model.py

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


class Attention(nn.Module):
    def __init__(self, in_planes, out_planes, kernel_size, groups=1, reduction=0.0625, kernel_num=4, min_channel=16):
        super(Attention, self).__init__()
        attention_channel = max(int(in_planes * reduction), min_channel)
        self.kernel_size = kernel_size
        self.kernel_num = kernel_num
        self.temperature = 1.0

        self.avgpool = nn.AdaptiveAvgPool2d(1)
        self.fc = nn.Conv2d(in_planes, attention_channel, 1, bias=False)
        self.bn = nn.BatchNorm2d(attention_channel)
        self.relu = nn.ReLU(inplace=True)

        self.channel_fc = nn.Conv2d(attention_channel, in_planes, 1, bias=True)
        self.func_channel = self.get_channel_attention

        if in_planes == groups and in_planes == out_planes:  # depth-wise convolution
            self.func_filter = self.skip
        else:
            self.filter_fc = nn.Conv2d(attention_channel, out_planes, 1, bias=True)
            self.func_filter = self.get_filter_attention

        if kernel_size == 1:  # point-wise convolution
            self.func_spatial = self.skip
        else:
            self.spatial_fc = nn.Conv2d(attention_channel, kernel_size * kernel_size, 1, bias=True)
            self.func_spatial = self.get_spatial_attention

        if kernel_num == 1:
            self.func_kernel = self.skip
        else:
            self.kernel_fc = nn.Conv2d(attention_channel, kernel_num, 1, bias=True)
            self.func_kernel = self.get_kernel_attention

        self._initialize_weights()

    def _initialize_weights(self):
        for m in self.modules():
            if isinstance(m, nn.Conv2d):
                nn.init.kaiming_normal_(m.weight, mode='fan_out', nonlinearity='relu')
                if m.bias is not None:
                    nn.init.constant_(m.bias, 0)
            if isinstance(m, nn.BatchNorm2d):
                nn.init.constant_(m.weight, 1)
                nn.init.constant_(m.bias, 0)

    def update_temperature(self, temperature):
        self.temperature = temperature

    @staticmethod
    def skip(_):
        return 1.0

    def get_channel_attention(self, x):
        channel_attention = torch.sigmoid(self.channel_fc(x).view(x.size(0), -1, 1, 1) / self.temperature)
        return channel_attention

    def get_filter_attention(self, x):
        filter_attention = torch.sigmoid(self.filter_fc(x).view(x.size(0), -1, 1, 1) / self.temperature)
        return filter_attention

    def get_spatial_attention(self, x):
        spatial_attention = self.spatial_fc(x).view(x.size(0), 1, 1, 1, self.kernel_size, self.kernel_size)
        spatial_attention = torch.sigmoid(spatial_attention / self.temperature)
        return spatial_attention

    def get_kernel_attention(self, x):
        kernel_attention = self.kernel_fc(x).view(x.size(0), -1, 1, 1, 1, 1)
        kernel_attention = F.softmax(kernel_attention / self.temperature, dim=1)
        return kernel_attention

    def forward(self, x):
        x = self.avgpool(x)
        x = self.fc(x)
        x = self.bn(x)
        x = self.relu(x)
        return self.func_channel(x), self.func_filter(x), self.func_spatial(x), self.func_kernel(x)


class ODConv2d(nn.Module):
    def __init__(self, in_planes, out_planes, kernel_size, stride=1, padding=0, dilation=1, groups=1,
                 reduction=0.0625, kernel_num=4):
        super(ODConv2d, self).__init__()
        self.in_planes = in_planes
        self.out_planes = out_planes
        self.kernel_size = kernel_size
        self.stride = stride
        self.padding = padding
        self.dilation = dilation
        self.groups = groups
        self.kernel_num = kernel_num
        self.attention = Attention(in_planes, out_planes, kernel_size, groups=groups,
                                   reduction=reduction, kernel_num=kernel_num)
        self.weight = nn.Parameter(torch.randn(kernel_num, out_planes, in_planes//groups, kernel_size, kernel_size),
                                   requires_grad=True)
        self._initialize_weights()

        if self.kernel_size == 1 and self.kernel_num == 1:
            self._forward_impl = self._forward_impl_pw1x
        else:
            self._forward_impl = self._forward_impl_common

    def _initialize_weights(self):
        for i in range(self.kernel_num):
            nn.init.kaiming_normal_(self.weight[i], mode='fan_out', nonlinearity='relu')

    def update_temperature(self, temperature):
        self.attention.update_temperature(temperature)

    def _forward_impl_common(self, x):
        # Multiplying channel attention (or filter attention) to weights and feature maps are equivalent,
        # while we observe that when using the latter method the models will run faster with less gpu memory cost.
        channel_attention, filter_attention, spatial_attention, kernel_attention = self.attention(x)
        batch_size, in_planes, height, width = x.size()
        x = x * channel_attention
        x = x.reshape(1, -1, height, width)
        aggregate_weight = spatial_attention * kernel_attention * self.weight.unsqueeze(dim=0)
        aggregate_weight = torch.sum(aggregate_weight, dim=1).view(
            [-1, self.in_planes // self.groups, self.kernel_size, self.kernel_size])
        output = F.conv2d(x, weight=aggregate_weight, bias=None, stride=self.stride, padding=self.padding,
                          dilation=self.dilation, groups=self.groups * batch_size)
        output = output.view(batch_size, self.out_planes, output.size(-2), output.size(-1))
        output = output * filter_attention
        return output

    def _forward_impl_pw1x(self, x):
        channel_attention, filter_attention, spatial_attention, kernel_attention = self.attention(x)
        x = x * channel_attention
        output = F.conv2d(x, weight=self.weight.squeeze(dim=0), bias=None, stride=self.stride, padding=self.padding,
                          dilation=self.dilation, groups=self.groups)
        output = output * filter_attention
        return output

    def forward(self, x):
        return self._forward_impl(x)


class BasicConv(nn.Module):
    def __init__(self, in_planes, out_planes, kernel_size, stride=1, padding=0, dilation=1, groups=1, relu=True, bn=True, bias=False):
        super(BasicConv, self).__init__()
        self.out_channels = out_planes
        self.conv = ODConv2d(in_planes, out_planes, kernel_size=kernel_size, stride=stride, padding=padding, dilation=dilation, groups=groups)
        self.bn = nn.BatchNorm2d(out_planes,eps=1e-5, momentum=0.01, affine=True) if bn else None
        self.relu = nn.ReLU() if relu else None

    def forward(self, x):
        x = self.conv(x)
        if self.bn is not None:
            x = self.bn(x)
        if self.relu is not None:
            x = self.relu(x)
        return x

class Flatten(nn.Module):
    def forward(self, x):
        return x.view(x.size(0), -1)

class ChannelGate(nn.Module):
    def __init__(self, gate_channels, reduction_ratio=16, pool_types=['avg', 'max']):
        super(ChannelGate, self).__init__()
        self.gate_channels = gate_channels
        self.mlp = nn.Sequential(
            Flatten(),
            nn.Linear(gate_channels, gate_channels // reduction_ratio),
            nn.ReLU(),
            nn.Linear(gate_channels // reduction_ratio, gate_channels)
            )
        self.pool_types = pool_types
    def forward(self, x):
        channel_att_sum = None
        for pool_type in self.pool_types:
            if pool_type=='avg':
                avg_pool = F.avg_pool2d( x, (x.size(2), x.size(3)), stride=(x.size(2), x.size(3)))
                channel_att_raw = self.mlp( avg_pool )
            elif pool_type=='max':
                max_pool = F.max_pool2d( x, (x.size(2), x.size(3)), stride=(x.size(2), x.size(3)))
                channel_att_raw = self.mlp( max_pool )
            elif pool_type=='lp':
                lp_pool = F.lp_pool2d( x, 2, (x.size(2), x.size(3)), stride=(x.size(2), x.size(3)))
                channel_att_raw = self.mlp( lp_pool )
            elif pool_type=='lse':
                # LSE pool only
                lse_pool = logsumexp_2d(x)
                channel_att_raw = self.mlp( lse_pool )

            if channel_att_sum is None:
                channel_att_sum = channel_att_raw
            else:
                channel_att_sum = channel_att_sum + channel_att_raw

        scale = torch.sigmoid( channel_att_sum ).unsqueeze(2).unsqueeze(3).expand_as(x)
        return x * scale

def logsumexp_2d(tensor):
    tensor_flatten = tensor.view(tensor.size(0), tensor.size(1), -1)
    s, _ = torch.max(tensor_flatten, dim=2, keepdim=True)
    outputs = s + (tensor_flatten - s).exp().sum(dim=2, keepdim=True).log()
    return outputs

class ChannelPool(nn.Module):
    def forward(self, x):
        return torch.cat( (torch.max(x,1)[0].unsqueeze(1), torch.mean(x,1).unsqueeze(1)), dim=1 )

class SpatialGate(nn.Module):
    def __init__(self):
        super(SpatialGate, self).__init__()
        kernel_size = 7
        self.compress = ChannelPool()
        self.spatial = ODConv2d(2, 1, kernel_size, stride=1, padding=(kernel_size-1) // 2)
    def forward(self, x):
        x_compress = self.compress(x)
        x_out = self.spatial(x_compress)
        scale = torch.sigmoid(x_out) # broadcasting
        return x * scale

class CBAM(nn.Module):
    def __init__(self, gate_channels, reduction_ratio=16, pool_types=['avg', 'max'], no_spatial=False):
        super(CBAM, self).__init__()
        self.ChannelGate = ChannelGate(gate_channels, reduction_ratio, pool_types)
        self.no_spatial=no_spatial
        if not no_spatial:
            self.SpatialGate = SpatialGate()
    def forward(self, x):
        x_out = self.ChannelGate(x)
        if not self.no_spatial:
            x_out = self.SpatialGate(x_out)
        return x_out


class Dual(nn.Module):

    def __init__(self):
        super(Dual, self).__init__()

        self.feature_extractor2 = nn.Sequential(

            nn.Conv2d(1,64,3,1,1),
            nn.BatchNorm2d(64),
            nn.ReLU(),
            nn.MaxPool2d((2,2),(2,2)),

            nn.Conv2d(64,64,3,1,1),
            nn.BatchNorm2d(64),
            nn.ReLU(),
            nn.MaxPool2d((4,4),(4,4)),

            nn.Conv2d(64,128,3,1,1),
            nn.BatchNorm2d(128),
            nn.ReLU(),
            nn.MaxPool2d((4,4),(4,4)),

            nn.Conv2d(128,128,3,1,1),
            nn.BatchNorm2d(128),
            nn.ReLU(),
            nn.MaxPool2d((4,4),(4,4))
        )

        self.cbam = CBAM(128)

        self.gru = nn.GRU(
            input_size=128,
            hidden_size=256,
            batch_first=True
        )

        self.fc2 = nn.Sequential(
            nn.Flatten(),
            nn.Linear(256,512),
            nn.ReLU(),
            nn.Linear(512,5)
        )

        self.fc3 = nn.Linear(5,5)

    def forward(self, mfcc):

        x = self.feature_extractor2(mfcc)
        x = self.cbam(x)

        if x.dim() != 4:
            raise ValueError(f"Invalid shape after CNN: {x.shape}")

        # (B,128,1,1) -> (B,128)
        x = x.squeeze(-1).squeeze(-1)

        # -> (B,1,128)
        x = x.unsqueeze(1)

        x, _ = self.gru(x)

        x = self.fc2(x)
        x = self.fc3(x)

        return x