tmp.py

"""Adapted from https://github.com/milesial/Pytorch-UNet/tree/master/unet"""
import torch
import torch.nn as nn
import torch.nn.functional as F


class UNet(nn.Module):
    def __init__(self, n_channels, n_classes, channels=(32, 64, 128, 256, 512), bilinear=True):
        super(UNet, self).__init__()
        self.n_channels = n_channels
        self.n_classes = n_classes
        self.channels = channels
        self.bilinear = bilinear

        self.inc = DoubleConv(n_channels, channels[0])
        self.down1 = Down(channels[0], channels[1])
        self.down2 = Down(channels[1], channels[2])
        self.down3 = Down(channels[2], channels[3])
        factor = 2 if bilinear else 1
        self.down4 = Down(channels[3], channels[4] // factor)
        self.up1 = Up(channels[4], channels[3] // factor, bilinear)
        self.up2 = Up(channels[3], channels[2] // factor, bilinear)
        self.up3 = Up(channels[2], channels[1] // factor, bilinear)
        self.up4 = Up(channels[1], channels[0], bilinear)
        self.outc = OutConv(channels[0], n_classes)

    def forward(self, x):
        x1 = self.inc(x)
        x2 = self.down1(x1)
        x3 = self.down2(x2)
        x4 = self.down3(x3)
        x5 = self.down4(x4)
        x = self.up1(x5, x4)
        x = self.up2(x, x3)
        x = self.up3(x, x2)
        x = self.up4(x, x1)
        logits = self.outc(x)
        return logits


class DoubleConv(nn.Module):
    """(convolution => [BN] => ReLU) * 2"""

    def __init__(self, in_channels, out_channels, mid_channels=None):
        super().__init__()
        if not mid_channels:
            mid_channels = out_channels
        self.double_conv = nn.Sequential(
            nn.Conv3d(in_channels, mid_channels, kernel_size=3, padding=1),
            nn.BatchNorm3d(mid_channels),
            nn.ReLU(inplace=True),
            nn.Conv3d(mid_channels, out_channels, kernel_size=3, padding=1),
            nn.BatchNorm3d(out_channels),
            nn.ReLU(inplace=True)
        )

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


class Down(nn.Module):
    """Downscaling with maxpool then double conv"""

    def __init__(self, in_channels, out_channels):
        super().__init__()
        self.maxpool_conv = nn.Sequential(
            nn.MaxPool3d(2),
            DoubleConv(in_channels, out_channels)
        )

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


class Up(nn.Module):
    """Upscaling then double conv"""

    def __init__(self, in_channels, out_channels, bilinear=True):
        super().__init__()

        # if bilinear, use the normal convolutions to reduce the number of channels
        if bilinear:
            self.up = nn.Upsample(scale_factor=2, mode='trilinear', align_corners=True)
            self.conv = DoubleConv(in_channels, out_channels, in_channels // 2)
        else:
            self.up = nn.ConvTranspose3d(in_channels , in_channels // 2, kernel_size=2, stride=2)
            self.conv = DoubleConv(in_channels, out_channels)


    def forward(self, x1, x2):
        x1 = self.up(x1)
        # input is CHW
        diffY = x2.size()[2] - x1.size()[2]
        diffX = x2.size()[3] - x1.size()[3]

        x1 = F.pad(x1, [diffX // 2, diffX - diffX // 2,
                        diffY // 2, diffY - diffY // 2])
        # if you have padding issues, see
        # https://github.com/HaiyongJiang/U-Net-Pytorch-Unstructured-Buggy/commit/0e854509c2cea854e247a9c615f175f76fbb2e3a
        # https://github.com/xiaopeng-liao/Pytorch-UNet/commit/8ebac70e633bac59fc22bb5195e513d5832fb3bd
        x = torch.cat([x2, x1], dim=1)
        return self.conv(x)


class OutConv(nn.Module):
    def __init__(self, in_channels, out_channels):
        super(OutConv, self).__init__()
        self.conv = nn.Conv3d(in_channels, out_channels, kernel_size=1)

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


if __name__ == "__main__":
    def get_n_params(model):
        pp = 0
        for p in list(model.parameters()):
            nn = 1
            for s in list(p.size()):
                nn = nn * s
            pp += nn
        return pp

    net = UNet(1, 3)
    net = net.eval()
    print(get_n_params(net))

    # gpu
    net = net.cuda()
    import time
    for _ in range(10):
        start = time.time()
        x = torch.zeros((1, 1, 32, 256, 256)).cuda()
        with torch.no_grad():
            y = net(x)
        print(f'Time: {time.time() - start}')

    # cpu
    net = net.cpu().eval()
    import time
    for _ in range(10):
        start = time.time()
        x = torch.zeros((1, 1, 32, 256, 256))
        with torch.no_grad():
            y = net(x)
        print(f'Time: {time.time() - start}')