diff --git a/artiq/gui/schedule.py b/artiq/gui/schedule.py
index 53d5197e9..1439dfa6d 100644
--- a/artiq/gui/schedule.py
+++ b/artiq/gui/schedule.py
@@ -6,7 +6,8 @@ from quamash import QtGui, QtCore
 from pyqtgraph import dockarea
 
 from artiq.protocols.sync_struct import Subscriber
-from artiq.gui.tools import elide, DictSyncModel
+from artiq.gui.tools import DictSyncModel
+from artiq.tools import elide
 
 
 class _ScheduleModel(DictSyncModel):
diff --git a/artiq/tools.py b/artiq/tools.py
index 7505081f8..819979bb0 100644
--- a/artiq/tools.py
+++ b/artiq/tools.py
@@ -8,6 +8,8 @@ import time
 import collections
 import os.path
 
+import numpy as np
+
 from artiq.language.environment import is_experiment
 from artiq.protocols import pyon