[BugFix] Failing to add graphs when MockDevice is used

[lmoroml]

Extractors fail to add graphs when MockDevice is used as device. Specifically, the parameter max_atom_num is not defined for this device and therefore the is_embeddable() (BaseGraph) method fails.

[RolandMacDoland]

Thanks @lmoroml. Could you please add a code example that fails and the error that it returns ? Thanks again for your help.

[lmoroml]

Absolutely. Here a minimal example code:

from pathlib import Path
from qek.shared.retrier import PygRetrier

import pulser as pl
import qek.data.graphs as qek_graphs
import qek.data.extractors as qek_extractors

import torch_geometric.datasets as pyg_dataset

# Load the original PTC-FM dataset.
# We use PygRetrier to retry the download if it fails.
og_ptcfm = PygRetrier().insist(pyg_dataset.TUDataset, root="dataset", name="PTC_FM")

# Use the Qutip Extractor.
extractor = qek_extractors.QutipExtractor(
    # Once computing is complete, data will be saved in this file.
    path=Path("saved_data.json"),
    compiler=qek_graphs.PTCFMCompiler(),
    device=pl.devices.MockDevice
)

# Here's the error
extractor.add_graphs([og_ptcfm[0]])

and here the error I get:

Traceback (most recent call last):
File "minimal_code_error.py", line 22, in
extractor.add_graphs([og_ptcfm[0]])
File "quantum-evolution-kernel/qek/data/extractors.py", line 339, in add_graphs
if processed.is_embeddable():
^^^^^^^^^^^^^^^^^^^^^^^^^
File "quantum-evolution-kernel/qek/data/graphs.py", line 177, in is_embeddable
if self.pyg.num_nodes > self.device.max_atom_num:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: '>' not supported between instances of 'int' and 'NoneType'

[RolandMacDoland]

Thanks @lmoroml