diff --git a/python/dune/perftool/sumfact/realization.py b/python/dune/perftool/sumfact/realization.py
index 58d7a46c3916ae707a1898401dc65e5a16f38b96..7b84f4f6a37396564d810867529d04193da8b99e 100644
--- a/python/dune/perftool/sumfact/realization.py
+++ b/python/dune/perftool/sumfact/realization.py
@@ -26,6 +26,7 @@ from dune.perftool.sumfact.vectorization import attach_vectorization_info
 from dune.perftool.sumfact.sumfact import sumfact_iname
 
 import loopy as lp
+import numpy as np
 import pymbolic.primitives as prim