Heuristic optimisation

1. The computational complexity of many problems means that optimal solutions are unlikely to be found in reasonable time in larger instances. 2. Problems may be ill-defined or data imprecise, so that an optimal solution based on estimated data will almost certainly not be optimal for the actual data. In such a situation it is preferable to obtain a robust solution that will be near-optimal over most scenarios. 3. The user may require several different solutions to make the final choice, particularly in situation where several criteria needed to be balanced using human judgement rather than technical measures.