Palisade Knowledge Base

HomeTroubleshooting@RISK for Excel: SimulationMultiple CPU — Blocks of Errors in Simulated Outputs

4.8. Multiple CPU — Blocks of Errors in Simulated Outputs

Applies to: @RISK, all releases

When I disable Multiple CPU, my simulation runs just fine. But when I enable Multiple CPU, the Simulation data window shows blocks of error values in my outputs. For example, I might have numbers for iterations 1–100 and 201–300, but "Error" for iterations 101–200 and 301–400.

There are a few inherent limitations to running multiple CPUs. These come about because a "worker" CPU doesn't have access to the data developed by any other CPU; only the "master" does. During simulation, each worker has a private copy of your workbook. The master tells each worker which iterations to run; the worker runs those iterations and passes the values of @RISK inputs and outputs back to the master. At the end of the simulation, the workers' private copies of the worksheet are destroyed.

If this is your issue, the simplest solution is to go into Simulation Settings and select Multiple CPU: Disabled. If that makes the simulation take too long to run, you're going to have to make some changes in your workbook:

Last edited: 2017-02-07

This page was: Helpful | Not Helpful