diff --git a/qpms/lattices.py b/qpms/lattices.py
index 5cdba38..4fc5a24 100644
--- a/qpms/lattices.py
+++ b/qpms/lattices.py
@@ -8,35 +8,7 @@ import scipy
 import sys
 from qpms_c import get_mn_y, trans_calculator # TODO be explicit about what is imported
 from .qpms_p import cart2sph, nelem2lMax # TODO be explicit about what is imported
-
-def _time_b(active = True, name = None, step = None):
-    '''
-    Auxiliary function for keeping track of elapsed time.
-    Returns current time (to be used by _time_e).
-    '''
-    now = time.time()
-    if active:
-        if not name:
-            name = sys._getframe(1).f_code.co_name
-        if step:
-            print('%.4f: %s in function %s started.' % (now, step, name), file = sys.stderr)
-        else:
-            print('%.4f: Function %s started.' % (now, name), file=sys.stderr)
-        sys.stderr.flush()
-    return now
-
-def _time_e(start_time, active = True, name = None, step = None):
-    now = time.time()
-    if active:
-        if not name:
-            name = sys._getframe(1).f_code.co_name
-        if step:
-            print('%.4f: %s in function %s finished (elapsed %.2f s).' 
-                    % (now, step, name, now - start_time), file = sys.stderr)
-        else:
-            print('%.4f: Function %s finished (elapsed %.2f s).' 
-                    % (now, name, now - start_time), file = sys.stderr)
-        sys.stderr.flush()
+from .timetrack import _time_b, _time_e
 
 class Scattering(object):
     '''
diff --git a/qpms/timetrack.py b/qpms/timetrack.py
new file mode 100644
index 0000000..358c2b8
--- /dev/null
+++ b/qpms/timetrack.py
@@ -0,0 +1,32 @@
+import time
+import sys
+
+def _time_b(active = True, name = None, step = None):
+    '''
+    Auxiliary function for keeping track of elapsed time.
+    Returns current time (to be used by _time_e).
+    '''
+    now = time.time()
+    if active:
+        if not name:
+            name = sys._getframe(1).f_code.co_name
+        if step:
+            print('%.4f: %s in function %s started.' % (now, step, name), file = sys.stderr)
+        else:
+            print('%.4f: Function %s started.' % (now, name), file=sys.stderr)
+        sys.stderr.flush()
+    return now
+
+def _time_e(start_time, active = True, name = None, step = None):
+    now = time.time()
+    if active:
+        if not name:
+            name = sys._getframe(1).f_code.co_name
+        if step:
+            print('%.4f: %s in function %s finished (elapsed %.2f s).' 
+                    % (now, step, name, now - start_time), file = sys.stderr)
+        else:
+            print('%.4f: Function %s finished (elapsed %.2f s).' 
+                    % (now, name, now - start_time), file = sys.stderr)
+        sys.stderr.flush()
+