LogL1Loss

neural_filters/LogMSELoss.py → neural_filters/log_loss.py

 import torch
 from torch.nn import MSELoss
+from torch.nn import L1Loss
+
 
 class LogMSELoss(MSELoss):
     r"""Creates a criterion that measures the logarithmic mean squared error between
@@ -45,10 +47,62 @@ class LogMSELoss(MSELoss):
         >>> output = loss(input, target)
         >>> output.backward()
     """
+
+    def __init__(self, size_average=True, reduce=True, epsilon=0.05):
+        super().__init__(size_average, reduce)
+        self.epsilon = epsilon
+
+    def forward(self, input, target):
+        loss = super().forward(input, target)
+        return torch.log(loss + self.epsilon)
+
+class LogL1Loss(L1Loss):
+    r"""Creates a criterion that measures the logarithm of the mean absolute value of the
+    element-wise difference between input `x` and target `y`:
+
+    :math:`{loss}(x, y)  = \log( 1/n \sum |x_i - y_i| + epsilon )`
+
+    `x` and `y` arbitrary shapes with a total of `n` elements each.
+
+    The sum operation still operates over all the elements, and divides by `n`.
+
+    The division by `n` can be avoided if one sets the constructor argument
+    `size_average=False`.
+
+    The epsilon is a positive float used to avoid log(0) leading to NaN.
+
+    Args:
+        size_average (bool, optional): By default, the losses are averaged
+           over observations for each minibatch. However, if the field
+           size_average is set to ``False``, the losses are instead summed for
+           each minibatch. Ignored when reduce is ``False``. Default: ``True``
+        reduce (bool, optional): By default, the losses are averaged or summed
+           for each minibatch. When reduce is ``False``, the loss function returns
+           a loss per batch element instead and ignores size_average.
+           Default: ``True``
+        epsilon (float, optional): add a small positive term to the MSE before
+            taking the log to avoid NaN with log(0). Default: ``0.05``
+
+    Shape:
+        - Input: :math:`(N, *)` where `*` means, any number of additional
+          dimensions
+        - Target: :math:`(N, *)`, same shape as the input
+        - Output: scalar. If reduce is ``False``, then
+          :math:`(N, *)`, same shape as the input
+
+    Examples::
+
+        >>> loss = neural_filters.LogL1Loss()
+        >>> input = autograd.Variable(torch.randn(3, 5), requires_grad=True)
+        >>> target = autograd.Variable(torch.randn(3, 5))
+        >>> output = loss(input, target)
+        >>> output.backward()
+    """
+
     def __init__(self, size_average=True, reduce=True, epsilon=0.05):
-        super(LogMSELoss, self).__init__(size_average, reduce)
+        super().__init__(size_average, reduce)
         self.epsilon = epsilon
 
     def forward(self, input, target):
-        loss = super(LogMSELoss, self).forward(input, target)
-        return torch.log(loss + self.epsilon)
+        loss = super().forward(input, target)
+        return torch.log(loss + self.epsilon)
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