Bug: torch eig_solver fail in some systems

[AsymmetryChou]

Describe the bug

Some user reported an issus when plotting bands for some system not included in training dataset.

This is a bug related to torch(v2.5.0) itself. When the user adopted torch with lower version(v2.4.1), the band plotting is successful. Furthermore, the user adopted another eig_solver(numpy) implemented in DeePTB, the plotting is also successful.

Expected behavior

No response

To Reproduce

No response

Environment

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Additional Context

No response

[AsymmetryChou]

Actually, we implemet the numpy eigsolver in DeePTB to solve this problem, as in #264 and #265. However, we need a warning to suggest the user to adopt numpy eig_solver when torch failed.