allow_unreachable=True) # allow_unreachable flag RuntimeError: derivative for to_sparse is not implemented

[rockywind]

When I add sparse conv to other code, the error is below.
Traceback (most recent call last): File "train.py", line 215, in <module> main() File "train.py", line 185, in main merge_all_iters_to_one_epoch=args.merge_all_iters_to_one_epoch File "/newnfs/zzwu/08_3d_code/CaDDN_CenterPoint/tools/train_utils/train_utils.py", line 95, in train_model dataloader_iter=dataloader_iter File "/newnfs/zzwu/08_3d_code/CaDDN_CenterPoint/tools/train_utils/train_utils.py", line 42, in train_one_epoch loss.backward() File "/home/CN/zizhang.wu/anaconda3/envs/CaDDN_CenterPoint/lib/python3.7/site-packages/torch/tensor.py", line 221, in backward torch.autograd.backward(self, gradient, retain_graph, create_graph) File "/home/CN/zizhang.wu/anaconda3/envs/CaDDN_CenterPoint/lib/python3.7/site-packages/torch/autograd/__init__.py", line 132, in backward allow_unreachable=True) # allow_unreachable flag RuntimeError: derivative for to_sparse is not implemented

[tianweiy]

sorry, I don't have any clues for this one