Add PYSCF-AD backend to environment.yml (#107)

* Set pyscf-ad backend to torch

* Changed setting of PYSCFAD-BACKEND to in python file with #noqa

Author: HannaTuerk

examples/periodic-hamiltonian/periodic-hamiltonian.py

@@ -25,14 +25,20 @@
 import requests
 import torch
 from matplotlib.animation import FuncAnimation
-from mlelec.data.derived_properties import compute_eigenvalues
-from mlelec.data.mldataset import MLDataset
 from mlelec.data.qmdataset import QMDataset
-from mlelec.models.equivariant_lightning import LitEquivariantModel, MSELoss
 from mlelec.utils.pbc_utils import blocks_to_matrix
 from mlelec.utils.plot_utils import plot_bands_frame
 
 
+os.environ["PYSCFAD_BACKEND"] = "torch"
+from mlelec.data.derived_properties import compute_eigenvalues  # noqa: E402
+from mlelec.data.mldataset import MLDataset  # noqa: E402
+from mlelec.models.equivariant_lightning import (  # noqa: E402
+    LitEquivariantModel,
+    MSELoss,
+)
+
+
 warnings.filterwarnings("ignore")
 torch.set_default_dtype(torch.float64)