Biological Computation

Evolutionary Computation    ◾    137

is put in a channel (the number of channels equals the sequence

length). Every two channels are connected with a comparator ele-

ment, a component that compares two numbers and exchanges

them as needed so that the number in the lower-indexed channel

is the smaller one. e numbers in the sequence move along the

channels and are exchanged if need be. e goal is that at the end of

execution the channels will contain a sorted sequence. e network

in Figure3.10 sorts 10 elements (the horizontal lines are the chan-

nels, and the vertical lines are the comparators). e depth of the

network is dened by the number of nonparallel exchanges, so in

this example the network contains 29 comparators and has a depth

of ...