unik3d/layers/convnext.py

import torch
import torch.nn as nn


class CvnxtBlock(nn.Module):
    def __init__(
        self,
        dim,
        kernel_size=7,
        layer_scale=1.0,
        expansion=4,
        dilation=1,
        padding_mode: str = "zeros",
    ):
        super().__init__()
        self.dwconv = nn.Conv2d(
            dim,
            dim,
            kernel_size=kernel_size,
            padding=dilation * (kernel_size - 1) // 2,
            groups=dim,
            dilation=dilation,
            padding_mode=padding_mode,
        )  # depthwise conv
        self.norm = nn.LayerNorm(dim)
        self.pwconv1 = nn.Linear(dim, expansion * dim)
        self.act = nn.GELU()
        self.pwconv2 = nn.Linear(expansion * dim, dim)
        self.gamma = (
            nn.Parameter(layer_scale * torch.ones(1, dim, 1, 1))
            if layer_scale > 0.0
            else 1.0
        )
        self.skip_add = nn.quantized.FloatFunctional()

    def forward(self, x):
        input = x
        x = self.dwconv(x)
        x = x.permute(0, 2, 3, 1)  # (N, C, H, W) -> (N, H, W, C)
        x = self.norm(x)
        x = self.pwconv1(x)
        x = self.act(x)
        x = self.pwconv2(x)
        return self.skip_add.add(self.gamma * x.permute(0, 3, 1, 2), input)


class SimpleCvnxtBlock(nn.Module):
    def __init__(
        self,
        dim,
        output_dim=None,
        kernel_size=7,
        expansion=4,
        dilation=1,
        padding_mode: str = "zeros",
    ):
        super().__init__()
        output_dim = output_dim if output_dim is not None else dim
        self.dwconv = nn.Conv2d(
            dim,
            dim,
            kernel_size=kernel_size,
            padding=dilation * (kernel_size - 1) // 2,
            groups=dim,
            dilation=dilation,
            padding_mode=padding_mode,
        )  # depthwise conv
        self.norm = nn.LayerNorm(dim)
        self.pwconv1 = nn.Linear(dim, expansion * dim)
        self.act = nn.GELU()
        self.pwconv2 = nn.Linear(expansion * dim, output_dim)

    def forward(self, x):
        x = self.dwconv(x)
        x = x.permute(0, 2, 3, 1)  # (N, C, H, W) -> (N, H, W, C)
        x = self.norm(x)
        x = self.pwconv1(x)
        x = self.act(x)
        x = self.pwconv2(x)
        return x.permute(0, 3, 1, 2)  # (N, H, W, C) -> (N, C, H, W)