diff --git a/MindSPONGE/applications/rf_diffusion/rfdiffusion/inference/ab_util.py b/MindSPONGE/applications/rf_diffusion/rfdiffusion/inference/ab_util.py
index cc89c7716480e34f8993aa5e09f8135e3adc50cb..29a676e2e45eec0556acd8705b61687c4634f159 100644
--- a/MindSPONGE/applications/rf_diffusion/rfdiffusion/inference/ab_util.py
+++ b/MindSPONGE/applications/rf_diffusion/rfdiffusion/inference/ab_util.py
@@ -24,6 +24,7 @@ import mindspore as ms
 
 from ..kinematics import xyz_to_t2d
 from ..parsers import *
+from .. import util
 from ..util import reference_angles as REF_ANGLES
 from ..util import torsion_can_flip as TOR_CAN_FLIP
 from ..util import torsion_indices as TOR_INDICES