diff --git a/modules/util/util.py b/modules/util/util.py
index 8b29f733efc4b3277ec3360e5ffa42388dd90112..423fc7c38f9f0628832bdc47804d150f63ef888e 100644
--- a/modules/util/util.py
+++ b/modules/util/util.py
@@ -201,6 +201,7 @@ def minimize_quadratic(xa, xb, xc, ya, yb, yc):
     return x_m
 
 
+# Return index of nda closest to value. nda must be 1d
 def value_to_index(nda, value):
     diff = np.abs(nda - value)
     idx = np.argmin(diff)