\$title Traveling Salesman Problem - Two (TSP2,SEQ=178) \$onText This is the second problem in a series of traveling salesman problems. The formulation in this model uses subtour elimination constraints of the form u(i) - u(j) + n*x(i,j) <= n - 1 Additional information can be found at: http://www.gams.com/modlib/adddocs/tsp2doc.htm Kalvelagen, E, Model Building with GAMS. forthcoming de Wetering, A V, private communication. Keywords: mixed integer linear programming, traveling salesman problem, Miller- Tucker-Zemlin subtour elimination \$offText \$eolCom // \$include br17.inc Set ij(ii,jj) 'exclude first row and column'; ij(ii,jj) = ord(ii) > 1 and ord(jj) > 1; Variable u(ii) 'subtour elimination strategy 3'; Equation se(ii,jj) 'subtour elimination constraints'; se(ij(i,j)).. u(i) - u(j) + card(i)*x(i,j) =l= card(i) - 1; Model tsp / objective, rowsum, colsum, se /; * Try a small problem first - first six cities i(ii) = ord(ii) <= 6; option optCr = 0.05; solve tsp min z using mip; display x.l; * Try a bit larger problem - 10 cities i(ii) = ord(ii) <= 10; option limCol = 0, limRow = 0; solve tsp min z using mip;