...

Multiple choices exist to address the use-cases targeted by this design doc. In the following, we explain the design principle followed by the proposed design, to hopefully make the understanding of the design choices more intuitive.

1) As much as possible, the API design should allow users to address the new use-case while still enjoying the existing functionalitiesbenefits.

For example, the existing Pipeline class allows users to compose an Estimator from a linear chain of Estimator/Transformer, without requiring users to specify this linear chain twice (see Background Section for more detail).

Correspondingly, as we extend the Flink ML API to suppose DAG of Estimator/Transformer, we believe the APIs should provide this functionality with similar benefits:

• Allow users to compose an Estimator from a DAG of Estimator/Transformer, without requiring users to specify this DAG twice.

Public Interfaces

This FLIP proposes quite a few changes and additions to the existing Flink ML APIs. We first describe the proposed API additions and changes, followed by the API code of interfaces and classes after making the proposed changes.

...