TN: fix callable j for classical spin system builders

jcmgray · jcmgray · commit fd768183caf7 · 2025-02-05T11:35:34.000-08:00
diff --git a/quimb/tensor/tensor_builder.py b/quimb/tensor/tensor_builder.py
@@ -2118,7 +2118,7 @@ def parse_j_coupling_to_function(j):
     function.
     """
     if callable(j):
-        return j
+        return functools.cache(j)
 
     elif isinstance(j, dict):
 
