Skip to content

This code sample shows how using the dual version of an intuitive model can yield expressivity and performance benefits.

Notifications You must be signed in to change notification settings

pberlandier/model-duality

Folders and files

NameName
Last commit message
Last commit date

Latest commit

 

History

11 Commits
 
 
 
 
 
 
 
 
 
 

Repository files navigation

Using a dual model for expressivity and performance

This repo shows how using a dual view on an object model can improve the expressivity and performance of business decisions defined with business rules.

The example implemented is loosely based on worker compensation / benefits calculation: a worker is associated with a time period that captures different characteristics for each day in that period, such as whether the day is a site holiday or the worker has worked on that specific day. A simple object model for the rules can rely on a class that represents a Day with one attribute for each characteristic and create a Day instance for each day in the time period.

The issue with such a design is that it leads to:

  • Quasi-linear degradation of the runtime performance as the number of days in the considered time period is increasing.

  • Lower expressivity as most of the operations performed by the rules are about computing aggregated values on the time period.

This is when taking a dual point of view on the model is useful. In our example, instead of using a list of day instances that are characterized by a set of properties, we can choose to use a set of properties that are characterized by the set of days to which they apply. This idea is illustrated by the figure below:

  • The red outline shows the simple model, where the days are entities with properties such as site holiday or worked and a decision service execution involves potentially thousands of instances of day entities.

  • The green outline is the dual model, where property objects capture the property values for each day. Here, there’s only a handful of property objects to manage.

Once the dual view is adopted, an optimized implementation can be selected. In our example, the collection of boolean values for a property can be efficiently represented using a Java Bitset. Such an implementation is compact in memory and allows to perform batch logical operations on properties.

For categorical (non-boolean) properties, we can keep a bit-set implementation by using technique such as one-hot encoding, commonly used for machine learning models.

The projects in this repo are based on ODM 8.10.4.

About

This code sample shows how using the dual version of an intuitive model can yield expressivity and performance benefits.

Topics

Resources

Stars

Watchers

Forks

Packages

No packages published

Languages