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Yearstretch GASolver Reference

Solution Options


Solving Options

These options are concerned with controlling the solver once it has started. They are set when you intend to start solving so you must have built your model and be ready to start solving it.

To set the GASolver Solving Options:

  1. Click the Start button from the main dialog.

  1. Enter your option choices as follows:

Start Point

  • Evolve a solution from most scratch

If this is the first solution run then GASolver will only start looking for a new solution from scratch, e.g. clearing all extant data from its gene pool.

  • Include current sheet values

Performance Point: This is a very powerful option and can save hours of CPU time.  If you have been manually tuning a model and want to try and improve the results with GASolver, or you have a previous GASolver optimised model or you have some other start point you would like to use, then check this box to have the current input values included in the new solution process.

GASolver will create a population using its own internal rules and then overwrite one of these with your current input cell values. This allows you to seed the population with a gene set you may already know to be a good solution and this may save much solution search time.

If the current sheet input cell values form a good solution then GASolver will retain it and eventually its genes will peculate throughout the main population. If however your current input cell values are not as good as the GASolver created ones then they will die out and be replaced as usual by the internally generated values. Either way the process is robust and will lead to a best solution formed from either the internal values or the current sheet values or a combination of both.

Please note that if you include your own sheet input values then GASolver will NOT check them to see if they meet the input range conditions that you may have set for the automated input cell value creations.

Note that this option is often used in conjunction with the option when setting input ranges. See the Input Cell Value Range section.

  • Continue solving from most recent position

If there is a previous valid run, e.g. at least one whole generation has been completed, then GASolver may be told to continue searching from the last solution point.

End Point

Tell GASolver how to stop.

  • Halt solver manually

GASolver will continue running until you halt it by pressing the Pause button on the progress dialog.

If there is a previous valid run, e.g. at least one whole generation has been completed, then GASolver may be told to continue searching from the latest solution point.

  • Halt solver automatically when

  • target cell is within <value>

The solver will stop when it has a solution that is within N of the target value where N is the convergence. Thus a target value of 10 with a convergence of 0.5 will accept solutions from 10 - 0.5 to 10 + 0.5 or 9.5 through 10.5.

Setting a convergence value of 0 will force GASolver only to accept an exact match to your target value. Thus a target value of 10 with a convergence of 0 will only accept 10 as a solution.

Convergence only applies when the target goal is set to 'equal to' from the main dialog, e.g. convergence values have no effect on target goals of minimum or maximum.

Performance Point: The smaller the 'target cell is within' value the more accurate the solution but the longer the solution time. The larger the convergence value the less accurate the solution but the shorter the solution time.

  • when generations reach <value>

GASolver will stop when the specified number of generations has been completed. The more generations you allow the better the solution. Generations may be loosely thought of as iterations. If the population is set at 100 and the survivors are set to 50 then each generation after the first one will cause at least 50 recalculations of your worksheet.

  • when processing time exceeds <value>

GASolver will stop when the specified number of minutes has been exceeded. Enter the maximum number of minutes you want to allow for a solution. The more you allow the better the solution. GASolver will not however stop part way through a generation so the current generation will be completed before processing is halted by the timer.

Beep on solution result

Check this option to have GASolver beep your computer's speaker a few times when it has completed a solution run.

  1. Click OK to start solving.

See Also Setting Options

 

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