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Source code for mmedit.models.editors.stylegan1.stylegan1

# Copyright (c) OpenMMLab. All rights reserved.
from typing import Dict, Optional, Tuple, Union

import torch
import torch.autograd as autograd
import torch.nn as nn
import torch.nn.functional as F
from mmengine import Config
from torch import Tensor

from mmedit.registry import MODELS
from ..pggan import ProgressiveGrowingGAN

[docs]ModelType = Union[Dict, nn.Module]
[docs]TrainInput = Union[dict, Tensor]
@MODELS.register_module('StyleGANV1') @MODELS.register_module('StyleGANv1') @MODELS.register_module()
[docs]class StyleGAN1(ProgressiveGrowingGAN): """Implementation of `A Style-Based Generator Architecture for Generative Adversarial Networks`. <https://openaccess.thecvf.com/content_CVPR_2019/html/Karras_A_Style-Based_Generator_Architecture_for_Generative_Adversarial_Networks_CVPR_2019_paper.html>`_ # noqa (StyleGANv1). This class is inheriant from :class:`~ProgressiveGrowingGAN` to support progressive training. Detailed architecture can be found in :class:`~mmedit.models.editors.stylegan1.StyleGAN1Generator` and :class:`~mmedit.models.editors.stylegan1.StyleGAN1Discriminator` Args: generator (ModelType): The config or model of the generator. discriminator (Optional[ModelType]): The config or model of the discriminator. Defaults to None. data_preprocessor (Optional[Union[dict, Config]]): The pre-process config or :class:`~mmedit.models.GenDataPreprocessor`. style_channels (int): The number of channels for style code. Defaults to 128. nkimgs_per_scale (dict): The number of images need for each resolution's training. Defaults to `{}`. intep_real (dict, optional): The config of interpolation method for real images. If not passed, bilinear interpolation with align_corners will be used. Defaults to None. transition_kimgs (int, optional): The number of images during used to transit from the previous torgb layer to newer torgb layer. Defaults to 600. prev_stage (int, optional): The resolution of previous stage. Used for resume training. Defaults to 0. ema_config (Optional[Dict]): The config for generator's exponential moving average setting. Defaults to None. """ def __init__(self, generator: ModelType, discriminator: Optional[ModelType] = None, data_preprocessor: Optional[Union[dict, Config]] = None, style_channels: int = 512, nkimgs_per_scale: dict = {}, interp_real: Optional[dict] = None, transition_kimgs: int = 600, prev_stage: int = 0, ema_config: Optional[Dict] = None): # get valid style_channels if isinstance(generator, dict): model_style_channels = generator.get('style_channels', None) else: model_style_channels = getattr(generator, 'style_channels', None) if style_channels is not None and model_style_channels is not None: assert style_channels == model_style_channels, ( 'Input \'style_channels\' is unconsistency with ' f'\'generator.style_channels\'. Receive \'{style_channels}\' ' f'and \'{model_style_channels}\'.') else: style_channels = style_channels or model_style_channels super().__init__(generator, discriminator, data_preprocessor, nkimgs_per_scale, None, interp_real, transition_kimgs, prev_stage, ema_config) self.noise_size = style_channels
[docs] def disc_loss(self, disc_pred_fake: Tensor, disc_pred_real: Tensor, fake_data: Tensor, real_data: Tensor) -> Tuple[Tensor, dict]: r"""Get disc loss. StyleGANv1 use non-saturating gan loss and R1 gradient penalty. loss to train the discriminator. .. math: L_{D} = \mathbb{E}_{z\sim{p_{z}}}D\left\(G\left\(z\right\)\right\) - \mathbb{E}_{x\sim{p_{data}}}D\left\(x\right\) + L_{GP} \\ L_{GP} = \lambda\mathbb{E}(\Vert\nabla_{\tilde{x}}D(\tilde{x}) \Vert_2-1)^2 \\ \tilde{x} = \epsilon x + (1-\epsilon)G(z) L_{shift} = Args: disc_pred_fake (Tensor): Discriminator's prediction of the fake images. disc_pred_real (Tensor): Discriminator's prediction of the real images. fake_data (Tensor): Generated images, used to calculate gradient penalty. real_data (Tensor): Real images, used to calculate gradient penalty. Returns: Tuple[Tensor, dict]: Loss value and a dict of log variables. """ losses_dict = dict() losses_dict['loss_disc_fake'] = F.softplus(disc_pred_fake).mean() losses_dict['loss_disc_real'] = F.softplus(-disc_pred_real).mean() # R1 gradient penalty batch_size = real_data.size(0) real_data_ = real_data.clone().requires_grad_() disc_pred = self.discriminator( real_data_, curr_scale=self.curr_scale[0], transition_weight=self._curr_transition_weight) gradients = autograd.grad( outputs=disc_pred, inputs=real_data_, grad_outputs=torch.ones_like(disc_pred), create_graph=True, retain_graph=True, only_inputs=True)[0] # norm_mode is 'HWC' gradients_penalty = gradients.pow(2).reshape(batch_size, -1).sum(1).mean() losses_dict['loss_r1_gp'] = 10 * gradients_penalty parsed_loss, log_vars = self.parse_losses(losses_dict) return parsed_loss, log_vars
[docs] def gen_loss(self, disc_pred_fake: Tensor) -> Tuple[Tensor, dict]: r"""Generator loss for PGGAN. PGGAN use WGAN's loss to train the generator. .. math: L_{G} = -\mathbb{E}_{z\sim{p_{z}}}D\left\(G\left\(z\right\)\right\) + L_{MSE} Args: disc_pred_fake (Tensor): Discriminator's prediction of the fake images. Returns: Tuple[Tensor, dict]: Loss value and a dict of log variables. """ losses_dict = dict() losses_dict['loss_gen'] = -disc_pred_fake.mean() loss, log_vars = self.parse_losses(losses_dict) return loss, log_vars
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