When creating a roll-up rule, DUCO allows you to use a field once per rule. If you try to use the same field twice DUCO will give you the following message:
In this example the user is trying to roll-up individual trade executions. The end results will need to sum the quantity and provide a weighted average price, weighted by quantity.
To accomplish this you need to add another match field using the same exact fields as the original data element in the roll-up. ***Please note if you have rules in the original match field, you must recreate that same exact rule in the new matched field. ***
In this example we had the original match field of Quantity and added in a second match field for Quantity 2.
Then you can add a Rules & Rule Set to ignore the Quantity 2 field.
Next remove the new field from the view using reported fields.
Finally update your roll-up rule to calculate the weighted average price by Quantity 2.
You can now see that the error is gone and the roll-up rule will work successfully.