HomeTechniques and Tips@RISK Simulation: Numerical ResultsMore Than 50,000 Iterations to Converge

6.2. More Than 50,000 Iterations to Converge

Applies to: @RISK 6.1.1 and newer

I have set up convergence, with iterations set to Auto, but @RISK stops at 50,000 iterations although not all of my outputs have converged.

By default, @RISK stops at 50,000 iterations rather than keep iterating indefinitely.  However, it is true that some models will eventually converge, but at some point after 50,000 iterations.  You could set a higher number of iterations explicitly instead of Auto, but then you lose convergence monitoring.

Beginning with @RISK 6.1.1, you can change that 50,000-iteration limit for convergence monitoring.  Create a workbook-level name RiskMaxItersForAutoStop with a value such as =100000.  (The leading = sign is required.)  With iterations set to Auto, @RISK will stop when outputs converge, or when the RiskMaxItersForAutoStop number of iterations is reached, whichever happens first. 

To create a workbook-level name in Excel 2007, Excel 2010, and Excel 2013, click Formulas » Name Manager » New.  Enter the name RiskMaxItersForAutoStop.  In the Refers-to box, enter your desired maximum number of iterations for convergence monitoring, preceded by the = sign.  Click OK and then Close.

To create a workbook-level name in Excel 2003, click Insert » Name » Define.  In the box at the top, enter the name RiskMaxItersForAutoStop.  In the Refers-to box, enter your desired maximum number of iterations for convergence monitoring, preceded by the = sign.  Click Add and then OK.

During simulation, the progress window at the lower left of your screen shows a percent complete.  If iterations is Auto, @RISK doesn't know how many iterations will be needed until convergence has occurred, so it computes the percent complete on a basis of 100% = 50,000 iterations.  If you have set RiskMaxItersForAutoStop to a larger number, and more than 50,000 iterations are needed, the percent complete will go above 100%.

Last edited: 2015-06-24

This page was: Helpful | Not Helpful