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 the 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 the Premium Solver
Platform supports this new type of constraint. The Branch
& Bound process used by the LP/Quadratic 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.
Field-installable Solver engines also
support the "alldifferent" constraint, implementing it in
different ways. This allows you to model the problem in a high-level
way, and try a variety of Solver engines to see which one yields the
best performance on your problem.
Back to Premium Solver
Platform Product Overview
