add isolated nodes

src/graphnet/models/graphs/__init__.py

@@ -7,4 +7,4 @@
 
 
 from .graph_definition import GraphDefinition
-from .graphs import KNNGraph
+from .graphs import KNNGraph, IsolatedNodes

src/graphnet/models/graphs/graphs.py

@@ -54,3 +54,41 @@ def __init__(
             perturbation_dict=perturbation_dict,
             seed=seed,
         )
+
+
+class IsolatedNodes(GraphDefinition):
+    """A Graph representation where each node is isolated."""
+
+    def __init__(
+        self,
+        detector: Detector,
+        node_definition: NodeDefinition = None,
+        input_feature_names: Optional[List[str]] = None,
+        dtype: Optional[torch.dtype] = torch.float,
+        perturbation_dict: Optional[Dict[str, float]] = None,
+        seed: Optional[Union[int, Generator]] = None,
+    ) -> None:
+        """Construct isolated nodes graph representation.
+
+        Args:
+            detector: Detector that represents your data.
+            node_definition: Definition of nodes in the graph.
+            input_feature_names: Name of input feature columns.
+            dtype: data type for node features.
+            perturbation_dict: Dictionary mapping a feature name to a standard
+                               deviation according to which the values for this
+                               feature should be randomly perturbed. Defaults
+                               to None.
+            seed: seed or Generator used to randomly sample perturbations.
+                  Defaults to None.
+        """
+        # Base class constructor
+        super().__init__(
+            detector=detector,
+            node_definition=node_definition or NodesAsPulses(),
+            edge_definition=None,
+            dtype=dtype,
+            input_feature_names=input_feature_names,
+            perturbation_dict=perturbation_dict,
+            seed=seed,
+        )