GitLab

* Fix index out-of-range exception generated by BaggingHelper on small datasets.

Prior to this change, the line "score_t threshold = tmp_gradients[top_k - 1];" would generate an exception, since tmp_gradients would be empty when the cnt input value to the function is zero.

* Update goss.hpp

* Update goss.hpp

* Add API method LGBM_BoosterPredictForMats which runs prediction on a data set given as of array of pointers to rows (as opposed to existing method LGBM_BoosterPredictForMat which requires data given as contiguous array)

* Fix incorrect upstream merge

* Add link to LightGBM.NET

* Fix indenting to 2 spaces

* Dummy edit to trigger CI

* Dummy edit to trigger CI

* remove duplicate functions from merge

* Fix for CreatePredictor function: for VS2017 in Debug build, the previous version would end up giving an uninitialised prediction function that would throw access violation exceptions when invoked.
Co-authored-by: matthew-peacock <matthew.peacock@whiteoakam.com>
Co-authored-by: Guolin Ke <guolin.ke@outlook.com>

Approximately %80 of runtime when loading "low column count, high row
count" DataFrames into Datasets is consumed in `np.fromiter`, called
as part of the `Dataset.get_field` method.

This is particularly pernicious hotspot, as unlike other ctypes-based
methods this is a hot loop over a python iterator loop and causes
significant GIL-contention in multi-threaded applications.

Replace `np.fromiter` with a direct call to `np.ctypeslib.as_array`,
which allows a single-shot `copy` of the underlying array.

This reduces the load time of a ~35 million row categorical dataframe
with 1 column from ~5 seconds to ~1 second, and allows multi-threaded
execution.

* Update setup.sh

* Update test.sh

* Update test_dask.py

* Update test_engine.py

* Update .vsts-ci.yml

* run isort in CI linting job

* workaround conda compatibility issues

* minor mypy type errors fixed

* fix some warnings from mypy

* fix 3 mypy warnings

* selectively ignored some mypy errors

* minor mypy type errors fixed

* minor mypy type errors fixed

* minor mypy type errors fixed

* added import

* Update python-package/lightgbm/callback.py

* Apply suggestions from code review

* Apply suggestions from code review
Co-authored-by: James Lamb <jaylamb20@gmail.com>
Co-authored-by: James Lamb <jaylamb20@gmail.com>

* Update docs about linear tree and monotone constraints

* Fix punctuation

* openmp_wrapper.h stubs signature use __GOMP_NOTHROW

Fix #3915. OpenMP stubs do not use the noexcept attibute which is present in the gcc version of openmp, and which trigger compilation errors as seen below. dmlc-core uses the same technique and macro.

/usr/lib/gcc/x86_64-linux-gnu/9/include/omp.h:114:12: error: declaration of ‘int omp_get_thread_num() noexcept’ has a different exception specifier
  114 | extern int omp_get_thread_num (void) __GOMP_NOTHROW;
      |            ^~~~~~~~~~~~~~~~~~
...
xxx/include/LightGBM/utils/openmp_wrapper.h:81:14: note: from previous declaration ‘int omp_get_thread_num()’
   81 |   inline int omp_get_thread_num() {return 0;}
      |              ^~~~~~~~~~~~~~~~~~

* move __GOMP_NOTHROW definition in the no open mp stub conditional branch

* Update include/LightGBM/utils/openmp_wrapper.h

Yes make sense, just changed it
Co-authored-by: James Lamb <jaylamb20@gmail.com>

* add NOLINT macro to disable cpplint on a safe line of code
Co-authored-by: James Lamb <jaylamb20@gmail.com>

Fix access violation exception that can occur during invocation of loop lambda function when inner_start >= inner_end in 'For' template (#3936)

* Fix index out-of-range exception generated by BaggingHelper on small datasets.

Prior to this change, the line "score_t threshold = tmp_gradients[top_k - 1];" would generate an exception, since tmp_gradients would be empty when the cnt input value to the function is zero.

* Update goss.hpp

* Update goss.hpp

* Add API method LGBM_BoosterPredictForMats which runs prediction on a data set given as of array of pointers to rows (as opposed to existing method LGBM_BoosterPredictForMat which requires data given as contiguous array)

* Fix incorrect upstream merge

* Add link to LightGBM.NET

* Fix indenting to 2 spaces

* Dummy edit to trigger CI

* Dummy edit to trigger CI

* remove duplicate functions from merge

* Fix access violation exception that can occur during invocation of loop lambda function when inner_start >= inner_end in 'For' template.

In particular, this can occur in Tree::AddPredictionToScore on line 291 where the loop lambda function body (created by the PredictionFun macro) dereferences used_data_indices[start].

For reference, the particular case which triggered this exception in my case was:
  * start = 0
  * end = 93,203
  * n_block = 56
  * min_block_size = 512
for which the BlockInfo method gave:
  * n_block = 56
  * num_inner = 1,696
and so, for the case i=55 (i.e., the last case in the loop), we get
  * inner_start = start + num_inner * i
                = 93,280
which is greater than 'end' and hence triggers the exception.

* Change formatting of proposed modification
Co-authored-by: matthew-peacock <matthew.peacock@whiteoakam.com>
Co-authored-by: Guolin Ke <guolin.ke@outlook.com>

* Update dask.py

* Update sklearn.py