给出不同的注意力模块如下：import torch
import torch.nn as nn

#######################
#    - SAB（空间注意力）：适用于提升空间结构的感知能力。
#    - PAB（像素注意力）：适用于细粒度像素级特征重加权。
#    - CAB（通道注意力）：适用于增强通道间的协同作用。
##########################################################################
def conv(in_channels, out_channels, kernel_size, bias=False, stride=1):
    layer = nn.Conv2d(in_channels, out_channels, kernel_size, padding=(kernel_size // 2), bias=bias, stride=stride)
    return layer


def conv3x3(in_chn, out_chn, bias=True):
    layer = nn.Conv2d(in_chn, out_chn, kernel_size=3, stride=1, padding=1, bias=bias)
    return layer


def conv_down(in_chn, out_chn, bias=False):
    layer = nn.Conv2d(in_chn, out_chn, kernel_size=4, stride=2, padding=1, bias=bias)
    return layer

##########################################################################
## Supervised Attention Module (RAM)
class SAM(nn.Module):
    def __init__(self, n_feat, kernel_size, bias):
        super(SAM, self).__init__()
        self.conv1 = conv(n_feat, n_feat, kernel_size, bias=bias)
        self.conv2 = conv(n_feat, 3, kernel_size, bias=bias)
        self.conv3 = conv(3, n_feat, kernel_size, bias=bias)

    def forward(self, x, x_img):
        x1 = self.conv1(x)
        img = self.conv2(x) + x_img
        x2 = torch.sigmoid(self.conv3(img))
        x1 = x1 * x2
        x1 = x1 + x
        return x1, img

##########################################################################
## Spatial Attention
class SALayer(nn.Module):
    def __init__(self, kernel_size=7):
        super(SALayer, self).__init__()
        self.conv1 = nn.Conv2d(2, 1, kernel_size, padding=kernel_size // 2, bias=False)
        self.sigmoid = nn.Sigmoid()

    def forward(self, x):
        avg_out = torch.mean(x, dim=1, keepdim=True)
        max_out, _ = torch.max(x, dim=1, keepdim=True)
        y = torch.cat([avg_out, max_out], dim=1)
        y = self.conv1(y)
        y = self.sigmoid(y)
        return x * y

# Spatial Attention Block (SAB)
class SAB(nn.Module):
    def __init__(self, n_feat, kernel_size, reduction, bias, act):
        super(SAB, self).__init__()
        modules_body = [conv(n_feat, n_feat, kernel_size, bias=bias), act, conv(n_feat, n_feat, kernel_size, bias=bias)]
        self.body = nn.Sequential(*modules_body)
        self.SA = SALayer(kernel_size=7)

    def forward(self, x):
        res = self.body(x)
        res = self.SA(res)
        res += x
        return res

##########################################################################
## Pixel Attention
class PALayer(nn.Module):
    def __init__(self, channel, reduction=16, bias=False):
        super(PALayer, self).__init__()
        self.pa = nn.Sequential(
            nn.Conv2d(channel, channel // reduction, 1, padding=0, bias=bias),
            nn.ReLU(inplace=True),
            nn.Conv2d(channel // reduction, channel, 1, padding=0, bias=bias), # channel <-> 1
            nn.Sigmoid()
        )

    def forward(self, x):
        y = self.pa(x)
        return x * y

## Pixel Attention Block (PAB)
class PAB(nn.Module):
    def __init__(self, n_feat, kernel_size, reduction, bias, act):
        super(PAB, self).__init__()
        modules_body = [conv(n_feat, n_feat, kernel_size, bias=bias), act, conv(n_feat, n_feat, kernel_size, bias=bias)]
        self.PA = PALayer(n_feat, reduction, bias=bias)
        self.body = nn.Sequential(*modules_body)

    def forward(self, x):
        res = self.body(x)
        res = self.PA(res)
        res += x
        return res

##########################################################################
## Channel Attention Layer
class CALayer(nn.Module):
    def __init__(self, channel, reduction=16, bias=False):
        super(CALayer, self).__init__()
        # global average pooling: feature --> point
        self.avg_pool = nn.AdaptiveAvgPool2d(1)
        # feature channel downscale and upscale --> channel weight
        self.conv_du = nn.Sequential(
            nn.Conv2d(channel, channel // reduction, 1, padding=0, bias=bias),
            nn.ReLU(inplace=True),
            nn.Conv2d(channel // reduction, channel, 1, padding=0, bias=bias),
            nn.Sigmoid()
        )

    def forward(self, x):
        y = self.avg_pool(x)
        y = self.conv_du(y)
        return x * y

## Channel Attention Block (CAB)
class CAB(nn.Module):
    def __init__(self, n_feat, kernel_size, reduction, bias, act):
        super(CAB, self).__init__()
        modules_body = [conv(n_feat, n_feat, kernel_size, bias=bias), act, conv(n_feat, n_feat, kernel_size, bias=bias)]

        self.CA = CALayer(n_feat, reduction, bias=bias)
        self.body = nn.Sequential(*modules_body)

    def forward(self, x):
        res = self.body(x)
        res = self.CA(res)
        res += x
        return res，模型是：# 将 4输入分开，构建新的相同模态结合的2输入，2分支
import math
import logging
from functools import partial
from collections import OrderedDict
from copy import deepcopy

import torch
import torch.nn as nn
import torch.nn.functional as F

from timm.models.layers import to_2tuple

from lib.models.layers.patch_embed import PatchEmbed, PatchEmbed_event, xcorr_depthwise
from .utils import combine_tokens, recover_tokens
from .vit import VisionTransformer
from ..layers.attn_blocks import CEBlock
from .ad_counter_guide import Counter_Guide_Enhanced
_logger = logging.getLogger(__name__)
                            

class VisionTransformerCE(VisionTransformer):
    """ Vision Transformer with candidate elimination (CE) module

    A PyTorch impl of : `An Image is Worth 16x16 Words: Transformers for Image Recognition at Scale`
        - https://arxiv.org/abs/2010.11929

    Includes distillation token & head support for `DeiT: Data-efficient Image Transformers`
        - https://arxiv.org/abs/2012.12877
    """
    def __init__(self, img_size=224, patch_size=16, in_chans=3, num_classes=1000, embed_dim=768, depth=12,
                 num_heads=12, mlp_ratio=4., qkv_bias=True, representation_size=None, distilled=False,
                 drop_rate=0., attn_drop_rate=0., drop_path_rate=0., embed_layer=PatchEmbed, norm_layer=None,
                 act_layer=None, weight_init='',
                 ce_loc=None, ce_keep_ratio=None):
        super().__init__()
        if isinstance(img_size, tuple):
            self.img_size = img_size
        else:
            self.img_size = to_2tuple(img_size)
        self.patch_size = patch_size
        self.in_chans = in_chans

        self.num_classes = num_classes
        self.num_features = self.embed_dim = embed_dim  # num_features for consistency with other models
        self.num_tokens = 2 if distilled else 1
        norm_layer = norm_layer or partial(nn.LayerNorm, eps=1e-6)
        act_layer = act_layer or nn.GELU

        self.patch_embed = embed_layer(
            img_size=img_size, patch_size=patch_size, in_chans=in_chans, embed_dim=embed_dim)
        num_patches = self.patch_embed.num_patches

        self.cls_token = nn.Parameter(torch.zeros(1, 1, embed_dim))
        self.dist_token = nn.Parameter(torch.zeros(1, 1, embed_dim)) if distilled else None
        self.pos_embed = nn.Parameter(torch.zeros(1, num_patches + self.num_tokens, embed_dim))
        self.pos_drop = nn.Dropout(p=drop_rate)
        self.pos_embed_event = PatchEmbed_event(in_chans=32, embed_dim=768, kernel_size=4, stride=4)
        dpr = [x.item() for x in torch.linspace(0, drop_path_rate, depth)]  # stochastic depth decay rule
        blocks = []
        ce_index = 0
        self.ce_loc = ce_loc
        for i in range(depth):
            ce_keep_ratio_i = 1.0
            if ce_loc is not None and i in ce_loc:
                ce_keep_ratio_i = ce_keep_ratio[ce_index]
                ce_index += 1

            blocks.append(
                CEBlock(
                    dim=embed_dim, num_heads=num_heads, mlp_ratio=mlp_ratio, qkv_bias=qkv_bias, drop=drop_rate,
                    attn_drop=attn_drop_rate, drop_path=dpr[i], norm_layer=norm_layer, act_layer=act_layer,
                    keep_ratio_search=ce_keep_ratio_i)
            )

        self.blocks = nn.Sequential(*blocks)
        self.norm = norm_layer(embed_dim)

        self.init_weights(weight_init)
    
        # 添加交互模块counter_guide
        self.counter_guide = Counter_Guide_Enhanced(768, 768)
    
    def forward_features(self, z, x, event_z, event_x,
                         mask_z=None, mask_x=None,
                         ce_template_mask=None, ce_keep_rate=None,
                         return_last_attn=False
                         ):
        # 分支1 处理流程
        B, H, W = x.shape[0], x.shape[2], x.shape[3]

        x = self.patch_embed(x)
        z = self.patch_embed(z)
        z += self.pos_embed_z
        x += self.pos_embed_x        

        if mask_z is not None and mask_x is not None:
            mask_z = F.interpolate(mask_z[None].float(), scale_factor=1. / self.patch_size).to(torch.bool)[0]
            mask_z = mask_z.flatten(1).unsqueeze(-1)

            mask_x = F.interpolate(mask_x[None].float(), scale_factor=1. / self.patch_size).to(torch.bool)[0]
            mask_x = mask_x.flatten(1).unsqueeze(-1)

            mask_x = combine_tokens(mask_z, mask_x, mode=self.cat_mode)
            mask_x = mask_x.squeeze(-1)

        if self.add_cls_token:
            cls_tokens = self.cls_token.expand(B, -1, -1)
            cls_tokens = cls_tokens + self.cls_pos_embed
        if self.add_sep_seg:
            x += self.search_segment_pos_embed
            z += self.template_segment_pos_embed
        x = combine_tokens(z, x, mode=self.cat_mode)
        if self.add_cls_token:
            x = torch.cat([cls_tokens, x], dim=1)
        x = self.pos_drop(x)

        lens_z = self.pos_embed_z.shape[1]
        lens_x = self.pos_embed_x.shape[1]
        global_index_t = torch.linspace(0, lens_z - 1, lens_z).to(x.device)
        global_index_t = global_index_t.repeat(B, 1)
        global_index_s = torch.linspace(0, lens_x - 1, lens_x).to(x.device)
        global_index_s = global_index_s.repeat(B, 1)
        removed_indexes_s = []
        # # 分支2 处理流程
        event_x = self.pos_embed_event(event_x)
        event_z = self.pos_embed_event(event_z)
        event_x += self.pos_embed_x
        event_z += self.pos_embed_z

        event_x = combine_tokens(event_z, event_x, mode=self.cat_mode)

        if self.add_cls_token:
            event_x = torch.cat([cls_tokens, event_x], dim=1)

        lens_z = self.pos_embed_z.shape[1]
        lens_x = self.pos_embed_x.shape[1]

        global_index_t1 = torch.linspace(0, lens_z - 1, lens_z).to(event_x.device)
        global_index_t1 = global_index_t1.repeat(B, 1)
        global_index_s1 = torch.linspace(0, lens_x - 1, lens_x).to(event_x.device)
        global_index_s1 = global_index_s1.repeat(B, 1)

        removed_indexes_s1 = []

        for i, blk in enumerate(self.blocks):
            # 第一个分支处理
            x, global_index_t, global_index_s, removed_index_s, attn = \
                blk(x, global_index_t, global_index_s, mask_x, ce_template_mask, ce_keep_rate)
            # 第二个分支处理
            event_x, global_index_t1, global_index_s1, removed_index_s1, attn1 = \
                blk(event_x, global_index_t1, global_index_s1, mask_x, ce_template_mask, ce_keep_rate)


            if self.ce_loc is not None and i in self.ce_loc:
                removed_indexes_s.append(removed_index_s)
                removed_indexes_s1.append(removed_index_s1)

            # 在第1层增加counter_guide模块,验证早期融合效果
            if i == 0 :
                # 新增原始特征（在counter_guide之前的特征，便于后续的loss计算）
                A_original_x = x.clone() # 保存原始x特征 （RGB）
                A_original_event_x = event_x.clone() # 保存原始event特征 （event）

                # 引入counter_guide进行特征增强
                enhanced_x, enhanced_event_x = self.counter_guide(x, event_x)

                # 保存经过counter_guide增强的特征
                A_enhanced_x = enhanced_x  # 保存增强后的特征
                A_enhanced_event_x = enhanced_event_x  # 保存增强后的特征
                # 将增强后的特征与原特征相加
                x = x + enhanced_x
                event_x = event_x + enhanced_event_x
        
        # 恢复特征tokens ###############
        if removed_indexes_s and removed_indexes_s[0] is not None:
            removed_indexes_cat = torch.cat(removed_indexes_s, dim=1)
            pruned_lens_x = lens_x - global_index_s.shape[1]
            pad_x = torch.zeros([B, pruned_lens_x, x.shape[2]], device=x.device)
            x = torch.cat([x, pad_x], dim=1)
            index_all = torch.cat([global_index_s, removed_indexes_cat], dim=1)
            C = x.shape[-1]
            x = torch.zeros_like(x).scatter(dim=1, index=index_all.unsqueeze(-1).expand(B, -1, C).to(torch.int64), src=x)
        
        x = recover_tokens(x, global_index_t.shape[1], lens_x, mode=self.cat_mode)
        
        
        if removed_indexes_s1 and removed_indexes_s1[0] is not None:
            removed_indexes_cat1 = torch.cat(removed_indexes_s1, dim=1)
            pruned_lens_x1 = lens_x - global_index_s1.shape[1]
            pad_x1 = torch.zeros([B, pruned_lens_x1, event_x.shape[2]], device=event_x.device)
            event_x = torch.cat([event_x, pad_x1], dim=1)
            index_all1 = torch.cat([global_index_s1, removed_indexes_cat1], dim=1)
            C = event_x.shape[-1]
            event_x = torch.zeros_like(event_x).scatter_(dim=1, index=index_all1.unsqueeze(-1).expand(B, -1, C).to(torch.int64), src=event_x)
        
        event_x = recover_tokens(event_x, global_index_t1.shape[1], lens_x, mode=self.cat_mode)
        
        
        #################################
        
        
        # 应用LayerNorm归一化处理
        x = self.norm(x) 
        event_x = self.norm(event_x)

        x_cat = torch.cat([event_x,x], dim=1)
        x = x_cat
        aux_dict = {
            "attn": attn,
            'attn1': attn1,
            "removed_indexes_s": removed_indexes_s,  # used for visualization
            'removed_indexes_s1': removed_indexes_s1,
            # 在aux_dict中返回原始特征和增强特征
            'A_original_x': A_original_x,
            'A_original_event_x': A_original_event_x,
            'A_enhanced_x': A_enhanced_x,
            'A_enhanced_event_x': A_enhanced_event_x,
        }
        
        return x, aux_dict 

    def forward(self, z, x, event_z, event_x,
                ce_template_mask=None, ce_keep_rate=None,
                tnc_keep_rate=None,
                return_last_attn=False):

        x, aux_dict = self.forward_features(z, x, event_z, event_x, ce_template_mask=ce_template_mask, ce_keep_rate=ce_keep_rate,)

        return x, aux_dict


def _create_vision_transformer(pretrained=False, **kwargs):
    model = VisionTransformerCE(**kwargs)
    
    if pretrained:
        if 'npz' in pretrained:
            model.load_pretrained(pretrained, prefix='')
        else:
            checkpoint = torch.load(pretrained, map_location="cpu")
            missing_keys, unexpected_keys = model.load_state_dict(checkpoint["model"], strict=False)
            print('Load pretrained model from: ' + pretrained)

    return model


def vit_base_patch16_224_ce(pretrained=False, **kwargs):
    """ ViT-Base model (ViT-B/16) from original paper (https://arxiv.org/abs/2010.11929).
    """
    model_kwargs = dict(
        patch_size=16, embed_dim=768, depth=12, num_heads=12, **kwargs)
    model = _create_vision_transformer(pretrained=pretrained, **model_kwargs)
    return model


def vit_large_patch16_224_ce(pretrained=False, **kwargs):
    """ ViT-Large model (ViT-L/16) from original paper (https://arxiv.org/abs/2010.11929).
    """
    model_kwargs = dict(
        patch_size=16, embed_dim=1024, depth=24, num_heads=16, **kwargs)
    model = _create_vision_transformer(pretrained=pretrained, **model_kwargs)
    return model，那么分析不同的注意力模块，在vit_ce中如何集成，以及为什么集成在那里？