| import torch.nn as nn | |
| def _make_scratch(in_shape, out_shape, groups=1, expand=False): | |
| scratch = nn.Module() | |
| out_shape1 = out_shape | |
| out_shape2 = out_shape | |
| out_shape3 = out_shape | |
| if len(in_shape) >= 4: | |
| out_shape4 = out_shape | |
| if expand: | |
| out_shape1 = out_shape | |
| out_shape2 = out_shape * 2 | |
| out_shape3 = out_shape * 4 | |
| if len(in_shape) >= 4: | |
| out_shape4 = out_shape * 8 | |
| scratch.layer1_rn = nn.Conv2d(in_shape[0], out_shape1, kernel_size=3, stride=1, padding=1, bias=False, | |
| groups=groups) | |
| scratch.layer2_rn = nn.Conv2d(in_shape[1], out_shape2, kernel_size=3, stride=1, padding=1, bias=False, | |
| groups=groups) | |
| scratch.layer3_rn = nn.Conv2d(in_shape[2], out_shape3, kernel_size=3, stride=1, padding=1, bias=False, | |
| groups=groups) | |
| if len(in_shape) >= 4: | |
| scratch.layer4_rn = nn.Conv2d(in_shape[3], out_shape4, kernel_size=3, stride=1, padding=1, bias=False, | |
| groups=groups) | |
| return scratch | |
| class ResidualConvUnit(nn.Module): | |
| """Residual convolution module. | |
| """ | |
| def __init__(self, features, activation, bn): | |
| """Init. | |
| Args: | |
| features (int): number of features | |
| """ | |
| super().__init__() | |
| self.bn = bn | |
| self.groups = 1 | |
| self.conv1 = nn.Conv2d(features, features, kernel_size=3, stride=1, padding=1, bias=True, groups=self.groups) | |
| self.conv2 = nn.Conv2d(features, features, kernel_size=3, stride=1, padding=1, bias=True, groups=self.groups) | |
| if self.bn == True: | |
| self.bn1 = nn.BatchNorm2d(features) | |
| self.bn2 = nn.BatchNorm2d(features) | |
| self.activation = activation | |
| self.skip_add = nn.quantized.FloatFunctional() | |
| def forward(self, x): | |
| """Forward pass. | |
| Args: | |
| x (tensor): input | |
| Returns: | |
| tensor: output | |
| """ | |
| out = self.activation(x) | |
| out = self.conv1(out) | |
| if self.bn == True: | |
| out = self.bn1(out) | |
| out = self.activation(out) | |
| out = self.conv2(out) | |
| if self.bn == True: | |
| out = self.bn2(out) | |
| if self.groups > 1: | |
| out = self.conv_merge(out) | |
| return self.skip_add.add(out, x) | |
| class FeatureFusionBlock(nn.Module): | |
| """Feature fusion block. | |
| """ | |
| def __init__( | |
| self, | |
| features, | |
| activation, | |
| deconv=False, | |
| bn=False, | |
| expand=False, | |
| align_corners=True, | |
| size=None | |
| ): | |
| """Init. | |
| Args: | |
| features (int): number of features | |
| """ | |
| super(FeatureFusionBlock, self).__init__() | |
| self.deconv = deconv | |
| self.align_corners = align_corners | |
| self.groups = 1 | |
| self.expand = expand | |
| out_features = features | |
| if self.expand == True: | |
| out_features = features // 2 | |
| self.out_conv = nn.Conv2d(features, out_features, kernel_size=1, stride=1, padding=0, bias=True, groups=1) | |
| self.resConfUnit1 = ResidualConvUnit(features, activation, bn) | |
| self.resConfUnit2 = ResidualConvUnit(features, activation, bn) | |
| self.skip_add = nn.quantized.FloatFunctional() | |
| self.size = size | |
| def forward(self, *xs, size=None): | |
| """Forward pass. | |
| Returns: | |
| tensor: output | |
| """ | |
| output = xs[0] | |
| if len(xs) == 2: | |
| res = self.resConfUnit1(xs[1]) | |
| output = self.skip_add.add(output, res) | |
| output = self.resConfUnit2(output) | |
| if (size is None) and (self.size is None): | |
| modifier = {"scale_factor": 2} | |
| elif size is None: | |
| modifier = {"size": self.size} | |
| else: | |
| modifier = {"size": size} | |
| output = nn.functional.interpolate(output, **modifier, mode="bilinear", align_corners=self.align_corners) | |
| output = self.out_conv(output) | |
| return output | |