Dimitris Athanasiou c141c1dd89
[7.x][ML] Stratified cross validation split for classification (#54087) (#54104)
As classification now works for multiple classes, randomly
picking training/test data frame rows is not good enough.
This commit introduces a stratified cross validation splitter
that maintains the proportion of the each class in the dataset
in the sample that is used for training the model.

Backport of #54087
2020-03-24 18:47:36 +02:00
..