LightGBM

Pr4 advanced method monotone constraints (#3264)

* No need to pass the tree to all fuctions related to monotone constraints because the pointer is shared.

* Fix OppositeChildShouldBeUpdated numerical split optimisation.

* No need to use constraints when computing the output of the root.

* Refactor existing constraints.

* Add advanced constraints method.

* Update tests.

* Add override.

* linting.

* Add override.

* Simplify condition in LeftRightContainsRelevantInformation.

* Add virtual destructor to FeatureConstraint.

* Remove redundant blank line.

* linting of else.

* Indentation.

* Lint else.

* Replaced non-const reference by pointers.

* Forgotten reference.

* Leverage USE_MC for efficiency.

* Make constraints const again in feature_histogram.hpp.

* Update docs.

* Add "advanced" to the monotone constraints options.

* Update monotone constraints restrictions.

* Fix loop iterator.

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Fix loop iterator.

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Remove superfluous parenthesis.

* Fix loop iterator.

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Fix loop iterator.

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Fix loop iterator.

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Fix loop iterator.

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Fix loop iterator.

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Fix loop iterator.

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Fix loop iterator.

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Fix loop iterator.

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Remove std namespace qualifier.

* Fix unsigned_int size_t comparison.

* Set num_features as int for consistency with the rest of the codebase.

* Make sure constraints exist before recomputing them.

* Initialize previous constraints in UpdateConstraints.

* Update monotone constraints restrictions.

* Refactor UpdateConstraints loop.

* Update src/io/config.cpp

Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* Delete white spaces.

Co-authored-by: Charles Auguste <charles.auguste@sig.com>
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>