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| # Copyright (c) Facebook, Inc. and its affiliates. | |
| # https://github.com/facebookresearch/detectron2/blob/main/projects/TridentNet/tridentnet/trident_conv.py | |
| import torch | |
| from torch import nn | |
| from torch.nn import functional as F | |
| from torch.nn.modules.utils import _pair | |
| class MultiScaleTridentConv(nn.Module): | |
| def __init__( | |
| self, | |
| in_channels, | |
| out_channels, | |
| kernel_size, | |
| stride=1, | |
| strides=1, | |
| paddings=0, | |
| dilations=1, | |
| dilation=1, | |
| groups=1, | |
| num_branch=1, | |
| test_branch_idx=-1, | |
| bias=False, | |
| norm=None, | |
| activation=None, | |
| ): | |
| super(MultiScaleTridentConv, self).__init__() | |
| self.in_channels = in_channels | |
| self.out_channels = out_channels | |
| self.kernel_size = _pair(kernel_size) | |
| self.num_branch = num_branch | |
| self.stride = _pair(stride) | |
| self.groups = groups | |
| self.with_bias = bias | |
| self.dilation = dilation | |
| if isinstance(paddings, int): | |
| paddings = [paddings] * self.num_branch | |
| if isinstance(dilations, int): | |
| dilations = [dilations] * self.num_branch | |
| if isinstance(strides, int): | |
| strides = [strides] * self.num_branch | |
| self.paddings = [_pair(padding) for padding in paddings] | |
| self.dilations = [_pair(dilation) for dilation in dilations] | |
| self.strides = [_pair(stride) for stride in strides] | |
| self.test_branch_idx = test_branch_idx | |
| self.norm = norm | |
| self.activation = activation | |
| assert len({self.num_branch, len(self.paddings), len(self.strides)}) == 1 | |
| self.weight = nn.Parameter( | |
| torch.Tensor(out_channels, in_channels // groups, *self.kernel_size) | |
| ) | |
| if bias: | |
| self.bias = nn.Parameter(torch.Tensor(out_channels)) | |
| else: | |
| self.bias = None | |
| nn.init.kaiming_uniform_(self.weight, nonlinearity="relu") | |
| if self.bias is not None: | |
| nn.init.constant_(self.bias, 0) | |
| def forward(self, inputs): | |
| num_branch = self.num_branch if self.training or self.test_branch_idx == -1 else 1 | |
| assert len(inputs) == num_branch | |
| if self.training or self.test_branch_idx == -1: | |
| outputs = [ | |
| F.conv2d(input, self.weight, self.bias, stride, padding, self.dilation, self.groups) | |
| for input, stride, padding in zip(inputs, self.strides, self.paddings) | |
| ] | |
| else: | |
| outputs = [ | |
| F.conv2d( | |
| inputs[0], | |
| self.weight, | |
| self.bias, | |
| self.strides[self.test_branch_idx] if self.test_branch_idx == -1 else self.strides[-1], | |
| self.paddings[self.test_branch_idx] if self.test_branch_idx == -1 else self.paddings[-1], | |
| self.dilation, | |
| self.groups, | |
| ) | |
| ] | |
| if self.norm is not None: | |
| outputs = [self.norm(x) for x in outputs] | |
| if self.activation is not None: | |
| outputs = [self.activation(x) for x in outputs] | |
| return outputs | |