diff --git a/src/pineko/evolve.py b/src/pineko/evolve.py
index ceba30dd..84e603d2 100644
--- a/src/pineko/evolve.py
+++ b/src/pineko/evolve.py
@@ -426,7 +426,7 @@ def prepare(operator):
         fktable = grid.evolve_with_slice_iter2(
             prepare(operators1),
             prepare(operators2),
-            ren1=mur2_grid,
+            ren1=xir*xir*mur2_grid,
             alphas=alphas_values,
             xi=(xir, xif),
             order_mask=order_mask,
@@ -434,7 +434,7 @@ def prepare(operator):
     else:
         fktable = grid.evolve_with_slice_iter(
             prepare(operators1),
-            ren1=mur2_grid,
+            ren1=xir*xir*mur2_grid,
             alphas=alphas_values,
             xi=(xir, xif),
             order_mask=order_mask,