diff --git a/configs/faster_rcnn/_base_/faster_rcnn_swin_transformer.yml b/configs/faster_rcnn/_base_/faster_rcnn_swin_transformer.yml new file mode 100644 index 0000000000000000000000000000000000000000..918fc52f1b3b9f4b92c5fd31c971bb4949f01cc1 --- /dev/null +++ b/configs/faster_rcnn/_base_/faster_rcnn_swin_transformer.yml @@ -0,0 +1,73 @@ +architecture: FasterRCNN + +FasterRCNN: + backbone: SwinTransformer + neck: FPN + rpn_head: RPNHead + bbox_head: BBoxHead + bbox_post_process: BBoxPostProcess + +SwinTransformer: + embed_dim: 96 + depths: [2, 2, 6, 2] + num_heads: [3, 6, 12, 24] + window_size: 7 + ape: false + drop_path_rate: 0.1 + patch_norm: true + out_indices: [0,1,2,3] + drop_path_rate: 0.1 + pretrained: https://paddledet.bj.bcebos.com/models/pretrained/swin_tiny_patch4_window7_224.pdparams + +FPN: + out_channel: 256 + +RPNHead: + anchor_generator: + aspect_ratios: [0.5, 1.0, 2.0] + anchor_sizes: [[32], [64], [128], [256], [512]] + strides: [4, 8, 16, 32, 64] + rpn_target_assign: + batch_size_per_im: 256 + fg_fraction: 0.5 + negative_overlap: 0.3 + positive_overlap: 0.7 + use_random: True + train_proposal: + min_size: 0.0 + nms_thresh: 0.7 + pre_nms_top_n: 2000 + post_nms_top_n: 1000 + topk_after_collect: True + test_proposal: + min_size: 0.0 + nms_thresh: 0.7 + pre_nms_top_n: 1000 + post_nms_top_n: 1000 + + +BBoxHead: + head: TwoFCHead + roi_extractor: + resolution: 7 + sampling_ratio: 0 + aligned: True + bbox_assigner: BBoxAssigner + +BBoxAssigner: + batch_size_per_im: 512 + bg_thresh: 0.5 + fg_thresh: 0.5 + fg_fraction: 0.25 + use_random: True + +TwoFCHead: + out_channel: 1024 + +BBoxPostProcess: + decode: RCNNBox + nms: + name: MultiClassNMS + keep_top_k: 100 + score_threshold: 0.05 + nms_threshold: 0.5 diff --git a/configs/faster_rcnn/_base_/faster_rcnn_swin_transformer_reader.yml b/configs/faster_rcnn/_base_/faster_rcnn_swin_transformer_reader.yml new file mode 100644 index 0000000000000000000000000000000000000000..e1140df18ce44f88afbc56bddb7676a9751ed8b8 --- /dev/null +++ b/configs/faster_rcnn/_base_/faster_rcnn_swin_transformer_reader.yml @@ -0,0 +1,41 @@ +worker_num: 2 +TrainReader: + sample_transforms: + - Decode: {} + - RandomResizeCrop: {resizes: [400, 500, 600], cropsizes: [[384, 600], ], prob: 0.5} + - RandomResize: {target_size: [[480, 1333], [512, 1333], [544, 1333], [576, 1333], [608, 1333], [640, 1333], [672, 1333], [704, 1333], [736, 1333], [768, 1333], [800, 1333]], keep_ratio: True, interp: 2} + - RandomFlip: {prob: 0.5} + - NormalizeImage: {is_scale: true, mean: [0.485,0.456,0.406], std: [0.229, 0.224,0.225]} + - Permute: {} + batch_transforms: + - PadBatch: {pad_to_stride: 32} + batch_size: 2 + shuffle: true + drop_last: true + collate_batch: false + +EvalReader: + sample_transforms: + - Decode: {} + - Resize: {interp: 2, target_size: [800, 1333], keep_ratio: True} + - NormalizeImage: {is_scale: true, mean: [0.485,0.456,0.406], std: [0.229, 0.224,0.225]} + - Permute: {} + batch_transforms: + - PadBatch: {pad_to_stride: 32} + batch_size: 1 + shuffle: false + drop_last: false + drop_empty: false + + +TestReader: + sample_transforms: + - Decode: {} + - Resize: {interp: 2, target_size: [800, 1333], keep_ratio: True} + - NormalizeImage: {is_scale: true, mean: [0.485,0.456,0.406], std: [0.229, 0.224,0.225]} + - Permute: {} + batch_transforms: + - PadBatch: {pad_to_stride: 32} + batch_size: 1 + shuffle: false + drop_last: false diff --git a/configs/faster_rcnn/_base_/optimizer_swin_transformer_1x.yml b/configs/faster_rcnn/_base_/optimizer_swin_transformer_1x.yml new file mode 100644 index 0000000000000000000000000000000000000000..5ac26b593be7df5724d840b3d16d93dc07a4ac83 --- /dev/null +++ b/configs/faster_rcnn/_base_/optimizer_swin_transformer_1x.yml @@ -0,0 +1,17 @@ +epoch: 12 + +LearningRate: + base_lr: 0.0001 + schedulers: + - !PiecewiseDecay + gamma: 0.1 + milestones: [8, 11] + - !LinearWarmup + start_factor: 0.1 + steps: 1000 + +OptimizerBuilder: + clip_grad_by_norm: 1.0 + optimizer: + type: AdamW + weight_decay: 0.05 diff --git a/configs/faster_rcnn/faster_rcnn_swin_transformer_tiny_1x_coco.yml b/configs/faster_rcnn/faster_rcnn_swin_transformer_tiny_1x_coco.yml new file mode 100644 index 0000000000000000000000000000000000000000..caaa5391e514963c701b0ed47a2d8e9e2a4f308f --- /dev/null +++ b/configs/faster_rcnn/faster_rcnn_swin_transformer_tiny_1x_coco.yml @@ -0,0 +1,8 @@ +_BASE_: [ + '../datasets/coco_detection.yml', + '../runtime.yml', + '_base_/optimizer_swin_transformer_1x.yml', + '_base_/faster_rcnn_swin_transformer.yml', + '_base_/faster_rcnn_swin_transformer_reader.yml', +] +weights: output/faster_swin_transformer_tiny_1x/model_final diff --git a/configs/faster_rcnn/faster_rcnn_swin_transformer_tiny_2x_coco.yml b/configs/faster_rcnn/faster_rcnn_swin_transformer_tiny_2x_coco.yml new file mode 100644 index 0000000000000000000000000000000000000000..8f793cb7d88e98f4eed7f2bdf5ac5396d5220467 --- /dev/null +++ b/configs/faster_rcnn/faster_rcnn_swin_transformer_tiny_2x_coco.yml @@ -0,0 +1,22 @@ +_BASE_: [ + 'faster_rcnn_swin_transformer_tiny_1x_coco.yml', +] +weights: output/faster_swin_transformer_tiny_2x/model_final + +epoch: 24 + +LearningRate: + base_lr: 0.0001 + schedulers: + - !PiecewiseDecay + gamma: 0.1 + milestones: [16, 22] + - !LinearWarmup + start_factor: 0.1 + steps: 1000 + +OptimizerBuilder: + clip_grad_by_norm: 1.0 + optimizer: + type: AdamW + weight_decay: 0.05 diff --git a/configs/faster_rcnn/faster_rcnn_swin_transformer_tiny_3x_coco.yml b/configs/faster_rcnn/faster_rcnn_swin_transformer_tiny_3x_coco.yml new file mode 100644 index 0000000000000000000000000000000000000000..fbf46bcbab927a5fa5732ffd468d1f82f19d88e9 --- /dev/null +++ b/configs/faster_rcnn/faster_rcnn_swin_transformer_tiny_3x_coco.yml @@ -0,0 +1,22 @@ +_BASE_: [ + 'faster_rcnn_swin_transformer_tiny_1x_coco.yml', +] +weights: output/faster_swin_transformer_tiny_3x/model_final + +epoch: 36 + +LearningRate: + base_lr: 0.0001 + schedulers: + - !PiecewiseDecay + gamma: 0.1 + milestones: [24, 33] + - !LinearWarmup + start_factor: 0.1 + steps: 1000 + +OptimizerBuilder: + clip_grad_by_norm: 1.0 + optimizer: + type: AdamW + weight_decay: 0.05 diff --git a/ppdet/modeling/backbones/__init__.py b/ppdet/modeling/backbones/__init__.py index 58fd371389a11620e069186c851b4f377e4105d1..4b4ce27f8bd80e883766a67a194365305e442cc4 100644 --- a/ppdet/modeling/backbones/__init__.py +++ b/ppdet/modeling/backbones/__init__.py @@ -25,6 +25,7 @@ from . import senet from . import res2net from . import dla from . import shufflenet_v2 +from . import swin_transformer from .vgg import * from .resnet import * @@ -39,3 +40,4 @@ from .senet import * from .res2net import * from .dla import * from .shufflenet_v2 import * +from .swin_transformer import * diff --git a/ppdet/modeling/backbones/swin_transformer.py b/ppdet/modeling/backbones/swin_transformer.py new file mode 100644 index 0000000000000000000000000000000000000000..f4411b2f527f1e968c27be42b34f954f772d1e53 --- /dev/null +++ b/ppdet/modeling/backbones/swin_transformer.py @@ -0,0 +1,738 @@ +# Copyright (c) 2021 PaddlePaddle Authors. 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. + +import paddle +import paddle.nn as nn +import paddle.nn.functional as F +from paddle.nn.initializer import TruncatedNormal, Constant, Assign +from ppdet.modeling.shape_spec import ShapeSpec +from ppdet.core.workspace import register, serializable +import numpy as np + +# Common initializations +ones_ = Constant(value=1.) +zeros_ = Constant(value=0.) +trunc_normal_ = TruncatedNormal(std=.02) + + +# Common Functions +def to_2tuple(x): + return tuple([x] * 2) + + +def add_parameter(layer, datas, name=None): + parameter = layer.create_parameter( + shape=(datas.shape), default_initializer=Assign(datas)) + if name: + layer.add_parameter(name, parameter) + return parameter + + +# Common Layers +def drop_path(x, drop_prob=0., training=False): + """ + Drop paths (Stochastic Depth) per sample (when applied in main path of residual blocks). + the original name is misleading as 'Drop Connect' is a different form of dropout in a separate paper... + See discussion: https://github.com/tensorflow/tpu/issues/494#issuecomment-532968956 ... + """ + if drop_prob == 0. or not training: + return x + keep_prob = paddle.to_tensor(1 - drop_prob) + shape = (paddle.shape(x)[0], ) + (1, ) * (x.ndim - 1) + random_tensor = keep_prob + paddle.rand(shape, dtype=x.dtype) + random_tensor = paddle.floor(random_tensor) # binarize + output = x.divide(keep_prob) * random_tensor + return output + + +class DropPath(nn.Layer): + def __init__(self, drop_prob=None): + super(DropPath, self).__init__() + self.drop_prob = drop_prob + + def forward(self, x): + return drop_path(x, self.drop_prob, self.training) + + +class Identity(nn.Layer): + def __init__(self): + super(Identity, self).__init__() + + def forward(self, input): + return input + + +class Mlp(nn.Layer): + def __init__(self, + in_features, + hidden_features=None, + out_features=None, + act_layer=nn.GELU, + drop=0.): + super().__init__() + out_features = out_features or in_features + hidden_features = hidden_features or in_features + self.fc1 = nn.Linear(in_features, hidden_features) + self.act = act_layer() + self.fc2 = nn.Linear(hidden_features, out_features) + self.drop = nn.Dropout(drop) + + def forward(self, x): + x = self.fc1(x) + x = self.act(x) + x = self.drop(x) + x = self.fc2(x) + x = self.drop(x) + return x + + +def window_partition(x, window_size): + """ + Args: + x: (B, H, W, C) + window_size (int): window size + Returns: + windows: (num_windows*B, window_size, window_size, C) + """ + B, H, W, C = x.shape + x = x.reshape( + [B, H // window_size, window_size, W // window_size, window_size, C]) + windows = x.transpose([0, 1, 3, 2, 4, 5]).reshape( + [-1, window_size, window_size, C]) + return windows + + +def window_reverse(windows, window_size, H, W): + """ + Args: + windows: (num_windows*B, window_size, window_size, C) + window_size (int): Window size + H (int): Height of image + W (int): Width of image + Returns: + x: (B, H, W, C) + """ + B = int(windows.shape[0] / (H * W / window_size / window_size)) + x = windows.reshape( + [B, H // window_size, W // window_size, window_size, window_size, -1]) + x = x.transpose([0, 1, 3, 2, 4, 5]).reshape([B, H, W, -1]) + return x + + +class WindowAttention(nn.Layer): + """ Window based multi-head self attention (W-MSA) module with relative position bias. + It supports both of shifted and non-shifted window. + + Args: + dim (int): Number of input channels. + window_size (tuple[int]): The height and width of the window. + num_heads (int): Number of attention heads. + qkv_bias (bool, optional): If True, add a learnable bias to query, key, value. Default: True + qk_scale (float | None, optional): Override default qk scale of head_dim ** -0.5 if set + attn_drop (float, optional): Dropout ratio of attention weight. Default: 0.0 + proj_drop (float, optional): Dropout ratio of output. Default: 0.0 + """ + + def __init__(self, + dim, + window_size, + num_heads, + qkv_bias=True, + qk_scale=None, + attn_drop=0., + proj_drop=0.): + + super().__init__() + self.dim = dim + self.window_size = window_size # Wh, Ww + self.num_heads = num_heads + head_dim = dim // num_heads + self.scale = qk_scale or head_dim**-0.5 + + # define a parameter table of relative position bias + self.relative_position_bias_table = add_parameter( + self, + paddle.zeros(((2 * window_size[0] - 1) * (2 * window_size[1] - 1), + num_heads))) # 2*Wh-1 * 2*Ww-1, nH + + # get pair-wise relative position index for each token inside the window + coords_h = paddle.arange(self.window_size[0]) + coords_w = paddle.arange(self.window_size[1]) + coords = paddle.stack(paddle.meshgrid( + [coords_h, coords_w])) # 2, Wh, Ww + coords_flatten = paddle.flatten(coords, 1) # 2, Wh*Ww + coords_flatten_1 = coords_flatten.unsqueeze(axis=2) + coords_flatten_2 = coords_flatten.unsqueeze(axis=1) + relative_coords = coords_flatten_1 - coords_flatten_2 + relative_coords = relative_coords.transpose( + [1, 2, 0]) # Wh*Ww, Wh*Ww, 2 + relative_coords[:, :, 0] += self.window_size[ + 0] - 1 # shift to start from 0 + relative_coords[:, :, 1] += self.window_size[1] - 1 + relative_coords[:, :, 0] *= 2 * self.window_size[1] - 1 + self.relative_position_index = relative_coords.sum(-1) # Wh*Ww, Wh*Ww + self.register_buffer("relative_position_index", + self.relative_position_index) + + self.qkv = nn.Linear(dim, dim * 3, bias_attr=qkv_bias) + self.attn_drop = nn.Dropout(attn_drop) + self.proj = nn.Linear(dim, dim) + self.proj_drop = nn.Dropout(proj_drop) + + trunc_normal_(self.relative_position_bias_table) + self.softmax = nn.Softmax(axis=-1) + + def forward(self, x, mask=None): + """ Forward function. + Args: + x: input features with shape of (num_windows*B, N, C) + mask: (0/-inf) mask with shape of (num_windows, Wh*Ww, Wh*Ww) or None + """ + B_, N, C = x.shape + qkv = self.qkv(x).reshape( + [B_, N, 3, self.num_heads, C // self.num_heads]).transpose( + [2, 0, 3, 1, 4]) + q, k, v = qkv[0], qkv[1], qkv[2] + + q = q * self.scale + attn = paddle.mm(q, k.transpose([0, 1, 3, 2])) + + index = self.relative_position_index.reshape([-1]) + + relative_position_bias = paddle.index_select( + self.relative_position_bias_table, index) + relative_position_bias = relative_position_bias.reshape([ + self.window_size[0] * self.window_size[1], + self.window_size[0] * self.window_size[1], -1 + ]) # Wh*Ww,Wh*Ww,nH + relative_position_bias = relative_position_bias.transpose( + [2, 0, 1]) # nH, Wh*Ww, Wh*Ww + attn = attn + relative_position_bias.unsqueeze(0) + + if mask is not None: + nW = mask.shape[0] + attn = attn.reshape([B_ // nW, nW, self.num_heads, N, N + ]) + mask.unsqueeze(1).unsqueeze(0) + attn = attn.reshape([-1, self.num_heads, N, N]) + attn = self.softmax(attn) + else: + attn = self.softmax(attn) + + attn = self.attn_drop(attn) + + # x = (attn @ v).transpose(1, 2).reshape([B_, N, C]) + x = paddle.mm(attn, v).transpose([0, 2, 1, 3]).reshape([B_, N, C]) + x = self.proj(x) + x = self.proj_drop(x) + return x + + +class SwinTransformerBlock(nn.Layer): + """ Swin Transformer Block. + Args: + dim (int): Number of input channels. + num_heads (int): Number of attention heads. + window_size (int): Window size. + shift_size (int): Shift size for SW-MSA. + mlp_ratio (float): Ratio of mlp hidden dim to embedding dim. + qkv_bias (bool, optional): If True, add a learnable bias to query, key, value. Default: True + qk_scale (float | None, optional): Override default qk scale of head_dim ** -0.5 if set. + drop (float, optional): Dropout rate. Default: 0.0 + attn_drop (float, optional): Attention dropout rate. Default: 0.0 + drop_path (float, optional): Stochastic depth rate. Default: 0.0 + act_layer (nn.Layer, optional): Activation layer. Default: nn.GELU + norm_layer (nn.Layer, optional): Normalization layer. Default: nn.LayerNorm + """ + + def __init__(self, + dim, + num_heads, + window_size=7, + shift_size=0, + mlp_ratio=4., + qkv_bias=True, + qk_scale=None, + drop=0., + attn_drop=0., + drop_path=0., + act_layer=nn.GELU, + norm_layer=nn.LayerNorm): + super().__init__() + self.dim = dim + self.num_heads = num_heads + self.window_size = window_size + self.shift_size = shift_size + self.mlp_ratio = mlp_ratio + assert 0 <= self.shift_size < self.window_size, "shift_size must in 0-window_size" + + self.norm1 = norm_layer(dim) + self.attn = WindowAttention( + dim, + window_size=to_2tuple(self.window_size), + num_heads=num_heads, + qkv_bias=qkv_bias, + qk_scale=qk_scale, + attn_drop=attn_drop, + proj_drop=drop) + + self.drop_path = DropPath(drop_path) if drop_path > 0. else Identity() + self.norm2 = norm_layer(dim) + mlp_hidden_dim = int(dim * mlp_ratio) + self.mlp = Mlp(in_features=dim, + hidden_features=mlp_hidden_dim, + act_layer=act_layer, + drop=drop) + + self.H = None + self.W = None + + def forward(self, x, mask_matrix): + """ Forward function. + Args: + x: Input feature, tensor size (B, H*W, C). + H, W: Spatial resolution of the input feature. + mask_matrix: Attention mask for cyclic shift. + """ + B, L, C = x.shape + H, W = self.H, self.W + assert L == H * W, "input feature has wrong size" + + shortcut = x + x = self.norm1(x) + x = x.reshape([B, H, W, C]) + + # pad feature maps to multiples of window size + pad_l = pad_t = 0 + pad_r = (self.window_size - W % self.window_size) % self.window_size + pad_b = (self.window_size - H % self.window_size) % self.window_size + x = F.pad(x, [0, pad_l, 0, pad_b, 0, pad_r, 0, pad_t]) + _, Hp, Wp, _ = x.shape + + # cyclic shift + if self.shift_size > 0: + shifted_x = paddle.roll( + x, shifts=(-self.shift_size, -self.shift_size), axis=(1, 2)) + attn_mask = mask_matrix + else: + shifted_x = x + attn_mask = None + + # partition windows + x_windows = window_partition( + shifted_x, self.window_size) # nW*B, window_size, window_size, C + x_windows = x_windows.reshape( + [-1, self.window_size * self.window_size, + C]) # nW*B, window_size*window_size, C + + # W-MSA/SW-MSA + attn_windows = self.attn( + x_windows, mask=attn_mask) # nW*B, window_size*window_size, C + + # merge windows + attn_windows = attn_windows.reshape( + [-1, self.window_size, self.window_size, C]) + shifted_x = window_reverse(attn_windows, self.window_size, Hp, + Wp) # B H' W' C + + # reverse cyclic shift + if self.shift_size > 0: + x = paddle.roll( + shifted_x, + shifts=(self.shift_size, self.shift_size), + axis=(1, 2)) + else: + x = shifted_x + + if pad_r > 0 or pad_b > 0: + x = x[:, :H, :W, :] + + x = x.reshape([B, H * W, C]) + + # FFN + x = shortcut + self.drop_path(x) + x = x + self.drop_path(self.mlp(self.norm2(x))) + + return x + + +class PatchMerging(nn.Layer): + r""" Patch Merging Layer. + Args: + dim (int): Number of input channels. + norm_layer (nn.Layer, optional): Normalization layer. Default: nn.LayerNorm + """ + + def __init__(self, dim, norm_layer=nn.LayerNorm): + super().__init__() + self.dim = dim + self.reduction = nn.Linear(4 * dim, 2 * dim, bias_attr=False) + self.norm = norm_layer(4 * dim) + + def forward(self, x, H, W): + """ Forward function. + Args: + x: Input feature, tensor size (B, H*W, C). + H, W: Spatial resolution of the input feature. + """ + B, L, C = x.shape + assert L == H * W, "input feature has wrong size" + + x = x.reshape([B, H, W, C]) + + # padding + pad_input = (H % 2 == 1) or (W % 2 == 1) + if pad_input: + x = F.pad(x, [0, 0, 0, W % 2, 0, H % 2]) + + x0 = x[:, 0::2, 0::2, :] # B H/2 W/2 C + x1 = x[:, 1::2, 0::2, :] # B H/2 W/2 C + x2 = x[:, 0::2, 1::2, :] # B H/2 W/2 C + x3 = x[:, 1::2, 1::2, :] # B H/2 W/2 C + x = paddle.concat([x0, x1, x2, x3], -1) # B H/2 W/2 4*C + x = x.reshape([B, H * W // 4, 4 * C]) # B H/2*W/2 4*C + + x = self.norm(x) + x = self.reduction(x) + + return x + + +class BasicLayer(nn.Layer): + """ A basic Swin Transformer layer for one stage. + Args: + dim (int): Number of input channels. + input_resolution (tuple[int]): Input resolution. + depth (int): Number of blocks. + num_heads (int): Number of attention heads. + window_size (int): Local window size. + mlp_ratio (float): Ratio of mlp hidden dim to embedding dim. + qkv_bias (bool, optional): If True, add a learnable bias to query, key, value. Default: True + qk_scale (float | None, optional): Override default qk scale of head_dim ** -0.5 if set. + drop (float, optional): Dropout rate. Default: 0.0 + attn_drop (float, optional): Attention dropout rate. Default: 0.0 + drop_path (float | tuple[float], optional): Stochastic depth rate. Default: 0.0 + norm_layer (nn.Layer, optional): Normalization layer. Default: nn.LayerNorm + downsample (nn.Layer | None, optional): Downsample layer at the end of the layer. Default: None + """ + + def __init__(self, + dim, + depth, + num_heads, + window_size=7, + mlp_ratio=4., + qkv_bias=True, + qk_scale=None, + drop=0., + attn_drop=0., + drop_path=0., + norm_layer=nn.LayerNorm, + downsample=None): + super().__init__() + self.window_size = window_size + self.shift_size = window_size // 2 + self.depth = depth + + # build blocks + self.blocks = nn.LayerList([ + SwinTransformerBlock( + dim=dim, + num_heads=num_heads, + window_size=window_size, + shift_size=0 if (i % 2 == 0) else window_size // 2, + mlp_ratio=mlp_ratio, + qkv_bias=qkv_bias, + qk_scale=qk_scale, + drop=drop, + attn_drop=attn_drop, + drop_path=drop_path[i] + if isinstance(drop_path, np.ndarray) else drop_path, + norm_layer=norm_layer) for i in range(depth) + ]) + + # patch merging layer + if downsample is not None: + self.downsample = downsample(dim=dim, norm_layer=norm_layer) + else: + self.downsample = None + + def forward(self, x, H, W): + """ Forward function. + Args: + x: Input feature, tensor size (B, H*W, C). + H, W: Spatial resolution of the input feature. + """ + + # calculate attention mask for SW-MSA + Hp = int(np.ceil(H / self.window_size)) * self.window_size + Wp = int(np.ceil(W / self.window_size)) * self.window_size + img_mask = paddle.fluid.layers.zeros( + [1, Hp, Wp, 1], dtype='float32') # 1 Hp Wp 1 + h_slices = (slice(0, -self.window_size), + slice(-self.window_size, -self.shift_size), + slice(-self.shift_size, None)) + w_slices = (slice(0, -self.window_size), + slice(-self.window_size, -self.shift_size), + slice(-self.shift_size, None)) + cnt = 0 + for h in h_slices: + for w in w_slices: + img_mask[:, h, w, :] = cnt + cnt += 1 + mask_windows = window_partition( + img_mask, self.window_size) # nW, window_size, window_size, 1 + mask_windows = mask_windows.reshape( + [-1, self.window_size * self.window_size]) + attn_mask = mask_windows.unsqueeze(1) - mask_windows.unsqueeze(2) + huns = -100.0 * paddle.ones_like(attn_mask) + attn_mask = huns * (attn_mask != 0).astype("float32") + + for blk in self.blocks: + blk.H, blk.W = H, W + x = blk(x, attn_mask) + if self.downsample is not None: + x_down = self.downsample(x, H, W) + Wh, Ww = (H + 1) // 2, (W + 1) // 2 + return x, H, W, x_down, Wh, Ww + else: + return x, H, W, x, H, W + + +class PatchEmbed(nn.Layer): + """ Image to Patch Embedding + Args: + patch_size (int): Patch token size. Default: 4. + in_chans (int): Number of input image channels. Default: 3. + embed_dim (int): Number of linear projection output channels. Default: 96. + norm_layer (nn.Layer, optional): Normalization layer. Default: None + """ + + def __init__(self, patch_size=4, in_chans=3, embed_dim=96, norm_layer=None): + super().__init__() + patch_size = to_2tuple(patch_size) + self.patch_size = patch_size + + self.in_chans = in_chans + self.embed_dim = embed_dim + + self.proj = nn.Conv2D( + in_chans, embed_dim, kernel_size=patch_size, stride=patch_size) + if norm_layer is not None: + self.norm = norm_layer(embed_dim) + else: + self.norm = None + + def forward(self, x): + B, C, H, W = x.shape + # assert [H, W] == self.img_size[:2], "Input image size ({H}*{W}) doesn't match model ({}*{}).".format(H, W, self.img_size[0], self.img_size[1]) + if W % self.patch_size[1] != 0: + x = F.pad(x, [0, self.patch_size[1] - W % self.patch_size[1]]) + if H % self.patch_size[0] != 0: + x = F.pad(x, [0, 0, 0, self.patch_size[0] - H % self.patch_size[0]]) + + x = self.proj(x) + if self.norm is not None: + _, _, Wh, Ww = x.shape + x = x.flatten(2).transpose([0, 2, 1]) + x = self.norm(x) + x = x.transpose([0, 2, 1]).reshape([-1, self.embed_dim, Wh, Ww]) + + return x + + +@register +@serializable +class SwinTransformer(nn.Layer): + """ Swin Transformer + A PaddlePaddle impl of : `Swin Transformer: Hierarchical Vision Transformer using Shifted Windows` - + https://arxiv.org/pdf/2103.14030 + + Args: + img_size (int | tuple(int)): Input image size. Default 224 + patch_size (int | tuple(int)): Patch size. Default: 4 + in_chans (int): Number of input image channels. Default: 3 + num_classes (int): Number of classes for classification head. Default: 1000 + embed_dim (int): Patch embedding dimension. Default: 96 + depths (tuple(int)): Depth of each Swin Transformer layer. + num_heads (tuple(int)): Number of attention heads in different layers. + window_size (int): Window size. Default: 7 + mlp_ratio (float): Ratio of mlp hidden dim to embedding dim. Default: 4 + qkv_bias (bool): If True, add a learnable bias to query, key, value. Default: True + qk_scale (float): Override default qk scale of head_dim ** -0.5 if set. Default: None + drop_rate (float): Dropout rate. Default: 0 + attn_drop_rate (float): Attention dropout rate. Default: 0 + drop_path_rate (float): Stochastic depth rate. Default: 0.1 + norm_layer (nn.Layer): Normalization layer. Default: nn.LayerNorm. + ape (bool): If True, add absolute position embedding to the patch embedding. Default: False + patch_norm (bool): If True, add normalization after patch embedding. Default: True + """ + + def __init__(self, + pretrain_img_size=224, + patch_size=4, + in_chans=3, + embed_dim=96, + depths=[2, 2, 6, 2], + num_heads=[3, 6, 12, 24], + window_size=7, + mlp_ratio=4., + qkv_bias=True, + qk_scale=None, + drop_rate=0., + attn_drop_rate=0., + drop_path_rate=0.2, + norm_layer=nn.LayerNorm, + ape=False, + patch_norm=True, + out_indices=(0, 1, 2, 3), + frozen_stages=-1, + pretrained=None): + super(SwinTransformer, self).__init__() + + self.pretrain_img_size = pretrain_img_size + self.num_layers = len(depths) + self.embed_dim = embed_dim + self.ape = ape + self.patch_norm = patch_norm + self.out_indices = out_indices + self.frozen_stages = frozen_stages + + # split image into non-overlapping patches + self.patch_embed = PatchEmbed( + patch_size=patch_size, + in_chans=in_chans, + embed_dim=embed_dim, + norm_layer=norm_layer if self.patch_norm else None) + + # absolute position embedding + if self.ape: + pretrain_img_size = to_2tuple(pretrain_img_size) + patch_size = to_2tuple(patch_size) + patches_resolution = [ + pretrain_img_size[0] // patch_size[0], + pretrain_img_size[1] // patch_size[1] + ] + + self.absolute_pos_embed = add_parameter( + self, + paddle.zeros((1, embed_dim, patches_resolution[0], + patches_resolution[1]))) + trunc_normal_(self.absolute_pos_embed) + + self.pos_drop = nn.Dropout(p=drop_rate) + + # stochastic depth + dpr = np.linspace(0, drop_path_rate, + sum(depths)) # stochastic depth decay rule + + # build layers + self.layers = nn.LayerList() + for i_layer in range(self.num_layers): + layer = BasicLayer( + dim=int(embed_dim * 2**i_layer), + depth=depths[i_layer], + num_heads=num_heads[i_layer], + window_size=window_size, + mlp_ratio=mlp_ratio, + qkv_bias=qkv_bias, + qk_scale=qk_scale, + drop=drop_rate, + attn_drop=attn_drop_rate, + drop_path=dpr[sum(depths[:i_layer]):sum(depths[:i_layer + 1])], + norm_layer=norm_layer, + downsample=PatchMerging + if (i_layer < self.num_layers - 1) else None) + self.layers.append(layer) + + num_features = [int(embed_dim * 2**i) for i in range(self.num_layers)] + self.num_features = num_features + + # add a norm layer for each output + for i_layer in out_indices: + layer = norm_layer(num_features[i_layer]) + layer_name = f'norm{i_layer}' + self.add_sublayer(layer_name, layer) + + self.apply(self._init_weights) + self._freeze_stages() + if pretrained: + if 'http' in pretrained: #URL + path = paddle.utils.download.get_weights_path_from_url( + pretrained) + else: #model in local path + path = pretrained + self.set_state_dict(paddle.load(path)) + print('###################################################') + print('###############Success load the mode###############') + print('###################################################') + + def _freeze_stages(self): + if self.frozen_stages >= 0: + self.patch_embed.eval() + for param in self.patch_embed.parameters(): + param.requires_grad = False + + if self.frozen_stages >= 1 and self.ape: + self.absolute_pos_embed.requires_grad = False + + if self.frozen_stages >= 2: + self.pos_drop.eval() + for i in range(0, self.frozen_stages - 1): + m = self.layers[i] + m.eval() + for param in m.parameters(): + param.requires_grad = False + + def _init_weights(self, m): + if isinstance(m, nn.Linear): + trunc_normal_(m.weight) + if isinstance(m, nn.Linear) and m.bias is not None: + zeros_(m.bias) + elif isinstance(m, nn.LayerNorm): + zeros_(m.bias) + ones_(m.weight) + + def forward(self, x): + """Forward function.""" + x = self.patch_embed(x['image']) + _, _, Wh, Ww = x.shape + if self.ape: + # interpolate the position embedding to the corresponding size + absolute_pos_embed = F.interpolate( + self.absolute_pos_embed, size=(Wh, Ww), mode='bicubic') + x = (x + absolute_pos_embed).flatten(2).transpose([0, 2, 1]) + else: + x = x.flatten(2).transpose([0, 2, 1]) + x = self.pos_drop(x) + outs = [] + for i in range(self.num_layers): + layer = self.layers[i] + x_out, H, W, x, Wh, Ww = layer(x, Wh, Ww) + if i in self.out_indices: + norm_layer = getattr(self, f'norm{i}') + x_out = norm_layer(x_out) + out = x_out.reshape((-1, H, W, self.num_features[i])).transpose( + (0, 3, 1, 2)) + outs.append(out) + + return tuple(outs) + + @property + def out_shape(self): + out_strides = [4, 8, 16, 32] + return [ + ShapeSpec( + channels=self.num_features[i], stride=out_strides[i]) + for i in self.out_indices + ]