):
Tuple of `torch.FloatTensor` (one for the output of the embeddings + one for the output of each stage) of
shape `(batch_size, hidden_size, height, width)`.
Hidden-states of the model at the output of each layer plus the initial embedding outputs reshaped to
include the spatial dimensions.
"""
loss: Optional[torch.FloatTensor] = None
logits: torch.FloatTensor = None
hidden_states: Optional[Tuple[torch.FloatTensor]] = None
attentions: Optional[Tuple[torch.FloatTensor]] = None
reshaped_hidden_states: Optional[Tuple[torch.FloatTensor]] = None
# Copied from transformers.models.vit.modeling_vit.to_2tuple
def to_2tuple(x):
if isinstance(x, collections.abc.Iterable):
return x
return (x, x)
def window_partition(input_feature, window_size):
"""
Partitions the given input into windows.
"""
batch_size, height, width, num_channels = input_feature.shape
input_feature = input_feature.view(
batch_size, height // window_size, window_size, width // window_size, window_size, num_channels
)
windows = input_feature.permute(0, 1, 3, 2, 4, 5).contiguous().view(-1, window_size, window_size, num_channels)
return windows
def window_reverse(windows, window_size, height, width):
"""
Merges windows to produce higher resolution features.
"""
batch_size = int(windows.shape[0] / (height * width / window_size / window_size))
windows = windows.view(batch_size, height // window_size, width // window_size, window_size, window_size, -1)
windows = windows.permute(0, 1, 3, 2, 4, 5).contiguous().view(batch_size, height, width, -1)
return windows
def drop_path(input, drop_prob=0.0, training=False, scale_by_keep=True):
"""
Drop paths (Stochastic Depth) per sample (when applied in main path of residual blocks).
"""
if drop_prob == 0.0 or not training:
return input
keep_prob = 1 - drop_prob
shape = (input.shape[0],) + (1,) * (input.ndim - 1) # work with diff dim tensors, not just 2D ConvNets
random_tensor = input.new_empty(shape).bernoulli_(keep_prob)
if keep_prob > 0.0 and scale_by_keep:
random_tensor.div_(keep_prob)
return input * random_tensor
class SwinEmbeddings(nn.Module):
"""
Construct the patch and position embeddings. Optionally, also the mask token.
"""
def __init__(self, config, use_mask_token=False):
super().__init__()
self.patch_embeddings = SwinPatchEmbeddings(
image_size=config.image_size,
patch_size=config.patch_size,
num_channels=config.num_channels,
embed_dim=config.embed_dim,
)
num_patches = self.patch_embeddings.num_patches
self.patch_grid = self.patch_embeddings.grid_size
self.mask_token = nn.Parameter(torch.zeros(1, 1, config.embed_dim)) if use_mask_token else None
if config.use_absolute_embeddings:
self.position_embeddings = nn.Parameter(torch.zeros(1, num_patches + 1, config.embed_dim))
else:
self.position_embeddings = None
self.norm = nn.LayerNorm(config.embed_dim)
self.dropout = nn.Dropout(config.hidden_dropout_prob)
def forward(self, pixel_values, bool_masked_pos=None):
embeddings, output_dimensions = self.patch_embeddings(pixel_values)
embeddings = self.norm(embeddings)
batch_size, seq_len, _ = embeddings.size()
if bool_masked_pos is not None:
mask_tokens = self.mask_token.expand(batch_size, seq_len, -1)
# replace the masked visual tokens by mask_tokens
mask = bool_masked_pos.unsqueeze(-1).type_as(mask_tokens)
embeddings = embeddings * (1.0 - mask) + mask_tokens * mask
if self.position_embeddings is not None:
embeddings = embeddings + self.position_embeddings
embeddings = self.dropout(embeddings)
return embeddings, output_dimensions
class SwinPatchEmbeddings(nn.Module):
"""
Image to Patch Embedding.
"""
def __init__(self, image_size=224, patch_size=16, num_channels=3, embed_dim=768):
super().__init__()
image_size = to_2tuple(image_size)
patch_size = to_2tuple(patch_size)
num_patches = (image_size[1] // patch_size[1]) * (image_size[0] // patch_size[0])
self.image_size = image_size
self.patch_size = patch_size
self.num_patches = num_patches
self.grid_size = (image_size[0] // patch_size[0], image_size[1] // patch_size[1])
self.projection = nn.Conv2d(num_channels, embed_dim, kernel_size=patch_size, stride=patch_size)
def maybe_pad(self, pixel_values, height, width):
if width % self.patch_size[1] != 0:
pad_values = (0, self.patch_size[1] - width % self.patch_size[1])
pixel_values = nn.functional.pad(pixel_values, pad_values)
if height % self.patch_size[0] != 0:
pad_values = (0, 0, 0, self.patch_size[0] - height % self.patch_size[0])
pixel_values = nn.functional.pad(pixel_values, pad_values)
return pixel_values
def forward(self, pixel_values):
_, _, height, width = pixel_values.shape
# pad the input to be divisible by self.patch_size, if needed
pixel_values = self.maybe_pad(pixel_values, height, width)
embeddings = self.projection(pixel_values)
_, _, height, width = embeddings.shape
output_dimensions = (height, width)
embeddings = embeddings.flatten(2).transpose(1, 2)
return embeddings, output_dimensions
class SwinPatchMerging(nn.Module):
"""
Patch Merging Layer.
Args:
input_resolution (`Tuple[int]`):
Resolution of input feature.
dim (`int`):
Number of input channels.
norm_layer (`nn.Module`, *optional*, defaults to `nn.LayerNorm`):
Normalization layer class.
"""
def __init__(self, input_resolution, dim, norm_layer=nn.LayerNorm):
super().__init__()
self.input_resolution = input_resolution
self.dim = dim
self.reduction = nn.Linear(4 * dim, 2 * dim, bias=False)
self.norm = norm_layer(4 * dim)
def maybe_pad(self, input_feature, height, width):
should_pad = (height % 2 == 1) or (width % 2 == 1)
if should_pad:
pad_values = (0, 0, 0, width % 2, 0, height % 2)
input_feature = nn.functional.pad(input_feature, pad_values)
return input_feature
def forward(self, input_feature, input_dimensions):
height, width = input_dimensions
# `dim` is height * width
batch_size, dim, num_channels = input_feature.shape
input_feature = input_feature.view(batch_size, height, width, num_channels)
# pad input to be disible by width and height, if needed
input_feature = self.maybe_pad(input_feature, height, width)
# [batch_size, height/2, width/2, num_channels]
input_feature_0 = input_feature[:, 0::2, 0::2, :]
# [batch_size, height/2, width/2, num_channels]
input_feature_1 = input_feature[:, 1::2, 0::2, :]
# [batch_size, height/2, width/2, num_channels]
input_feature_2 = input_feature[:, 0::2, 1::2, :]
# [batch_size, height/2, width/2, num_channels]
input_feature_3 = input_feature[:, 1::2, 1::2, :]
# batch_size height/2 width/2 4*num_channels
input_feature = torch.cat([input_feature_0, input_feature_1, input_feature_2, input_feature_3], -1)
input_feature = input_feature.view(batch_size, -1, 4 * num_channels) # batch_size height/2*width/2 4*C
input_feature = self.norm(input_feature)
input_feature = self.reduction(input_feature)
return input_feature
class SwinDropPath(nn.Module):
"""Drop paths (Stochastic Depth) per sample (when applied in main path of residual blocks)."""
def __init__(self, drop_prob=None, scale_by_keep=True):
super(SwinDropPath, self).__init__()
self.drop_prob = drop_prob
self.scale_by_keep = scale_by_keep
def forward(self, input):
return drop_path(input, self.drop_prob, self.training, self.scale_by_keep)
class SwinSelfAttention(nn.Module):
def __init__(self, config, dim, num_heads):
super().__init__()
if dim % num_heads != 0:
raise ValueError(
f"The hidden size ({dim}) is not a multiple of the number of attention " f"heads ({num_heads})"
)
self.num_attention_heads = num_heads
self.attention_head_size = int(dim / num_heads)
self.all_head_size = self.num_attention_heads * self.attention_head_size
self.window_size = to_2tuple(config.window_size)
self.relative_position_bias_table = nn.Parameter(
torch.zeros((2 * self.window_size[0] - 1) * (2 * self.window_size[1] - 1), num_heads)
)
# get pair-wise relative position index for each token inside the window
coords_h = torch.arange(self.window_size[0])
coords_w = torch.arange(self.window_size[1])
coords = torch.stack(torch.meshgrid([coords_h, coords_w]))
coords_flatten = torch.flatten(coords, 1)
relative_coords = coords_flatten[:, :, None] - coords_flatten[:, None, :]
relative_coords = relative_coords.permute(1, 2, 0).contiguous()
relative_coords[:, :, 0] += self.window_size[0] - 1
relative_coords[:, :, 1] += self.window_size[1] - 1
relative_coords[:, :, 0] *= 2 * self.window_size[1] - 1
relative_position_index = relative_coords.sum(-1)
self.register_buffer("relative_position_index", relative_position_index)
self.query = nn.Linear(self.all_head_size, self.all_head_size, bias=config.qkv_bias)
self.key = nn.Linear(self.all_head_size, self.all_head_size, bias=config.qkv_bias)
self.value = nn.Linear(self.all_head_size, self.all_head_size, bias=config.qkv_bias)
self.dropout = nn.Dropout(config.attention_probs_dropout_prob)
def transpose_for_scores(self, x):
new_x_shape = x.size()[:-1] + (self.num_attention_heads, self.attention_head_size)
x = x.view(*new_x_shape)
return x.permute(0, 2, 1, 3)
def forward(
self,
hidden_states,
attention_mask=None,
head_mask=None,
output_attentions=False,
):
batch_size, dim, num_channels = hidden_states.shape
mixed_query_layer = self.query(hidden_states)
key_layer = self.transpose_for_scores(self.key(hidden_states))
value_layer = self.transpose_for_scores(self.value(hidden_states))
query_layer = self.transpose_for_scores(mixed_query_layer)
# Take the dot product between "query" and "key" to get the raw attention scores.
attention_scores = torch.matmul(query_layer, key_layer.transpose(-1, -2))
attention_scores = attention_scores / math.sqrt(self.attention_head_size)
relative_position_bias = self.relative_position_bias_table[self.relative_position_index.view(-1)]
relative_position_bias = relative_position_bias.view(
self.window_size[0] * self.window_size[1], self.window_size[0] * self.window_size[1], -1
)
relative_position_bias = relative_position_bias.permute(2, 0, 1).contiguous()
attention_scores = attention_scores + relative_position_bias.unsqueeze(0)
if attention_mask is not None:
# Apply the attention mask is (precomputed for all layers in SwinModel forward() function)
mask_shape = attention_mask.shape[0]
attention_scores = attention_scores.view(
batch_size // mask_shape, mask_shape, self.num_attention_heads, dim, dim
)
attention_scores = attention_scores + attention_mask.unsqueeze(1).unsqueeze(0)
attention_scores = attention_scores.view(-1, self.num_attention_heads, dim, dim)
# Normalize the attention scores to probabilities.
attention_probs = nn.functional.softmax(attention_scores, dim=-1)
# This is actually dropping out entire tokens to attend to, which might
# seem a bit unusual, but is taken from the original Transformer paper.
attention_probs = self.dropout(attention_probs)
# Mask heads if we want to
if head_mask is not None:
attention_probs = attention_probs * head_mask
context_layer = torch.matmul(attention_probs, value_layer)
context_layer = context_layer.permute(0, 2, 1, 3).contiguous()
new_context_layer_shape = context_layer.size()[:-2] + (self.all_head_size,)
context_layer = context_layer.view(*new_context_layer_shape)
outputs = (context_layer, attention_probs) if output_attentions else (context_layer,)
return outputs
class SwinSelfOutput(nn.Module):
def __init__(self, config, dim):
super().__init__()
self.dense = nn.Linear(dim, dim)
self.dropout = nn.Dropout(config.attention_probs_dropout_prob)
def forward(self, hidden_states, input_tensor):
hidden_states = self.dense(hidden_states)
hidden_states = self.dropout(hidden_states)
return hidden_states
class SwinAttention(nn.Module):
def __init__(self, config, dim, num_heads):
super().__init__()
self.self = SwinSelfAttention(config, dim, num_heads)
self.output = SwinSelfOutput(config, dim)
self.pruned_heads = set()
def prune_heads(self, heads):
if len(heads) == 0:
return
heads, index = find_pruneable_heads_and_indices(
heads, self.self.num_attention_heads, self.self.attention_head_size, self.pruned_heads
)
# Prune linear layers
self.self.query = prune_linear_layer(self.self.query, index)
self.self.key = prune_linear_layer(self.self.key, index)
self.self.value = prune_linear_layer(self.self.value, index)
self.output.dense = prune_linear_layer(self.output.dense, index, dim=1)
# Update hyper params and store pruned heads
self.self.num_attention_heads = self.self.num_attention_heads - len(heads)
self.self.all_head_size = self.self.attention_head_size * self.self.num_attention_heads
self.pruned_heads = self.pruned_heads.union(heads)
def forward(self, hidden_states, attention_mask=None, head_mask=None, output_attentions=False):
self_outputs = self.self(hidden_states, attention_mask, head_mask, output_attentions)
attention_output = self.output(self_outputs[0], hidden_states)
outputs = (attention_output,) + self_outputs[1:] # add attentions if we output them
return outputs
class SwinIntermediate(nn.Module):
def __init__(self, config, dim):
super().__init__()
self.dense = nn.Linear(dim, int(config.mlp_ratio * dim))
if isinstance(config.hidden_act, str):
self.intermediate_act_fn = ACT2FN[config.hidden_act]
else:
self.intermediate_act_fn = config.hidden_act
def forward(self, hidden_states):
hidden_states = self.dense(hidden_states)
hidden_states = self.intermediate_act_fn(hidden_states)
return hidden_states
class SwinOutput(nn.Module):
def __init__(self, config, dim):
super().__init__()
self.dense = nn.Linear(int(config.mlp_ratio * dim), dim)
self.dropout = nn.Dropout(config.hidden_dropout_prob)
def forward(self, hidden_states):
hidden_states = self.dense(hidden_states)
hidden_states = self.dropout(hidden_states)
return hidden_states
class SwinLayer(nn.Module):
def __init__(self, config, dim, input_resolution, num_heads, shift_size=0):
super().__init__()
self.chunk_size_feed_forward = config.chunk_size_feed_forward
self.shift_size = shift_size
self.window_size = config.window_size
self.input_resolution = input_resolution
self.set_shift_and_window_size(input_resolution)
self.layernorm_before = nn.LayerNorm(dim, eps=config.layer_norm_eps)
self.attention = SwinAttention(config, dim, num_heads)
self.drop_path = SwinDropPath(config.drop_path_rate) if config.drop_path_rate > 0.0 else nn.Identity()
self.layernorm_after = nn.LayerNorm(dim, eps=config.layer_norm_eps)
self.intermediate = SwinIntermediate(config, dim)
self.output = SwinOutput(config, dim)
def set_shift_and_window_size(self, input_resolution):
if min(input_resolution) <= self.window_size:
# if window size is larger than input resolution, we don't partition windows
self.shift_size = 0
self.window_size = min(input_resolution)
def get_attn_mask(self, height, width):
if self.shift_size > 0:
# calculate attention mask for SW-MSA
img_mask = torch.zeros((1, height, width, 1))
height_slices = (
slice(0, -self.window_size),
slice(-self.window_size, -self.shift_size),
slice(-self.shift_size, None),
)
width_slices = (
slice(0, -self.window_size),
slice(-self.window_size, -self.shift_size),
slice(-self.shift_size, None),
)
count = 0
for height_slice in height_slices:
for width_slice in width_slices:
img_mask[:, height_slice, width_slice, :] = count
count += 1
mask_windows = window_partition(img_mask, self.window_size)
mask_windows = mask_windows.view(-1, self.window_size * self.window_size)
attn_mask = mask_windows.unsqueeze(1) - mask_windows.unsqueeze(2)
attn_mask = attn_mask.masked_fill(attn_mask != 0, float(-100.0)).masked_fill(attn_mask == 0, float(0.0))
else:
attn_mask = None
return attn_mask
def maybe_pad(self, hidden_states, height, width):
pad_right = (self.window_size - width % self.window_size) % self.window_size
pad_bottom = (self.window_size - height % self.window_size) % self.window_size
pad_values = (0, 0, 0, pad_right, 0, pad_bottom)
hidden_states = nn.functional.pad(hidden_states, pad_values)
return hidden_states, pad_values
def forward(self, hidden_states, input_dimensions, head_mask=None, output_attentions=False):
self.set_shift_and_window_size(input_dimensions)
height, width = input_dimensions
batch_size, _, channels = hidden_states.size()
shortcut = hidden_states
hidden_states = self.layernorm_before(hidden_states)
hidden_states = hidden_states.view(batch_size, height, width, channels)
# pad hidden_states to multiples of window size
hidden_states, pad_values = self.maybe_pad(hidden_states, height, width)
_, height_pad, width_pad, _ = hidden_states.shape
# cyclic shift
if self.shift_size > 0:
shifted_hidden_states = torch.roll(hidden_states, shifts=(-self.shift_size, -self.shift_size), dims=(1, 2))
else:
shifted_hidden_states = hidden_states
# partition windows
hidden_states_windows = window_partition(shifted_hidden_states, self.window_size)
hidden_states_windows = hidden_states_windows.view(-1, self.window_size * self.window_size, channels)
attn_mask = self.get_attn_mask(height_pad, width_pad)
if attn_mask is not None:
attn_mask = attn_mask.to(hidden_states_windows.device)
attention_outputs = self.attention(
hidden_states_windows, attn_mask, head_mask, output_attentions=output_attentions
)
attention_output = attention_outputs[0]
attention_windows = attention_output.view(-1, self.window_size, self.window_size, channels)
shifted_windows = window_reverse(attention_windows, self.window_size, height_pad, width_pad)
# reverse cyclic shift
if self.shift_size > 0:
attention_windows = torch.roll(shifted_windows, shifts=(self.shift_size, self.shift_size), dims=(1, 2))
else:
attention_windows = shifted_windows
was_padded = pad_values[3] > 0 or pad_values[5] > 0
if was_padded:
attention_windows = attention_windows[:, :height, :width, :].contiguous()
attention_windows = attention_windows.view(batch_size, height * width, channels)
hidden_states = shortcut + self.drop_path(attention_windows)
layer_output = self.layernorm_after(hidden_states)
layer_output = self.intermediate(layer_output)
layer_output = hidden_states + self.output(layer_output)
layer_outputs = (layer_output, attention_outputs[1]) if output_attentions else (layer_output,)
return layer_outputs
class SwinStage(nn.Module):
def __init__(self, config, dim, input_resolution, depth, num_heads, drop_path, downsample):
super().__init__()
self.config = config
self.dim = dim
self.blocks = nn.ModuleList(
[
SwinLayer(
config=config,
dim=dim,
input_resolution=input_resolution,
num_heads=num_heads,
shift_size=0 if (i % 2 == 0) else config.window_size // 2,
)
for i in range(depth)
]
)
# patch merging layer
if downsample is not None:
self.downsample = downsample(input_resolution, dim=dim, norm_layer=nn.LayerNorm)
else:
self.downsample = None
self.pointing = False
def forward(self, hidden_states, input_dimensions, head_mask=None, output_attentions=False):
height, width = input_dimensions
for i, layer_module in enumerate(self.blocks):
layer_head_mask = head_mask[i] if head_mask is not None else None
layer_outputs = layer_module(hidden_states, input_dimensions, layer_head_mask, output_attentions)
hidden_states = layer_outputs[0]
if self.downsample is not None:
height_downsampled, width_downsampled = (height + 1) // 2, (width + 1) // 2
output_dimensions = (height, width, height_downsampled, width_downsampled)
hidden_states = self.downsample(layer_outputs[0], input_dimensions)
else:
output_dimensions = (height, width, height, width)
stage_outputs = (hidden_states, output_dimensions)
if output_attentions:
stage_outputs += layer_outputs[1:]
return stage_outputs
class SwinEncoder(nn.Module):
def __init__(self, config, grid_size):
super().__init__()
self.num_layers = len(config.depths)
self.config = config
dpr = [x.item() for x in torch.linspace(0, config.drop_path_rate, sum(config.depths))]
self.layers = nn.ModuleList(
[
SwinStage(
config=config,
dim=int(config.embed_dim * 2**i_layer),
input_resolution=(grid_size[0] // (2**i_layer), grid_size[1] // (2**i_layer)),
depth=config.depths[i_layer],
num_heads=config.num_heads[i_layer],
drop_path=dpr[sum(config.depths[:i_layer]) : sum(config.depths[: i_layer + 1])],
downsample=SwinPatchMerging if (i_layer < self.num_layers - 1) else None,
)
for i_layer in range(self.num_layers)
]
)
self.gradient_checkpointing = False
def forward(
self,
hidden_states,
input_dimensions,
head_mask=None,
output_attentions=False,
output_hidden_states=False,
return_dict=True,
):
all_input_dimensions = ()
all_hidden_states = () if output_hidden_states else None
all_reshaped_hidden_states = () if output_hidden_states else None
all_self_attentions = () if output_attentions else None
if output_hidden_states:
batch_size, _, hidden_size = hidden_states.shape
# rearrange b (h w) c -> b c h w
reshaped_hidden_state = hidden_states.view(batch_size, *input_dimensions, hidden_size)
reshaped_hidden_state = reshaped_hidden_state.permute(0, 3, 1, 2)
all_hidden_states += (hidden_states,)
all_reshaped_hidden_states += (reshaped_hidden_state,)
for i, layer_module in enumerate(self.layers):
layer_head_mask = head_mask[i] if head_mask is not None else None
if self.gradient_checkpointing and self.training:
def create_custom_forward(module):
def custom_forward(*inputs):
return module(*inputs, output_attentions)
return custom_forward
layer_outputs = torch.utils.checkpoint.checkpoint(
create_custom_forward(layer_module), hidden_states, input_dimensions, layer_head_mask
)
else:
layer_outputs = layer_module(hidden_states, input_dimensions, layer_head_mask, output_attentions)
hidden_states = layer_outputs[0]
output_dimensions = layer_outputs[1]
input_dimensions = (output_dimensions[-2], output_dimensions[-1])
all_input_dimensions += (input_dimensions,)
if output_hidden_states:
batch_size, _, hidden_size = hidden_states.shape
# rearrange b (h w) c -> b c h w
reshaped_hidden_state = hidden_states.view(batch_size, *input_dimensions, hidden_size)
reshaped_hidden_state = reshaped_hidden_state.permute(0, 3, 1, 2)
all_hidden_states += (hidden_states,)
all_reshaped_hidden_states += (reshaped_hidden_state,)
if output_attentions:
all_self_attentions += layer_outputs[2:]
if not return_dict:
return tuple(v for v in [hidden_states, all_hidden_states, all_self_attentions] if v is not None)
return SwinEncoderOutput(
last_hidden_state=hidden_states,
hidden_states=all_hidden_states,
attentions=all_self_attentions,
reshaped_hidden_states=all_reshaped_hidden_states,
)
class SwinPreTrainedModel(PreTrainedModel):
"""
An abstract class to handle weights initialization and a simple interface for downloading and loading pretrained
models.
"""
config_class = SwinConfig
base_model_prefix = "swin"
main_input_name = "pixel_values"
supports_gradient_checkpointing = True
def _init_weights(self, module):
"""Initialize the weights"""
if isinstance(module, (nn.Linear, nn.Conv2d)):
# Slightly different from the TF version which uses truncated_normal for initialization
# cf https://github.com/pytorch/pytorch/pull/5617
module.weight.data.normal_(mean=0.0, std=self.config.initializer_range)
if module.bias is not None:
module.bias.data.zero_()
elif isinstance(module, nn.LayerNorm):
module.bias.data.zero_()
module.weight.data.fill_(1.0)
def _set_gradient_checkpointing(self, module, value=False):
if isinstance(module, SwinEncoder):
module.gradient_checkpointing = value
SWIN_START_DOCSTRING = r"""
This model is a PyTorch [torch.nn.Module](https://pytorch.org/docs/stable/nn.html#torch.nn.Module) sub-class. Use
it as a regular PyTorch Module and refer to the PyTorch documentation for all matter related to general usage and
behavior.
Parameters:
config ([`SwinConfig`]): Model configuration class with all the parameters of the model.
Initializing with a config file does not load the weights associated with the model, only the
configuration. Check out the [`~PreTrainedModel.from_pretrained`] method to load the model weights.
"""
SWIN_INPUTS_DOCSTRING = r"""
Args:
pixel_values (`torch.FloatTensor` of shape `(batch_size, num_channels, height, width)`):
Pixel values. Pixel values can be obtained using [`AutoFeatureExtractor`]. See
[`AutoFeatureExtractor.__call__`] for details.
head_mask (`torch.FloatTensor` of shape `(num_heads,)` or `(num_layers, num_heads)`, *optional*):
Mask to nullify selected heads of the self-attention modules. Mask values selected in `[0, 1]`:
- 1 indicates the head is **not masked**,
- 0 indicates the head is **masked**.
output_attentions (`bool`, *optional*):
Whether or not to return the attentions tensors of all attention layers. See `attentions` under returned
tensors for more detail.
output_hidden_states (`bool`, *optional*):
Whether or not to return the hidden states of all layers. See `hidden_states` under returned tensors for
more detail.
return_dict (`bool`, *optional*):
Whether or not to return a [`~utils.ModelOutput`] instead of a plain tuple.
"""
@add_start_docstrings(
"The bare Swin Model transformer outputting raw hidden-states without any specific head on top.",
SWIN_START_DOCSTRING,
)
class SwinModel(SwinPreTrainedModel):
def __init__(self, config, add_pooling_layer=True, use_mask_token=False):
super().__init__(config)
self.config = config
self.num_layers = len(config.depths)
self.num_features = int(config.embed_dim * 2 ** (self.num_layers - 1))
self.embeddings = SwinEmbeddings(config, use_mask_token=use_mask_token)
self.encoder = SwinEncoder(config, self.embeddings.patch_grid)
self.layernorm = nn.LayerNorm(self.num_features, eps=config.layer_norm_eps)
self.pooler = nn.AdaptiveAvgPool1d(1) if add_pooling_layer else None
# Initialize weights and apply final processing
self.post_init()
def get_input_embeddings(self):
return self.embeddings.patch_embeddings
def _prune_heads(self, heads_to_prune):
"""
Prunes heads of the model. heads_to_prune: dict of {layer_num: list of heads to prune in this layer} See base
class PreTrainedModel
"""
for layer, heads in heads_to_prune.items():
self.encoder.layer[layer].attention.prune_heads(heads)
@add_start_docstrings_to_model_forward(SWIN_INPUTS_DOCSTRING)
@add_code_sample_docstrings(
processor_class=_FEAT_EXTRACTOR_FOR_DOC,
checkpoint=_CHECKPOINT_FOR_DOC,
output_type=SwinModelOutput,
config_class=_CONFIG_FOR_DOC,
modality="vision",
expected_output=_EXPECTED_OUTPUT_SHAPE,
)
def forward(
self,
pixel_values=None,
bool_masked_pos=None,
head_mask=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
):
output_attentions = output_attentions if output_attentions is not None else self.config.output_attentions
output_hidden_states = (
output_hidden_states if output_hidden_states is not None else self.config.output_hidden_states
)
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
if pixel_values is None:
raise ValueError("You have to specify pixel_values")
# Prepare head mask if needed
# 1.0 in head_mask indicate we keep the head
# attention_probs has shape bsz x n_heads x N x N
# input head_mask has shape [num_heads] or [num_hidden_layers x num_heads]
# and head_mask is converted to shape [num_hidden_layers x batch x num_heads x seq_length x seq_length]
head_mask = self.get_head_mask(head_mask, len(self.config.depths))
embedding_output, input_dimensions = self.embeddings(pixel_values, bool_masked_pos=bool_masked_pos)
encoder_outputs = self.encoder(
embedding_output,
input_dimensions,
head_mask=head_mask,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
)
sequence_output = encoder_outputs[0]
sequence_output = self.layernorm(sequence_output)
pooled_output = None
if self.pooler is not None:
pooled_output = self.pooler(sequence_output.transpose(1, 2))
pooled_output = torch.flatten(pooled_output, 1)
if not return_dict:
output = (sequence_output, pooled_output) + encoder_outputs[1:]
return output
return SwinModelOutput(
last_hidden_state=sequence_output,
pooler_output=pooled_output,
hidden_states=encoder_outputs.hidden_states,
attentions=encoder_outputs.attentions,
reshaped_hidden_states=encoder_outputs.reshaped_hidden_states,
)
@add_start_docstrings(
"Swin Model with a decoder on top for masked image modeling, as proposed in `SimMIM
`__.",
SWIN_START_DOCSTRING,
)
class SwinForMaskedImageModeling(SwinPreTrainedModel):
def __init__(self, config):
super().__init__(config)
self.swin = SwinModel(config, add_pooling_layer=False, use_mask_token=True)
num_features = int(config.embed_dim * 2 ** (config.num_layers - 1))
self.decoder = nn.Sequential(
nn.Conv2d(in_channels=num_features, out_channels=config.encoder_stride**2 * 3, kernel_size=1),
nn.PixelShuffle(config.encoder_stride),
)
# Initialize weights and apply final processing
self.post_init()
@add_start_docstrings_to_model_forward(SWIN_INPUTS_DOCSTRING)
@replace_return_docstrings(output_type=SwinMaskedImageModelingOutput, config_class=_CONFIG_FOR_DOC)
def forward(
self,
pixel_values=None,
bool_masked_pos=None,
head_mask=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
):
r"""
bool_masked_pos (`torch.BoolTensor` of shape `(batch_size, num_patches)`):
Boolean masked positions. Indicates which patches are masked (1) and which aren't (0).
Returns:
Examples:
```python
>>> from transformers import AutoFeatureExtractor, SwinForMaskedImageModeling
>>> import torch
>>> from PIL import Image
>>> import requests
>>> url = "http://images.cocodataset.org/val2017/000000039769.jpg"
>>> image = Image.open(requests.get(url, stream=True).raw)
>>> feature_extractor = AutoFeatureExtractor.from_pretrained("microsoft/swin-tiny-patch4-window7-224")
>>> model = SwinForMaskedImageModeling.from_pretrained("microsoft/swin-tiny-patch4-window7-224")
>>> num_patches = (model.config.image_size // model.config.patch_size) ** 2
>>> pixel_values = feature_extractor(images=image, return_tensors="pt").pixel_values
>>> # create random boolean mask of shape (batch_size, num_patches)
>>> bool_masked_pos = torch.randint(low=0, high=2, size=(1, num_patches)).bool()
>>> outputs = model(pixel_values, bool_masked_pos=bool_masked_pos)
>>> loss, reconstructed_pixel_values = outputs.loss, outputs.logits
>>> list(reconstructed_pixel_values.shape)
[1, 3, 224, 224]
```"""
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
outputs = self.swin(
pixel_values,
bool_masked_pos=bool_masked_pos,
head_mask=head_mask,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
)
sequence_output = outputs[0]
# Reshape to (batch_size, num_channels, height, width)
sequence_output = sequence_output.transpose(1, 2)
batch_size, num_channels, sequence_length = sequence_output.shape
height = width = int(sequence_length**0.5)
sequence_output = sequence_output.reshape(batch_size, num_channels, height, width)
# Reconstruct pixel values
reconstructed_pixel_values = self.decoder(sequence_output)
masked_im_loss = None
if bool_masked_pos is not None:
size = self.config.image_size // self.config.patch_size
bool_masked_pos = bool_masked_pos.reshape(-1, size, size)
mask = (
bool_masked_pos.repeat_interleave(self.config.patch_size, 1)
.repeat_interleave(self.config.patch_size, 2)
.unsqueeze(1)
.contiguous()
)
reconstruction_loss = nn.functional.l1_loss(pixel_values, reconstructed_pixel_values, reduction="none")
masked_im_loss = (reconstruction_loss * mask).sum() / (mask.sum() + 1e-5) / self.config.num_channels
if not return_dict:
output = (reconstructed_pixel_values,) + outputs[2:]
return ((masked_im_loss,) + output) if masked_im_loss is not None else output
return SwinMaskedImageModelingOutput(
loss=masked_im_loss,
logits=reconstructed_pixel_values,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
reshaped_hidden_states=outputs.reshaped_hidden_states,
)
@add_start_docstrings(
"""
Swin Model transformer with an image classification head on top (a linear layer on top of the final hidden state of
the [CLS] token) e.g. for ImageNet.
""",
SWIN_START_DOCSTRING,
)
class SwinForImageClassification(SwinPreTrainedModel):
def __init__(self, config):
super().__init__(config)
self.num_labels = config.num_labels
self.swin = SwinModel(config)
# Classifier head
self.classifier = (
nn.Linear(self.swin.num_features, config.num_labels) if config.num_labels > 0 else nn.Identity()
)
# Initialize weights and apply final processing
self.post_init()
@add_start_docstrings_to_model_forward(SWIN_INPUTS_DOCSTRING)
@add_code_sample_docstrings(
processor_class=_FEAT_EXTRACTOR_FOR_DOC,
checkpoint=_IMAGE_CLASS_CHECKPOINT,
output_type=SwinImageClassifierOutput,
config_class=_CONFIG_FOR_DOC,
expected_output=_IMAGE_CLASS_EXPECTED_OUTPUT,
)
def forward(
self,
pixel_values=None,
head_mask=None,
labels=None,
output_attentions=None,
output_hidden_states=None,
return_dict=None,
):
r"""
labels (`torch.LongTensor` of shape `(batch_size,)`, *optional*):
Labels for computing the image classification/regression loss. Indices should be in `[0, ...,
config.num_labels - 1]`. If `config.num_labels == 1` a regression loss is computed (Mean-Square loss), If
`config.num_labels > 1` a classification loss is computed (Cross-Entropy).
"""
return_dict = return_dict if return_dict is not None else self.config.use_return_dict
outputs = self.swin(
pixel_values,
head_mask=head_mask,
output_attentions=output_attentions,
output_hidden_states=output_hidden_states,
return_dict=return_dict,
)
pooled_output = outputs[1]
logits = self.classifier(pooled_output)
loss = None
if labels is not None:
if self.config.problem_type is None:
if self.num_labels == 1:
self.config.problem_type = "regression"
elif self.num_labels > 1 and (labels.dtype == torch.long or labels.dtype == torch.int):
self.config.problem_type = "single_label_classification"
else:
self.config.problem_type = "multi_label_classification"
if self.config.problem_type == "regression":
loss_fct = MSELoss()
if self.num_labels == 1:
loss = loss_fct(logits.squeeze(), labels.squeeze())
else:
loss = loss_fct(logits, labels)
elif self.config.problem_type == "single_label_classification":
loss_fct = CrossEntropyLoss()
loss = loss_fct(logits.view(-1, self.num_labels), labels.view(-1))
elif self.config.problem_type == "multi_label_classification":
loss_fct = BCEWithLogitsLoss()
loss = loss_fct(logits, labels)
if not return_dict:
output = (logits,) + outputs[2:]
return ((loss,) + output) if loss is not None else output
return SwinImageClassifierOutput(
loss=loss,
logits=logits,
hidden_states=outputs.hidden_states,
attentions=outputs.attentions,
reshaped_hidden_states=outputs.reshaped_hidden_states,
)