“…One idea was to use an easy computable subset of permissible functions, what resulted in a weaker optimization capability. Another approach was to determine, for a node in a network, a superset of permissible functions and later check the validity of the perturbation and/or transformation [14]. Selection of a gate to be perturbed as well as the resulting changes are determined based on the structure of the network and on the permissible functions of the nodes.…”