YOLO-Tutorial-v2/yolo/models/yolov2/yolov2_basic.py

import torch
import torch.nn as nn
from typing import List


# --------------------- Basic modules ---------------------
def get_conv2d(c1, c2, k, p, s, d, g, bias=False):
    conv = nn.Conv2d(c1, c2, k, stride=s, padding=p, dilation=d, groups=g, bias=bias)

    return conv

def get_activation(act_type=None):
    if act_type == 'relu':
        return nn.ReLU(inplace=True)
    elif act_type == 'lrelu':
        return nn.LeakyReLU(0.1, inplace=True)
    elif act_type == 'mish':
        return nn.Mish(inplace=True)
    elif act_type == 'silu':
        return nn.SiLU(inplace=True)
    elif act_type is None:
        return nn.Identity()
    else:
        raise NotImplementedError
        
def get_norm(norm_type, dim):
    if norm_type == 'BN':
        return nn.BatchNorm2d(dim)
    elif norm_type == 'GN':
        return nn.GroupNorm(num_groups=32, num_channels=dim)
    elif norm_type is None:
        return nn.Identity()
    else:
        raise NotImplementedError

class BasicConv(nn.Module):
    def __init__(self, 
                 in_dim,                   # in channels
                 out_dim,                  # out channels 
                 kernel_size=1,            # kernel size 
                 padding=0,                # padding
                 stride=1,                 # padding
                 dilation=1,               # dilation
                 act_type  :str = 'lrelu', # activation
                 norm_type :str = 'BN',    # normalization
                 depthwise :bool = False
                ):
        super(BasicConv, self).__init__()
        self.depthwise = depthwise
        use_bias = False if norm_type is not None else True
        if not depthwise:
            self.conv = get_conv2d(in_dim, out_dim, k=kernel_size, p=padding, s=stride, d=dilation, g=1, bias=use_bias)
            self.norm = get_norm(norm_type, out_dim)
        else:
            self.conv1 = get_conv2d(in_dim, in_dim, k=kernel_size, p=padding, s=stride, d=dilation, g=in_dim, bias=use_bias)
            self.norm1 = get_norm(norm_type, in_dim)
            self.conv2 = get_conv2d(in_dim, out_dim, k=1, p=0, s=1, d=1, g=1)
            self.norm2 = get_norm(norm_type, out_dim)
        self.act  = get_activation(act_type)

    def forward(self, x):
        if not self.depthwise:
            return self.act(self.norm(self.conv(x)))
        else:
            # Depthwise conv
            x = self.norm1(self.conv1(x))
            # Pointwise conv
            x = self.act(self.norm2(self.conv2(x)))
            return x