Applies to: @RISK 5.5 and Up

How to ensure unique values across iterations from a RiskDiscrete distribution

 

Problem
You are using a RiskDiscrete distribution and want each simulation iteration to draw a unique value, with no duplicates across iterations.

 

Explanation
RiskDiscrete samples with replacement, meaning the same value can appear in multiple iterations. Because of this behavior, RiskDiscrete cannot guarantee uniqueness across iterations on its own.

 

Solution
Use the RiskResample distribution instead of RiskDiscrete. RiskResample allows sampling from a defined list of values without replacement, ensuring that each iteration receives a unique value.

 

How to configure RiskResample
Set the first argument of RiskResample to control the sampling method. Use sampling method 1 if you want @RISK to step through your list of values in a specified order. Use sampling method 3 if you want values selected randomly from the list without replacement. In both cases, each value will be used only once.

 

Important limitation
If the number of simulation iterations exceeds the number of values in your list, RiskResample will return an error for the extra iterations. To avoid this, ensure that the iteration count does not exceed the number of available values.