The assignment problem is an archetypical combinatorial optimization p
roblem having widespread applications, This paper presents two recurre
nt neural networks, a continuous-time one and a discrete-time one, for
solving the assignment problem, Because the proposed recurrent neural
networks solve the primal and dual assignment problems simultaneously
, they are named as the primal-dual assignment networks. The primal-du
al assignment networks are guaranteed to make optimal assignment regar
dless of initial conditions, Unlike the primal or dual assignment netw
ork, there is no time-varying design parameter in the primal-dual assi
gnment networks, Therefore, they are more suitable for hardware implem
entation. The performance and operating characteristics of the primal-
dual assignment networks are demonstrated by means of illustrative exa
mples.