Add NL request for ZBL

src/metatrain/utils/additive/zbl.py

@@ -4,7 +4,7 @@
 import torch
 from ase.data import covalent_radii
 from metatensor.torch import Labels, TensorBlock, TensorMap
-from metatensor.torch.atomistic import ModelOutput, System
+from metatensor.torch.atomistic import ModelOutput, NeighborListOptions, System
 
 from ..data import DatasetInfo
 
@@ -101,49 +101,8 @@ def forward(
         # Assert only one neighbor list for all systems
         neighbor_lists: List[TensorBlock] = []
         for system in systems:
-            nl_options = system.known_neighbor_lists()
-            if len(nl_options) != 1:
-                raise ValueError("ZBL only supports one neighbor list per system.")
-            nl_option = nl_options[0]
-            if nl_option.cutoff < 2.0 * self.largest_covalent_radius:
-                raise ValueError(
-                    "ZBL only supports neighbor lists with a cutoff of at least "
-                    f"{2.0 * self.largest_covalent_radius} Å, since the largest "
-                    f"covalent radius is {self.largest_covalent_radius} Å."
-                )
-            if nl_option.full_list:
-                nl = system.get_neighbor_list(nl_option)
-            else:
-                # convert to full NL
-                half_nl = system.get_neighbor_list(nl_option)
-                half_nl_samples = half_nl.samples.values
-                half_nl_values = half_nl.values
-                nl = TensorBlock(
-                    samples=Labels(
-                        names=half_nl.samples.names,
-                        values=torch.concatenate(
-                            [
-                                half_nl_samples,
-                                torch.concatenate(
-                                    [
-                                        half_nl_samples[:, 1].unsqueeze(-1),
-                                        half_nl_samples[:, 0].unsqueeze(-1),
-                                        -half_nl_samples[:, 2:5],
-                                    ],
-                                    dim=1,
-                                ),
-                            ]
-                        ),
-                    ),
-                    components=half_nl.components,
-                    properties=half_nl.properties,
-                    values=torch.concatenate(
-                        [
-                            half_nl_values,
-                            -half_nl_values,
-                        ],
-                    ),
-                )
+            nl_options = self.requested_neighbor_lists()[0]
+            nl = system.get_neighbor_list(nl_options)
             neighbor_lists.append(nl)
 
         # Find the elements of all i and j atoms
@@ -269,6 +228,14 @@ def get_pairwise_zbl(self, zi, zj, rij):
 
         return e
 
+    def requested_neighbor_lists(self) -> List[NeighborListOptions]:
+        return [
+            NeighborListOptions(
+                cutoff=2.0 * self.largest_covalent_radius,
+                full_list=True,
+            )
+        ]
+
 
 def _phi(r, c, da):
     phi = torch.sum(c.unsqueeze(-1) * torch.exp(-r * da), dim=0)