Add warning when cluster does not fit in Cage

Author: jvsguerra

AtomPacker/__init__.py

@@ -9,7 +9,7 @@
 the resulting structures.
 """
 
-__version__ = "0.5.1"
+__version__ = "0.5.2"
 __name__ = "AtomPacker"
 license = "GNU GPL-3.0 License"
 

AtomPacker/structure/Cage.py

@@ -329,6 +329,11 @@ def pack(
         ValueError
             If the cage is not loaded, cavity is not detected, or
             clashing_tolerance < 0.
+
+        Warns
+        -----
+        UserWarning
+            If no atoms were packed inside the cavity.
         """
         if self.universe is None:
             raise ValueError("No cage loaded. Please run load() first.")
@@ -397,8 +402,14 @@ def pack(
             verbose=verbose,
         )
 
-        # Create `AtomPacker.structure.Cluster` object
-        self.cluster = Cluster(cluster=_cluster, cavity=self.cavity, log=log)
+        if len(_cluster) > 0:
+            # Create `AtomPacker.structure.Cluster` object
+            self.cluster = Cluster(cluster=_cluster, cavity=self.cavity, log=log)
+        else:
+            warnings.warn(
+                "No atoms were packed: the nanocluster does not fit \
+inside the cavity with the current parameters."
+            )
 
     def preview(
         self,