[Feature Request] how can dpdata.MultiSystems deal with systems without label

[QuantumMisaka]

Summary

If one want to load a dpdata.MultiSystems containing lots of Systems without any label, error will occur, and it seems hard to bypass this problem.

Detailed Description

One can get a dpdata.MultiSystems object containing series of Systems without label, and dump it via dpdata.Multisystems.to_deepmd_npy_mixed().

However, if one trying to read this deepmd/npy/mixed data from the dumping directory, error occurs:

----> 1 testdata = dpdata.MultiSystems.from_file("./Fe-C-ActMat2024-noene-mixed/100", fmt="deepmd/npy/mixed")

File ~/miniconda3/envs/deepmd-310a/lib/python3.12/site-packages/dpdata/system.py:1469, in MultiSystems.from_file(cls, file_name, fmt, **kwargs)
   1466 @classmethod
   1467 def from_file(cls, file_name, fmt: str, **kwargs: Any):
   1468     multi_systems = cls()
-> 1469     multi_systems.load_systems_from_file(file_name=file_name, fmt=fmt, **kwargs)
   1470     return multi_systems

File ~/miniconda3/envs/deepmd-310a/lib/python3.12/site-packages/dpdata/system.py:1493, in MultiSystems.load_systems_from_file(self, file_name, fmt, **kwargs)
   1491 assert fmt is not None
   1492 fmt = fmt.lower()
-> 1493 return self.from_fmt_obj(load_format(fmt), file_name, **kwargs)

File ~/miniconda3/envs/deepmd-310a/lib/python3.12/site-packages/dpdata/system.py:1396, in MultiSystems.from_fmt_obj(self, fmtobj, directory, labeled, **kwargs)
   1394     data_list = fmtobj.from_labeled_system_mix(dd, **kwargs)
   1395     for data_item in data_list:
-> 1396         system_list.append(LabeledSystem(data=data_item, **kwargs))
   1397 else:
   1398     data_list = fmtobj.from_system_mix(dd, **kwargs)

File ~/miniconda3/envs/deepmd-310a/lib/python3.12/site-packages/dpdata/system.py:193, in System.__init__(self, file_name, fmt, type_map, begin, step, data, convergence_check, **kwargs)
    191 if data:
    192     self.data = data
--> 193     self.check_data()
    194     return
    195 if file_name is None:

File ~/miniconda3/envs/deepmd-310a/lib/python3.12/site-packages/dpdata/system.py:221, in System.check_data(self)
    219     raise DataError("data is not a dict!")
    220 for dd in self.DTYPES:
--> 221     dd.check(self)
    222 if sum(self.get_atom_numbs()) != self.get_natoms():
    223     raise DataError(
    224         "Sum of atom_numbs (%d) is not equal to natoms (%d)."  # noqa: UP031
    225         % (sum(self.get_atom_numbs()), self.get_natoms())
    226     )

File ~/miniconda3/envs/deepmd-310a/lib/python3.12/site-packages/dpdata/data_type.py:131, in DataType.check(self, system)
    129             raise RuntimeError("Unsupported type to check shape")
    130 elif self.required:
--> 131     raise DataError(f"{self.name} not found in data")

DataError: energies not found in data

It seems that dpdata.MultiSystems can and only can deal with LabeledSystem but not just System

Further Information, Files, and Links

No response