  Test functions are important to validate new optimization algorithms and to
compare the performance of various algorithms. There are many test functions in
the literature, but there is no standard list or set of test functions one has
to follow. New optimization algorithms should be tested using at least a subset
of functions with diverse properties so as to make sure whether or not the
tested algorithm can solve certain type of optimization efficiently. Here we
provide a selected list of test problems for unconstrained optimization.
