An Error about MmBackward0

[TenaxLab]

First of all, thank you very much for open sourcing such an excellent project, which I have learned a lot from.
I would like to ask you a question. When executing main.py using the flag-vne algorithm, an error is reported: serWarning: Error detected in MmBackward0. as follows. Have you ever encountered such a problem? How can I solve it?

[GeminiLight]

Thank you for your feedback. I haven’t run into this issue myself. From the log, it looks like NaN values are appearing during the CUDA backward pass (MmBackward0). Could you try running the CPU version and see if the problem still occurs?

[TenaxLab]

Thank you for your reply！I will try running the CPU version! At 2025-11-13 07:39:39, "Tianfu Wang" ***@***.***> wrote: GeminiLight left a comment (GeminiLight/flag-vne#2) Thank you for your feedback. I haven’t run into this issue myself. From the log, it looks like NaN values are appearing during the CUDA backward pass (MmBackward0). Could you try running the CPU version and see if the problem still occurs? — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you authored the thread.Message ID: ***@***.***>

[GeminiLight]

By the way, I’d also recommend taking a look at our Virne project. it’s a more cleanly refactored version and might give you more insights.