rv
Regroups the flat rvParameterData DTOs into the nested map form that ksl.utilities.random.rvariable.parameters.RVParameterSetter.changeParameters expects.
The outer map is keyed by RVParameterData.rvName; the inner map is keyed by RVParameterData.paramName with the corresponding RVParameterData.paramValue.
Any consumer that needs to pass RV parameter changes to an ksl.utilities.random.rvariable.parameters.RVParameterSetter can use this property directly instead of re-implementing the grouping.