Reference Issues/PRs

n/a

What does this implement/fix? Explain your changes.

I noticed that there were extra arguments in node_split_best and node_split_random that need not be in the function signatures, and they simply complicate the function signature. The changes are inline with how the rest of the splitter parameters are used (i.e. there is a reference defined within the inline function rather than passing in the parameter explicitly).

This should be a super quick review.

cc: @thomasjpfan

Any other comments?

Note: in an ideal world we would also not pass in Criterion criterion since that is an attribute of the Splitter splitter object. But one cannot define Criterion within the nogil node_split_best and node_split_random functions. That is the following is not possible:

cdef inline int node_split_best(
    Splitter splitter,
    Partitioner partitioner,
    SplitRecord* split,
    ParentInfo* parent_record,
) except -1 nogil:
    """Find the best split on node samples[start:end]

    Returns -1 in case of failure to allocate memory (and raise MemoryError)
    or 0 otherwise.
    """
    cdef Criterion criterion = splitter.criterion

ref: https://stackoverflow.com/questions/68278706/is-nogil-safe-when-accessing-cython-extension-type-members