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Source code for mmedit.models.components.discriminators.multi_layer_disc

# Copyright (c) OpenMMLab. All rights reserved.
import torch.nn as nn
from mmcv.cnn import ConvModule
from mmcv.runner import load_checkpoint

from mmedit.models.common import LinearModule
from mmedit.models.registry import COMPONENTS
from mmedit.utils import get_root_logger


[docs]@COMPONENTS.register_module() class MultiLayerDiscriminator(nn.Module): """Multilayer Discriminator. This is a commonly used structure with stacked multiply convolution layers. Args: in_channels (int): Input channel of the first input convolution. max_channels (int): The maximum channel number in this structure. num_conv (int): Number of stacked intermediate convs (including input conv but excluding output conv). fc_in_channels (int | None): Input dimension of the fully connected layer. If `fc_in_channels` is None, the fully connected layer will be removed. fc_out_channels (int): Output dimension of the fully connected layer. kernel_size (int): Kernel size of the conv modules. Default to 5. conv_cfg (dict): Config dict to build conv layer. norm_cfg (dict): Config dict to build norm layer. act_cfg (dict): Config dict for activation layer, "relu" by default. out_act_cfg (dict): Config dict for output activation, "relu" by default. with_input_norm (bool): Whether add normalization after the input conv. Default to True. with_out_convs (bool): Whether add output convs to the discriminator. The output convs contain two convs. The first out conv has the same setting as the intermediate convs but a stride of 1 instead of 2. The second out conv is a conv similar to the first out conv but reduces the number of channels to 1 and has no activation layer. Default to False. with_spectral_norm (bool): Whether use spectral norm after the conv layers. Default to False. kwargs (keyword arguments). """ def __init__(self, in_channels, max_channels, num_convs=5, fc_in_channels=None, fc_out_channels=1024, kernel_size=5, conv_cfg=None, norm_cfg=None, act_cfg=dict(type='ReLU'), out_act_cfg=dict(type='ReLU'), with_input_norm=True, with_out_convs=False, with_spectral_norm=False, **kwargs): super().__init__() if fc_in_channels is not None: assert fc_in_channels > 0 self.max_channels = max_channels self.with_fc = fc_in_channels is not None self.num_convs = num_convs self.with_out_act = out_act_cfg is not None self.with_out_convs = with_out_convs cur_channels = in_channels for i in range(num_convs): out_ch = min(64 * 2**i, max_channels) norm_cfg_ = norm_cfg act_cfg_ = act_cfg if i == 0 and not with_input_norm: norm_cfg_ = None elif (i == num_convs - 1 and not self.with_fc and not self.with_out_convs): norm_cfg_ = None act_cfg_ = out_act_cfg self.add_module( f'conv{i + 1}', ConvModule( cur_channels, out_ch, kernel_size=kernel_size, stride=2, padding=kernel_size // 2, norm_cfg=norm_cfg_, act_cfg=act_cfg_, with_spectral_norm=with_spectral_norm, **kwargs)) cur_channels = out_ch if self.with_out_convs: cur_channels = min(64 * 2**(num_convs - 1), max_channels) out_ch = min(64 * 2**num_convs, max_channels) self.add_module( f'conv{num_convs + 1}', ConvModule( cur_channels, out_ch, kernel_size, stride=1, padding=kernel_size // 2, norm_cfg=norm_cfg, act_cfg=act_cfg, with_spectral_norm=with_spectral_norm, **kwargs)) self.add_module( f'conv{num_convs + 2}', ConvModule( out_ch, 1, kernel_size, stride=1, padding=kernel_size // 2, act_cfg=None, with_spectral_norm=with_spectral_norm, **kwargs)) if self.with_fc: self.fc = LinearModule( fc_in_channels, fc_out_channels, bias=True, act_cfg=out_act_cfg, with_spectral_norm=with_spectral_norm)
[docs] def forward(self, x): """Forward Function. Args: x (torch.Tensor): Input tensor with shape of (n, c, h, w). Returns: torch.Tensor: Output tensor with shape of (n, c, h', w') or (n, c). """ input_size = x.size() # out_convs has two additional ConvModules num_convs = self.num_convs + 2 * self.with_out_convs for i in range(num_convs): x = getattr(self, f'conv{i + 1}')(x) if self.with_fc: x = x.view(input_size[0], -1) x = self.fc(x) return x
[docs] def init_weights(self, pretrained=None): """Init weights for models. Args: pretrained (str, optional): Path for pretrained weights. If given None, pretrained weights will not be loaded. Defaults to None. """ if isinstance(pretrained, str): logger = get_root_logger() load_checkpoint(self, pretrained, strict=False, logger=logger) elif pretrained is None: for m in self.modules(): # Here, we only initialize the module with fc layer since the # conv and norm layers has been initialized in `ConvModule`. if isinstance(m, nn.Linear): nn.init.normal_(m.weight.data, 0.0, 0.02) nn.init.constant_(m.bias.data, 0.0) else: raise TypeError('pretrained must be a str or None')
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