Premium Solver Pro for Excel - Alldifferent ConstraintsTraveling Salesman Problem
Problems involving ordering or permutations of choices are very difficult to model using conventional constraints, even with integer variables. An example is the famous Traveling Salesman Problem (TSP), where a salesman must choose the order of cities to visit so as to minimize travel time, and each city must be visited exactly once. In Premium Solver Platform, you can model this kind of problem easily with an "alldifferent" constraint. (Click on the worksheet below to see it full size.) All Solver engines in Premium Solver supports this new type of constraint. The Branch & Bound process used by the LP Simplex and GRG nonlinear Solvers is extended to handle "alldifferent" constraints as a native type, and the hybrid Evolutionary / Classical Solver implements these constraints using mutation and crossover operators for permutations. |
