Source code for dalib.translation.cyclegan.loss
"""
Modified from https://github.com/junyanz/pytorch-CycleGAN-and-pix2pix
@author: Junguang Jiang
@contact: [email protected]
"""
import torch.nn as nn
import torch
[docs]class LeastSquaresGenerativeAdversarialLoss(nn.Module):
"""
Loss for `Least Squares Generative Adversarial Network (LSGAN) <https://arxiv.org/abs/1611.04076>`_
Args:
reduction (str, optional): Specifies the reduction to apply to the output:
``'none'`` | ``'mean'`` | ``'sum'``. ``'none'``: no reduction will be applied,
``'mean'``: the sum of the output will be divided by the number of
elements in the output, ``'sum'``: the output will be summed. Default: ``'mean'``
Inputs:
- prediction (tensor): unnormalized discriminator predictions
- real (bool): if the ground truth label is for real images or fake images. Default: true
.. warning::
Do not use sigmoid as the last layer of Discriminator.
"""
def __init__(self, reduction='mean'):
super(LeastSquaresGenerativeAdversarialLoss, self).__init__()
self.mse_loss = nn.MSELoss(reduction=reduction)
def forward(self, prediction, real=True):
if real:
label = torch.ones_like(prediction)
else:
label = torch.zeros_like(prediction)
return self.mse_loss(prediction, label)
[docs]class VanillaGenerativeAdversarialLoss(nn.Module):
"""
Loss for `Vanilla Generative Adversarial Network <https://arxiv.org/abs/1406.2661>`_
Args:
reduction (str, optional): Specifies the reduction to apply to the output:
``'none'`` | ``'mean'`` | ``'sum'``. ``'none'``: no reduction will be applied,
``'mean'``: the sum of the output will be divided by the number of
elements in the output, ``'sum'``: the output will be summed. Default: ``'mean'``
Inputs:
- prediction (tensor): unnormalized discriminator predictions
- real (bool): if the ground truth label is for real images or fake images. Default: true
.. warning::
Do not use sigmoid as the last layer of Discriminator.
"""
def __init__(self, reduction='mean'):
super(VanillaGenerativeAdversarialLoss, self).__init__()
self.bce_loss = nn.BCEWithLogitsLoss(reduction=reduction)
def forward(self, prediction, real=True):
if real:
label = torch.ones_like(prediction)
else:
label = torch.zeros_like(prediction)
return self.bce_loss(prediction, label)
[docs]class WassersteinGenerativeAdversarialLoss(nn.Module):
"""
Loss for `Wasserstein Generative Adversarial Network <https://arxiv.org/abs/1701.07875>`_
Args:
reduction (str, optional): Specifies the reduction to apply to the output:
``'none'`` | ``'mean'`` | ``'sum'``. ``'none'``: no reduction will be applied,
``'mean'``: the sum of the output will be divided by the number of
elements in the output, ``'sum'``: the output will be summed. Default: ``'mean'``
Inputs:
- prediction (tensor): unnormalized discriminator predictions
- real (bool): if the ground truth label is for real images or fake images. Default: true
.. warning::
Do not use sigmoid as the last layer of Discriminator.
"""
def __init__(self, reduction='mean'):
super(WassersteinGenerativeAdversarialLoss, self).__init__()
self.mse_loss = nn.MSELoss(reduction=reduction)
def forward(self, prediction, real=True):
if real:
return -prediction.mean()
else:
return prediction.mean()
