diff --git a/matlab/simplex_optimization_routine.m b/matlab/simplex_optimization_routine.m
index b06135c62ec9ab9fdbd10d5784c8d2a6a97c5994..98aa783eb27b26baa63d8e83999d65aa56a492e2 100644
--- a/matlab/simplex_optimization_routine.m
+++ b/matlab/simplex_optimization_routine.m
@@ -145,7 +145,7 @@ else
 end
 
 % Set delta parameter.
-if isfield(options,'delta_parameter')
+if isfield(options,'delta_parameter')% Size of the simplex
     delta = options.delta_parameter;
 else
     delta = 0.05;