Hi,
I a new to PyTorch and also to deep learning. I am trying to produce a segmentation within four classes (background and 3 objects).
I obtained the U-Net model from online existing ones.
I do not understand the error I get: does it arise from the model, or cuda use:

RuntimeError                              Traceback (most recent call last)
 in 
11         l = torch.nn.functional.cross_entropy(prediction, y_train_batch)
12         my_optimizer.zero_grad()
—> 13         l.backward()
14         my_optimizer.step()
15         train_loss += l
/usr/local/lib/python3.6/site-packages/torch/tensor.py in backward(self, gradient, retain_graph, create_graph)
91                 products. Defaults to False.
92         “”"
—> 93         torch.autograd.backward(self, gradient, retain_graph, create_graph)
94
95     def register_hook(self, hook):
/usr/local/lib/python3.6/site-packages/torch/autograd/init.py in backward(tensors, grad_tensors, retain_graph, create_graph, grad_variables)
88     Variable._execution_engine.run_backward(
89         tensors, grad_tensors, retain_graph, create_graph,
—> 90         allow_unreachable=True)  # allow_unreachable flag
91
92
RuntimeError: cuda runtime error (59) : device-side assert triggered at /pytorch/aten/src/THCUNN/generic/Threshold.cu:67
Please could someone give me indications?