How to pass constant values to the PMML from PMMLPipeline in a custom transformer as an argument about sklearn2pmml

[vruusmann]

Duplicate of jpmml/jpmml-sklearn#44

Will add a sample transformer class com.mycompany.PowerFunction into the SkLearn2PMML-Plugin project later today (or tomorrow).

There is no need to create a special-purpose Java-backed UDF for this. PMML provides a built-in function pow for raising numbers to arbitrary powers:

<Apply function="pow">
  <FieldRef field="number"/>
  <Constant dataType="integer">3</Constant>
</Apply>

[chandimsett]

Thanks for adding the function. For my use case, I need to know how to pass the argument to a custom transformer function, from the PMMLPipeline mapper. To be more specific, how do I create a Data Frame mapper which enables me to pass an argument for the respective custom transformer function, so that it creates a <Constant> markup carrying my argument in the PMML file for my custom transformer.