Reimplement preference converter

src/matching/convert.py

@@ -4,14 +4,17 @@
 from scipy.stats import rankdata
 
 
-def preference_to_rank(preference, others):
-    """Convert a preference dictionary to a rank array."""
+def preference_to_rank(preferences, others):
+    """Convert a preference list dictionary to a rank array."""
 
-    rank = np.array(
-        [[others.index(o) for o in prefs] for prefs in preference.values()]
-    )
+    sorted_preferences = sorted(preferences.items(), key=lambda x: x[0])
+    sorted_others = sorted(others)
+    ranks = [
+        [prefs.index(o) if o in prefs else len(others) for o in sorted_others]
+        for _, prefs in sorted_preferences
+    ]
 
-    return rank
+    return np.array(ranks)
 
 
 def utility_to_rank(utility):