Double Backward with Custom Functions — PyTorch Tutorials 1 ...
pytorch.org › tutorials › intermediateCustom functions implicitly affects grad mode in two ways: During forward, autograd does not record any the graph for any operations performed within the forward function. When forward completes, the backward function of the custom function becomes the grad_fn of each of the forward’s outputs; During backward, autograd records the computation graph used to compute the backward pass if create_graph is specified; Next, to understand how save_for_backward interacts with the above, we can ...
Custom Loss Function with Backward Method - autograd ...
discuss.pytorch.org › t › custom-loss-function-withJul 26, 2018 · import torch class MyReLU(torch.autograd.Function): @staticmethod def forward(ctx, input): ctx.save_for_backward(input) return input.clamp(min=0) @staticmethod def backward(ctx, grad_output): input, = ctx.saved_tensors #print(grad_output) grad_input = grad_output.clone() grad_input[input < 0] = 0 return grad_input class MyLoss(torch.autograd.Function): @staticmethod def forward(ctx, y, y_pred): ctx.save_for_backward(y, y_pred) return (y_pred - y).pow(2).sum() @staticmethod def backward(ctx ...