The numeric vector over which histogram-based binning
is to be performed.
grid_type
A character indicating the choice of binning rule,
with "hist" corresponding to the use of several rules proposed for
optimal histogram construction and "scaled" corresponding to the use
of various pre-set multiples of the square root of the sample size.
max_bins
A numeric indicating the maximum number of bins that
are allowed in the grid for building the histogram based discretization.