Reproducibility

Q: Under what conditions is an Evolver optimization reproducible?

A: An Evolver optimization will be reproducible if

1. You use the same, fixed random number generator seed. This can be set in the Evolver Options dialog.
2. Your model has not be changed between simulations.
3. You start with exactly the same initial values for all input cells in the model.
4. You have not used functions in your spreadsheet that generate random numbers outside of Evolver's control. Excel's RAND() function is the most common example of this type of function. The numbers generated by RAND() are controlled by Excel, which uses its own independent random number stream.
5. You have not used functions that change depending on when the model is run, such as Excel's TIME() function.
6. You avoid running macros or custom VBA function that do not exactly reproduce their results from simulation to simulation.

Note: Due to a design flaw in Evolver 4.0.4 and earlier, the Recipe solving method might return different results from optimization to optimization in certain cases. This generally only will happen on slower machines. This issue has been corrected in Evolver versions 4.0.5 and later. You can obtain free software updates from www.palisade.com.