Changes

💡 New Features

• Support deterministic @guolinke (#3494)
• Add support to optimize for NDCG at a given truncation level @metpavel (#3425)
• Add support for cuda version less then 10.0 @shipengfei92 (#3431)
• Updated network retry delay strategy to scale @aakarshg (#3306)
• added new GPU docker files @StrikerRUS (#3408)
• Average precision score @btrotta (#3347)
• Advanced method monotone constraints @CharlesAuguste (#3264)
• Build integrated Python package library @tpboudreau (#3144)
• Add support for CUDA-based GPU @ChipKerchner (#3160)
• [Python] Refactors scikit-learn API to allow a list of evaluation metrics @gramirezespinoza (#3254)
• [R-package] added support for first_metric_only (fixes #2368) @jameslamb (#2912)
• [python][sklearn] be compatible with check_is_fitted sklearn function @StrikerRUS (#3329)

🔨 Breaking

• [python] mark 3.1 version is the last one with Python 2 support @StrikerRUS (#3565)
• bump minimal CMake version @StrikerRUS (#3501)
• [R-package] Remove ability to install precompiled lib_lightgbm (fixes #3320) @jameslamb (#3360)
• [python] Drop Python 3.5 support @StrikerRUS (#3395)

🚀 Efficiency Improvement

• Optimization of row-wise histogram construction @shiyu1994 (#3522)
• Add support to optimize for NDCG at a given truncation level @metpavel (#3425)
• fix address alignment, required by cran @guolinke (#3415)

🐛 Bug Fixes

• [ci] Use different PATH based on Rtools version @jameslamb (#3558)
• [ci] fix CUDA CI builds @StrikerRUS (#3549)
• fix constant hessian for huber objective @guolinke (#3545)
• [R-package] [ci] Fix failures with R 3.6 and CMake (fixes #3469) @jameslamb (#3541)
• [R-package] fix learning-to-rank tests on Solaris @jameslamb (#3534)
• [R-package] fix MM_PREFETCH and MM_MALLOC checks in configure.ac @jameslamb (#3510)
• avoid min_data and min_hessian are zeros at the same time @guolinke (#3492)
• Fix add features @guolinke (#2754)
• remove std::move @StrikerRUS (#3478)
• [ci] [R-package] Fix memory leaks found by valgrind @jameslamb (#3443)
• [R-package] Suppresses unknown pragma warnings during CRAN build @cctechwiz (#3460)
• pin Ubuntu version in distroless docker file @StrikerRUS (#3449)
• Move Tree destructor to header file @lcsdavid (#3417)
• [R-package] miscellaneous changes to comply with CRAN requirements @jameslamb (#3338)
• fix type casting warning @StrikerRUS (#3437)
• [R-package] [ci] Make Windows CI fail if R CMD check fails @jameslamb (#3435)
• [python] Use ctypes for parameters of DLL functions for Dataset @StrikerRUS (#3423)
• Use ctypes to pass parameters (fixes #3398) @btrotta (#3419)
• disable monotone constraint in objective functions with renew_tree_output @guolinke (#3368
• [R-package] Fix incorrect num_iterations, early_stopping_round in saved models (fixes #2208, #2468) @jameslamb (#3368)
• Improve performance of path smoothing @btrotta (#3396)
• fix sparse multiclass local feature contributions and add test @imatiach-msft (#3382)
• Auc mu weights @btrotta (#3349)
• improve subfeature_bynode @guolinke (#3384)
• Fix typo in ResetConfig @btrotta (#3392)
• Avoid segment fault in ResetConfig for GBDT in prediction (fix #3317) @shiyu1994 (#3373)

📖 Documentation

• [docs] simplify RTD config and use latest Sphinx @StrikerRUS (#3554)
• Add note on LightGBM/OpenMP hanging on AWS Batch @cvsmith (#3553)
• Fix #2898: Clearer warning message for user (2^max_depth > num_leaves). @AlbertoEAF (#3537)
• better document for bin_construct_sample_cnt @guolinke (#3521)
• [R-package] [docs] fix broken plots in pkgdown site (fixes #3276) @jameslamb (#3508)
• [docs] added Data Science Bowl Comp Solution 2019 @nabokovas (#3503)
• [docs] fix param docs @StrikerRUS (#3495)
• [docs] update GitHub Actions badge @StrikerRUS (#3446)
• [docs] Change doc link to monotone constraints report to HAL document @CharlesAuguste (#3410)
• [R-package] add new copyright holder in DESCRIPTION @jameslamb (#3409)
• [docs] Simplify the python installation instruction @guolinke (#3378)
• [docs] remove unrelated entry from winning solutions list @StrikerRUS (#3370)
• [python][examples] updated examples with multiple custom metrics @StrikerRUS (#3367)
• [docs] update list of winning solutions in data science competitions @Juniper-23 (#3358)
• [R-package] fix typo in R installation instructions @daviddalpiaz (#3350)

🧰 Maintenance

• fix compilation warning @StrikerRUS (#3564)
• fix warning @guolinke (#3563)
• [R-package] fix install warning @jameslamb (#3552)
• TST make sklearn integration test compatible with 0.24 @glemaitre (#3533)
• move APPLE_OUTPUT_DYLIB option closer to the rest options @StrikerRUS (#3547)
• [ci] simplify R CI scripts @jameslamb (#3535)
• [ci] Make valgrind check stricter @jameslamb (#3536)
• fix invalid read detected by valgrind @guolinke (#3526)
• ignore files from local Dask work @jameslamb (#3527)
• [ci] upgrade GitHub Actions third-party actions to newest versions @jameslamb (#3524)
• [R-package] remove Makefile hack in install.libs.R @jameslamb (#3528)
• [R-package] [ci] add correct path for mingw32-make in CI @jameslamb (#3523)
• [ci] fix check-docs error with AMD support website (fixes #3529) @jameslamb (#3530)
• [R-package] remove unused variables in configure.ac @jameslamb (#3509)
• [R-package] Updated lgb.Booster.R with keyword arguments @Pey-crypto (#3496)
• [ci] automate building CRAN package @jameslamb (#3497)
• [tests][python] remove excess iterations @nabokovas (#3504)
• [ci] Update MacOS version at Travis @nabokovas (#3505)
• [ci] [python] reduce unnecessary data loading in tests @jameslamb (#3486)
• setup CUDA CI job @StrikerRUS (#3424)
• [ci] update SWIG installation on macOS @StrikerRUS (#3477)
• [R-package] Improves logging in lint_r_code.R (fixes #3471) @sinAshish (#3472)
• [R-package] Updated lgb.Predictor.R with keyword arguments @AnshuTrivedi (#3464)
• [ci] ignore R CMD CHECK warnings on new R version @jameslamb (#3468)
• [R-package] remove deprecation warnings on lgb.prepare() functions @jameslamb (#3444)
• [R-package] Updated lgb.train.R with keyword arguments @iadi7ya (#3452)
• [R-package] [ci] Add test on R package with sanitizers @jameslamb (#3439)
• [R-package] add 'cleanup' script to handle left-behind Makevars @jameslamb (#3434)
• [R-package] Update callback.R with keyword arguments @philip-khor (#3430)
• [ci] rename R-package GitHub Actions workflow @StrikerRUS (#3429)
• fix warnings @guolinke (#3399)
• [python] fix dangerous default for eval_at in LGBMRanker @jameslamb (#3377)
• [ci] removed unused environment variable CONDA_ENV @jameslamb (#3411)
• [R-package] use keyword arguments in internal function calls @jameslamb (#3391)
• [R-package] mark CMake option for building R package as private @StrikerRUS (#3397)
• [ci] Use Ubuntu Focal image at Travis @StrikerRUS (#3393)
• [ci] update Boost version @StrikerRUS (#3389)
• [R-package] ignore temp files created by R on Mac @jameslamb (#3388)
• [python] remove unused variable @jameslamb (#3376)
• [R-package] remove unnecessary comments @jameslamb (#3356)
• [ci] host some artifacts needed by R Windows CI jobs @jameslamb (#3359)
• [ci] remove Azure checks from R CI @jameslamb (#3355)
• [ci] add an allgood job for easy [required] builds @graingert (#3351)
• bump version @guolinke (#3344)