initial attempt to interface LheEvent #177

graphicle/base.py

@@ -45,6 +45,40 @@
 DataType = ty.TypeVar("DataType")
 
 
+class LheEventInterface(ty.Protocol):
+    """Interface for a generic Les Houches event.
+
+    :group: base
+
+    .. versionadded:: 0.4.0
+    """
+
+    @property
+    def pdg(self) -> IntVector:
+        """PDG ID codes."""
+        ...
+
+    @property
+    def pmu(self) -> AnyVector:
+        """Four-momenta."""
+        ...
+
+    @property
+    def color(self) -> AnyVector:
+        """Color codes."""
+        ...
+
+    @property
+    def helicity(self) -> HalfIntVector:
+        """Spin / helicity."""
+        ...
+
+    @property
+    def status(self) -> HalfIntVector:
+        """Les Houches specific status codes."""
+        ...
+
+
 class EventInterface(ty.Protocol):
     """Defines the interface for a generic event object expected by
     graphicle's routines. Attributes are stored as numpy arrays, with

graphicle/data.py

@@ -2219,7 +2219,13 @@ def copy(self) -> "ParticleSet":
         return _composite_copy(self)
 
     @classmethod
-    def from_madgraph_table(cls, event_table: str) -> "ParticleSet":
+    def from_lhe_event(cls, event: base.LheEventInterface) -> "ParticleSet":
+        prop_names = ("pdg", "pmu", "color", "helicity", "status")
+        data = cls(**{name: getattr(event, name) for name in prop_names})
+        return data
+
+    @classmethod
+    def _from_lhe_event(cls, event_table: str) -> "ParticleSet":
         schema = {
             "pdg": 0,
             "color": 4,