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HomeTechniques and TipsEvolver and RISKOptimizerStarting Values of Adjustable Cells

14.17. Starting Values of Adjustable Cells

Applies to:
Evolver 1.x–7.x
RISKOptimizer 1.x
@RISK Industrial 5.x–7.x (RISKOptimizer)

Does it matter what values are in the adjustable cells when I click the start button for an optimization?

With the genetic algorithm, it matters very much. With the OptQuest engine, it matters very little.

The OptQuest engine was added in Evolver 6.0 and @RISK Industrial 6.0's Optimizer. With those and later versions, you can select the engine on the Engine screen of the Settings dialog.  If you leave the default setting of Automatic, the software will select the engine that seems more appropriate.

With OptQuest, the starting solution is really just a suggested solution, and the algorithm includes a method for generating feasible solutions (all constraints met) even if the initial values don't meet constraints.

The genetic algorithm, which was the only algorithm in earlier releases and is still an option in 6.x, includes backtracking as an important strategy. When Evolver or RISKOptimizer strikes out from where it was standing and that doesn't make the target cell get closer to the goal, then the optimizer backtracks to its previous position and strikes out in a new direction. This has two consequences for the genetic algorithm:

Last edited: 2015-07-23

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