Add support for OneVsRest classification model

[xixici]

When I try to convert one onevsrest model to pmml , there occurs wrong like this:

java.lang.illegalargumentexception: Transformer class org.spache.spark.ml.classification.OneVsRestModel is not supported.

OneVsRest is an example of a machine learning reduction for performing multiclass classification given a base classifier that can perform binary classification efficiently. It is also known as “One-vs-All.”

OneVsRest is implemented as an Estimator. For the base classifier, it takes instances of Classifier and creates a binary classification problem for each of the k classes. The classifier for class i is trained to predict whether the label is i or not, distinguishing class i from all other classes.

Is there a plan to fix it ?

[vruusmann]

Is there a plan to fix it ?

Sure, one day, when there's time.