Reducers are functions that tell the partition algorithm how
to reduce the data. as_reducer() is a helper function to create new
reducers to be used in partitioners. partitioners can be created with
as_partitioner().
reduce_first_component() returns the first component from the
principal components analysis of the target variables.
reduce_first_component(.partition_step)a partition_step object
a partition_step object
Other reducers:
as_reducer(),
reduce_kmeans(),
reduce_scaled_mean()