RuntimeError: Expected all tensors to be on the same device, but found at least two devices

问题：RuntimeError: Expected all tensors to be on the same device, but found at least two devices, cpu and cuda:0! (when checking argument for argument mat2 in method wrapper_mm)

原因

参与运算的两个或多个变量，有的在CPU上，有的在GPU上

解决方案

若在gpu上运行，则把所有变量都放在gpu上
如：

device=torch.device('cuda' if torch.cuda.is_available() else 'cpu')
model=GCN_Net(dataset.num_node_features,16,dataset.num_classes).to(device)
data=dataset[0].to(device)