Frontline Systems, Excel Solver, optimization software, Solver Excel, simulation software
Solver.com
From Frontline Systems, developers of the Excel Solver.

Solver tutorials

Learn to use optimization for resource allocation, and Monte Carlo simulation for risk analysis of your models.


 

Premium Solver for Excel - Alldifferent - Traveling Salesman Problem

Traveling Salesman Problem

In the Premium Solver, you can model problems that involve ordering or permutations of choices easily with an "alldifferent" constraint, which specifies that a set of variables should have integer values from 1 to N, all of them different at the solution.

pspalldiff.jpg (8852 bytes)

Add Constraint dialog:
"dif" selected to specify
an alldifferent constraint.

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.)

Traveling Salesman Problem (43683 bytes)

All Solver engines in the 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.

< Back to Premium Solver Product Overview