“…While some researchers tried to find more appropriate parameters in the energy function (Aiyer et al, 1990;Baba, 1989;Biro et al, 1996;Burke, 1994;Gall & Zisssimopoulos, 1999;Gee & Prager, 1995;Hegde et al, 1988;Hopfield & Tank, 1985;Huang, 2005;Sharbaro, 1994;Wilson & Pawley, 1988), others hoped to get better energy functions (Baba, 1989). To date, research work has been extended to every aspect of the Hopfield model (Aarts & Laarhoven, 1985;Abe et al, 1992;Aiyer et al, 1990;Baba, 1989;Biro et al, 1996;Burke, 1994;Hegde et al, 1988;Hopfield & Tank, 1985;Sharbaro, 1994;Wilson & Pawley, 1988), and it is now clear how to correctly map problems onto the network so that invalid solutions never emerge. As for the quality of obtained solutions, while there are indications that the Hopfield model is solely suitable for solving Euclidean TSPs of small size (Wilson & Pawley, 1988), some researchers argue it is unreasonable to take the TSP as the benchmark to measure the optimization ability of the Hopfield model (Sharbaro, 1994).…”