GitLab

* Add R-squared metric, documentation, and tests

* Fix static ci checks: correct Sklearn r2_score URL link, fix cpp linting errors

* Replace non-static data members from pragma reduction with variables

* Update src/metric/metric.cpp

* Add additional asserts, remove needless y.copy()

* Add back y.copy()

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Co-authored-by: James Lamb <jaylamb20@gmail.com>
Co-authored-by: Nikita Titov <nekit94-08@mail.ru>

* add explicit return statement to functions in callback.R

* add explicit return statement to functions in lgb.Booster.R

* add explicit return statement to functions in lgb.Dataset.R

* add explicit return statement to functions in lgb.Predictor.R

* add explicit return statement to functions in lgb.cv.R

* add explicit return statement to functions in lgb.interprete.R

* add explicit return statement to functions in lgb.plot.importance.R

* add explicit return statement to functions in saveRDS.lgb.Booster.R

* add explicit return statement to functions in utils.R

* add explicit return statement to functions in lgb.plot.interpretation.R

* add explicit return statement to functions in build_r.R

* fix typo

* return(self) -> return(invisible(self))

* fix some inconsistent indention

* fix test failure

* add another return() statement

* fix linting errors

* Implement average precision score

* Fix lint errors

* Change name to average_precision

* Add to R-package list of metrics

* Empty commit to trigger CI jobs

* Change name to average_precision

* [R-package] fix issue where early stopping thinks higher MAPE is desirable (fixes #3099)

* fix linting

* only use main metrics

* fix tests