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.. include:: _contributors.rst
.. currentmodule:: sklearn
.. _release_notes_0_23:
============
Version 0.23
============
For a short description of the main highlights of the release, please refer to
:ref:`sphx_glr_auto_examples_release_highlights_plot_release_highlights_0_23_0.py`.
.. include:: changelog_legend.inc
.. _changes_0_23_2:
Version 0.23.2
==============
Changed models
--------------
The following estimators and functions, when fit with the same data and
parameters, may produce different models from the previous version. This often
occurs due to changes in the modelling logic (bug fixes or enhancements), or in
random sampling procedures.
- |Fix| ``inertia_`` attribute of :class:`cluster.KMeans` and
:class:`cluster.MiniBatchKMeans`.
Details are listed in the changelog below.
(While we are trying to better inform users by providing this information, we
cannot assure that this list is complete.)
Changelog
---------
:mod:`sklearn.cluster`
......................
- |Fix| Fixed a bug in :class:`cluster.KMeans` where rounding errors could
prevent convergence to be declared when `tol=0`. :pr:`17959` by
:user:`Jérémie du Boisberranger <jeremiedbb>`.
- |Fix| Fixed a bug in :class:`cluster.KMeans` and
:class:`cluster.MiniBatchKMeans` where the reported inertia was incorrectly
weighted by the sample weights. :pr:`17848` by
:user:`Jérémie du Boisberranger <jeremiedbb>`.
- |Fix| Fixed a bug in :class:`cluster.MeanShift` with `bin_seeding=True`. When
the estimated bandwidth is 0, the behavior is equivalent to
`bin_seeding=False`.
:pr:`17742` by :user:`Jeremie du Boisberranger <jeremiedbb>`.
- |Fix| Fixed a bug in :class:`cluster.AffinityPropagation`, that
gives incorrect clusters when the array dtype is float32.
:pr:`17995` by :user:`Thomaz Santana <Wikilicious>` and
:user:`Amanda Dsouza <amy12xx>`.
:mod:`sklearn.decomposition`
............................
- |Fix| Fixed a bug in
:func:`decomposition.MiniBatchDictionaryLearning.partial_fit` which should
update the dictionary by iterating only once over a mini-batch.
:pr:`17433` by :user:`Chiara Marmo <cmarmo>`.
- |Fix| Avoid overflows on Windows in
:func:`decomposition.IncrementalPCA.partial_fit` for large ``batch_size`` and
``n_samples`` values.
:pr:`17985` by :user:`Alan Butler <aldee153>` and
:user:`Amanda Dsouza <amy12xx>`.
:mod:`sklearn.ensemble`
.......................
- |Fix| Fixed bug in `ensemble.MultinomialDeviance` where the
average of logloss was incorrectly calculated as sum of logloss.
:pr:`17694` by :user:`Markus Rempfler <rempfler>` and
:user:`Tsutomu Kusanagi <t-kusanagi2>`.
- |Fix| Fixes :class:`ensemble.StackingClassifier` and
:class:`ensemble.StackingRegressor` compatibility with estimators that
do not define `n_features_in_`. :pr:`17357` by `Thomas Fan`_.
:mod:`sklearn.feature_extraction`
.................................
- |Fix| Fixes bug in :class:`feature_extraction.text.CountVectorizer` where
sample order invariance was broken when `max_features` was set and features
had the same count. :pr:`18016` by `Thomas Fan`_, `Roman Yurchak`_, and
`Joel Nothman`_.
:mod:`sklearn.linear_model`
...........................
- |Fix| :func:`linear_model.lars_path` does not overwrite `X` when
`X_copy=True` and `Gram='auto'`. :pr:`17914` by `Thomas Fan`_.
:mod:`sklearn.manifold`
.......................
- |Fix| Fixed a bug where :func:`metrics.pairwise_distances` would raise an
error if ``metric='seuclidean'`` and ``X`` is not type ``np.float64``.
:pr:`15730` by :user:`Forrest Koch <ForrestCKoch>`.
:mod:`sklearn.metrics`
......................
- |Fix| Fixed a bug in :func:`metrics.mean_squared_error` where the
average of multiple RMSE values was incorrectly calculated as the root of the
average of multiple MSE values.
:pr:`17309` by :user:`Swier Heeres <swierh>`.
:mod:`sklearn.pipeline`
.......................
- |Fix| :class:`pipeline.FeatureUnion` raises a deprecation warning when
`None` is included in `transformer_list`. :pr:`17360` by `Thomas Fan`_.
:mod:`sklearn.utils`
....................
- |Fix| Fix :func:`utils.estimator_checks.check_estimator` so that all test
cases support the `binary_only` estimator tag.
:pr:`17812` by :user:`Bruno Charron <brcharron>`.
.. _changes_0_23_1:
Version 0.23.1
==============
**May 18 2020**
Changelog
---------
:mod:`sklearn.cluster`
......................
- |Efficiency| :class:`cluster.KMeans` efficiency has been improved for very
small datasets. In particular it cannot spawn idle threads any more.
:pr:`17210` and :pr:`17235` by :user:`Jeremie du Boisberranger <jeremiedbb>`.
- |Fix| Fixed a bug in :class:`cluster.KMeans` where the sample weights
provided by the user were modified in place. :pr:`17204` by
:user:`Jeremie du Boisberranger <jeremiedbb>`.
Miscellaneous
.............
- |Fix| Fixed a bug in the `repr` of third-party estimators that use a
`**kwargs` parameter in their constructor, when `changed_only` is True
which is now the default. :pr:`17205` by `Nicolas Hug`_.
.. _changes_0_23:
Version 0.23.0
==============
**May 12 2020**
Enforcing keyword-only arguments
--------------------------------
In an effort to promote clear and non-ambiguous use of the library, most
constructor and function parameters are now expected to be passed as keyword
arguments (i.e. using the `param=value` syntax) instead of positional. To
ease the transition, a `FutureWarning` is raised if a keyword-only parameter
is used as positional. In version 1.0 (renaming of 0.25), these parameters
will be strictly keyword-only, and a `TypeError` will be raised.
:issue:`15005` by `Joel Nothman`_, `Adrin Jalali`_, `Thomas Fan`_, and
`Nicolas Hug`_. See `SLEP009
<https://scikit-learn-enhancement-proposals.readthedocs.io/en/latest/slep009/proposal.html>`_
for more details.
Changed models
--------------
The following estimators and functions, when fit with the same data and
parameters, may produce different models from the previous version. This often
occurs due to changes in the modelling logic (bug fixes or enhancements), or in
random sampling procedures.
- |Fix| :class:`ensemble.BaggingClassifier`, :class:`ensemble.BaggingRegressor`,
and :class:`ensemble.IsolationForest`.
- |Fix| :class:`cluster.KMeans` with ``algorithm="elkan"`` and
``algorithm="full"``.
- |Fix| :class:`cluster.Birch`
- |Fix| `compose.ColumnTransformer.get_feature_names`
- |Fix| :func:`compose.ColumnTransformer.fit`
- |Fix| :func:`datasets.make_multilabel_classification`
- |Fix| :class:`decomposition.PCA` with `n_components='mle'`
- |Enhancement| :class:`decomposition.NMF` and
:func:`decomposition.non_negative_factorization` with float32 dtype input.
- |Fix| :func:`decomposition.KernelPCA.inverse_transform`
- |API| :class:`ensemble.HistGradientBoostingClassifier` and
:class:`ensemble.HistGradientBoostingRegressor`
- |Fix| ``estimator_samples_`` in :class:`ensemble.BaggingClassifier`,
:class:`ensemble.BaggingRegressor` and :class:`ensemble.IsolationForest`
- |Fix| :class:`ensemble.StackingClassifier` and
:class:`ensemble.StackingRegressor` with `sample_weight`
- |Fix| :class:`gaussian_process.GaussianProcessRegressor`
- |Fix| :class:`linear_model.RANSACRegressor` with ``sample_weight``.
- |Fix| :class:`linear_model.RidgeClassifierCV`
- |Fix| :func:`metrics.mean_squared_error` with `squared` and
`multioutput='raw_values'`.
- |Fix| :func:`metrics.mutual_info_score` with negative scores.
- |Fix| :func:`metrics.confusion_matrix` with zero length `y_true` and `y_pred`
- |Fix| :class:`neural_network.MLPClassifier`
- |Fix| :class:`preprocessing.StandardScaler` with `partial_fit` and sparse
input.
- |Fix| :class:`preprocessing.Normalizer` with norm='max'
- |Fix| Any model using the `svm.libsvm` or the `svm.liblinear` solver,
including :class:`svm.LinearSVC`, :class:`svm.LinearSVR`,
:class:`svm.NuSVC`, :class:`svm.NuSVR`, :class:`svm.OneClassSVM`,
:class:`svm.SVC`, :class:`svm.SVR`, :class:`linear_model.LogisticRegression`.
- |Fix| :class:`tree.DecisionTreeClassifier`, :class:`tree.ExtraTreeClassifier` and
:class:`ensemble.GradientBoostingClassifier` as well as ``predict`` method of
:class:`tree.DecisionTreeRegressor`, :class:`tree.ExtraTreeRegressor`, and
:class:`ensemble.GradientBoostingRegressor` and read-only float32 input in
``predict``, ``decision_path`` and ``predict_proba``.
Details are listed in the changelog below.
(While we are trying to better inform users by providing this information, we
cannot assure that this list is complete.)
Changelog
---------
..
Entries should be grouped by module (in alphabetic order) and prefixed with
one of the labels: |MajorFeature|, |Feature|, |Efficiency|, |Enhancement|,
|Fix| or |API| (see whats_new.rst for descriptions).
Entries should be ordered by those labels (e.g. |Fix| after |Efficiency|).
Changes not specific to a module should be listed under *Multiple Modules*
or *Miscellaneous*.
Entries should end with:
:pr:`123456` by :user:`Joe Bloggs <joeongithub>`.
where 123456 is the *pull request* number, not the issue number.
:mod:`sklearn.cluster`
......................
- |Efficiency| :class:`cluster.Birch` implementation of the predict method
avoids high memory footprint by calculating the distances matrix using
a chunked scheme.
:pr:`16149` by :user:`Jeremie du Boisberranger <jeremiedbb>` and
:user:`Alex Shacked <alexshacked>`.
- |Efficiency| |MajorFeature| The critical parts of :class:`cluster.KMeans`
have a more optimized implementation. Parallelism is now over the data
instead of over initializations allowing better scalability. :pr:`11950` by
:user:`Jeremie du Boisberranger <jeremiedbb>`.
- |Enhancement| :class:`cluster.KMeans` now supports sparse data when
`solver = "elkan"`. :pr:`11950` by
:user:`Jeremie du Boisberranger <jeremiedbb>`.
- |Enhancement| :class:`cluster.AgglomerativeClustering` has a faster and more
memory efficient implementation of single linkage clustering.
:pr:`11514` by :user:`Leland McInnes <lmcinnes>`.
- |Fix| :class:`cluster.KMeans` with ``algorithm="elkan"`` now converges with
``tol=0`` as with the default ``algorithm="full"``. :pr:`16075` by
:user:`Erich Schubert <kno10>`.
- |Fix| Fixed a bug in :class:`cluster.Birch` where the `n_clusters` parameter
could not have a `np.int64` type. :pr:`16484`
by :user:`Jeremie du Boisberranger <jeremiedbb>`.
- |Fix| :class:`cluster.AgglomerativeClustering` add specific error when
distance matrix is not square and `affinity=precomputed`.
:pr:`16257` by :user:`Simona Maggio <simonamaggio>`.
- |API| The ``n_jobs`` parameter of :class:`cluster.KMeans`,
:class:`cluster.SpectralCoclustering` and
:class:`cluster.SpectralBiclustering` is deprecated. They now use OpenMP
based parallelism. For more details on how to control the number of threads,
please refer to our :ref:`parallelism` notes. :pr:`11950` by
:user:`Jeremie du Boisberranger <jeremiedbb>`.
- |API| The ``precompute_distances`` parameter of :class:`cluster.KMeans` is
deprecated. It has no effect. :pr:`11950` by
:user:`Jeremie du Boisberranger <jeremiedbb>`.
- |API| The ``random_state`` parameter has been added to
:class:`cluster.AffinityPropagation`. :pr:`16801` by :user:`rcwoolston`
and :user:`Chiara Marmo <cmarmo>`.
:mod:`sklearn.compose`
......................
- |Efficiency| :class:`compose.ColumnTransformer` is now faster when working
with dataframes and strings are used to specific subsets of data for
transformers. :pr:`16431` by `Thomas Fan`_.
- |Enhancement| :class:`compose.ColumnTransformer` method ``get_feature_names``
now supports `'passthrough'` columns, with the feature name being either
the column name for a dataframe, or `'xi'` for column index `i`.
:pr:`14048` by :user:`Lewis Ball <lrjball>`.
- |Fix| :class:`compose.ColumnTransformer` method ``get_feature_names`` now
returns correct results when one of the transformer steps applies on an
empty list of columns :pr:`15963` by `Roman Yurchak`_.
- |Fix| :func:`compose.ColumnTransformer.fit` will error when selecting
a column name that is not unique in the dataframe. :pr:`16431` by
`Thomas Fan`_.
:mod:`sklearn.datasets`
.......................
- |Efficiency| :func:`datasets.fetch_openml` has reduced memory usage because
it no longer stores the full dataset text stream in memory. :pr:`16084` by
`Joel Nothman`_.
- |Feature| :func:`datasets.fetch_california_housing` now supports
heterogeneous data using pandas by setting `as_frame=True`. :pr:`15950`
by :user:`Stephanie Andrews <gitsteph>` and
:user:`Reshama Shaikh <reshamas>`.
- |Feature| embedded dataset loaders :func:`datasets.load_breast_cancer`,
:func:`datasets.load_diabetes`, :func:`datasets.load_digits`,
:func:`datasets.load_iris`, :func:`datasets.load_linnerud` and
:func:`datasets.load_wine` now support loading as a pandas ``DataFrame`` by
setting `as_frame=True`. :pr:`15980` by :user:`wconnell` and
:user:`Reshama Shaikh <reshamas>`.
- |Enhancement| Added ``return_centers`` parameter in
:func:`datasets.make_blobs`, which can be used to return
centers for each cluster.
:pr:`15709` by :user:`shivamgargsya` and
:user:`Venkatachalam N <venkyyuvy>`.
- |Enhancement| Functions :func:`datasets.make_circles` and
:func:`datasets.make_moons` now accept two-element tuple.
:pr:`15707` by :user:`Maciej J Mikulski <mjmikulski>`.
- |Fix| :func:`datasets.make_multilabel_classification` now generates
`ValueError` for arguments `n_classes < 1` OR `length < 1`.
:pr:`16006` by :user:`Rushabh Vasani <rushabh-v>`.
- |API| The `StreamHandler` was removed from `sklearn.logger` to avoid
double logging of messages in common cases where a handler is attached
to the root logger, and to follow the Python logging documentation
recommendation for libraries to leave the log message handling to
users and application code. :pr:`16451` by :user:`Christoph Deil <cdeil>`.
:mod:`sklearn.decomposition`
............................
- |Enhancement| :class:`decomposition.NMF` and
:func:`decomposition.non_negative_factorization` now preserves float32 dtype.
:pr:`16280` by :user:`Jeremie du Boisberranger <jeremiedbb>`.
- |Enhancement| :func:`decomposition.TruncatedSVD.transform` is now faster on
given sparse ``csc`` matrices. :pr:`16837` by :user:`wornbb`.
- |Fix| :class:`decomposition.PCA` with a float `n_components` parameter, will
exclusively choose the components that explain the variance greater than
`n_components`. :pr:`15669` by :user:`Krishna Chaitanya <krishnachaitanya9>`
- |Fix| :class:`decomposition.PCA` with `n_components='mle'` now correctly
handles small eigenvalues, and does not infer 0 as the correct number of
components. :pr:`16224` by :user:`Lisa Schwetlick <lschwetlick>`, and
:user:`Gelavizh Ahmadi <gelavizh1>` and :user:`Marija Vlajic Wheeler
<marijavlajic>` and :pr:`16841` by `Nicolas Hug`_.
- |Fix| :class:`decomposition.KernelPCA` method ``inverse_transform`` now
applies the correct inverse transform to the transformed data. :pr:`16655`
by :user:`Lewis Ball <lrjball>`.
- |Fix| Fixed bug that was causing :class:`decomposition.KernelPCA` to sometimes
raise `invalid value encountered in multiply` during `fit`.
:pr:`16718` by :user:`Gui Miotto <gui-miotto>`.
- |Feature| Added `n_components_` attribute to :class:`decomposition.SparsePCA`
and :class:`decomposition.MiniBatchSparsePCA`. :pr:`16981` by
:user:`Mateusz Górski <Reksbril>`.
:mod:`sklearn.ensemble`
.......................
- |MajorFeature| :class:`ensemble.HistGradientBoostingClassifier` and
:class:`ensemble.HistGradientBoostingRegressor` now support
:term:`sample_weight`. :pr:`14696` by `Adrin Jalali`_ and `Nicolas Hug`_.
- |Feature| Early stopping in
:class:`ensemble.HistGradientBoostingClassifier` and
:class:`ensemble.HistGradientBoostingRegressor` is now determined with a
new `early_stopping` parameter instead of `n_iter_no_change`. Default value
is 'auto', which enables early stopping if there are at least 10,000
samples in the training set. :pr:`14516` by :user:`Johann Faouzi
<johannfaouzi>`.
- |MajorFeature| :class:`ensemble.HistGradientBoostingClassifier` and
:class:`ensemble.HistGradientBoostingRegressor` now support monotonic
constraints, useful when features are supposed to have a positive/negative
effect on the target. :pr:`15582` by `Nicolas Hug`_.
- |API| Added boolean `verbose` flag to classes:
:class:`ensemble.VotingClassifier` and :class:`ensemble.VotingRegressor`.
:pr:`16069` by :user:`Sam Bail <spbail>`,
:user:`Hanna Bruce MacDonald <hannahbrucemacdonald>`,
:user:`Reshama Shaikh <reshamas>`, and
:user:`Chiara Marmo <cmarmo>`.
- |API| Fixed a bug in :class:`ensemble.HistGradientBoostingClassifier` and
:class:`ensemble.HistGradientBoostingRegressor` that would not respect the
`max_leaf_nodes` parameter if the criteria was reached at the same time as
the `max_depth` criteria. :pr:`16183` by `Nicolas Hug`_.
- |Fix| Changed the convention for `max_depth` parameter of
:class:`ensemble.HistGradientBoostingClassifier` and
:class:`ensemble.HistGradientBoostingRegressor`. The depth now corresponds to
the number of edges to go from the root to the deepest leaf.
Stumps (trees with one split) are now allowed.
:pr:`16182` by :user:`Santhosh B <santhoshbala18>`
- |Fix| Fixed a bug in :class:`ensemble.BaggingClassifier`,
:class:`ensemble.BaggingRegressor` and :class:`ensemble.IsolationForest`
where the attribute `estimators_samples_` did not generate the proper indices
used during `fit`.
:pr:`16437` by :user:`Jin-Hwan CHO <chofchof>`.
- |Fix| Fixed a bug in :class:`ensemble.StackingClassifier` and
:class:`ensemble.StackingRegressor` where the `sample_weight`
argument was not being passed to `cross_val_predict` when
evaluating the base estimators on cross-validation folds
to obtain the input to the meta estimator.
:pr:`16539` by :user:`Bill DeRose <wderose>`.
- |Feature| Added additional option `loss="poisson"` to
:class:`ensemble.HistGradientBoostingRegressor`, which adds Poisson deviance
with log-link useful for modeling count data.
:pr:`16692` by :user:`Christian Lorentzen <lorentzenchr>`
- |Fix| Fixed a bug where :class:`ensemble.HistGradientBoostingRegressor` and
:class:`ensemble.HistGradientBoostingClassifier` would fail with multiple
calls to fit when `warm_start=True`, `early_stopping=True`, and there is no
validation set. :pr:`16663` by `Thomas Fan`_.
:mod:`sklearn.feature_extraction`
.................................
- |Efficiency| :class:`feature_extraction.text.CountVectorizer` now sorts
features after pruning them by document frequency. This improves performances
for datasets with large vocabularies combined with ``min_df`` or ``max_df``.
:pr:`15834` by :user:`Santiago M. Mola <smola>`.
:mod:`sklearn.feature_selection`
................................
- |Enhancement| Added support for multioutput data in
:class:`feature_selection.RFE` and :class:`feature_selection.RFECV`.
:pr:`16103` by :user:`Divyaprabha M <divyaprabha123>`.
- |API| Adds :class:`feature_selection.SelectorMixin` back to public API.
:pr:`16132` by :user:`trimeta`.
:mod:`sklearn.gaussian_process`
...............................
- |Enhancement| :func:`gaussian_process.kernels.Matern` returns the RBF kernel when ``nu=np.inf``.
:pr:`15503` by :user:`Sam Dixon <sam-dixon>`.
- |Fix| Fixed bug in :class:`gaussian_process.GaussianProcessRegressor` that
caused predicted standard deviations to only be between 0 and 1 when
WhiteKernel is not used. :pr:`15782`
by :user:`plgreenLIRU`.
:mod:`sklearn.impute`
.....................
- |Enhancement| :class:`impute.IterativeImputer` accepts both scalar and array-like inputs for
``max_value`` and ``min_value``. Array-like inputs allow a different max and min to be specified
for each feature. :pr:`16403` by :user:`Narendra Mukherjee <narendramukherjee>`.
- |Enhancement| :class:`impute.SimpleImputer`, :class:`impute.KNNImputer`, and
:class:`impute.IterativeImputer` accepts pandas' nullable integer dtype with
missing values. :pr:`16508` by `Thomas Fan`_.
:mod:`sklearn.inspection`
.........................
- |Feature| :func:`inspection.partial_dependence` and
`inspection.plot_partial_dependence` now support the fast 'recursion'
method for :class:`ensemble.RandomForestRegressor` and
:class:`tree.DecisionTreeRegressor`. :pr:`15864` by
`Nicolas Hug`_.
:mod:`sklearn.linear_model`
...........................
- |MajorFeature| Added generalized linear models (GLM) with non normal error
distributions, including :class:`linear_model.PoissonRegressor`,
:class:`linear_model.GammaRegressor` and :class:`linear_model.TweedieRegressor`
which use Poisson, Gamma and Tweedie distributions respectively.
:pr:`14300` by :user:`Christian Lorentzen <lorentzenchr>`, `Roman Yurchak`_,
and `Olivier Grisel`_.
- |MajorFeature| Support of `sample_weight` in
:class:`linear_model.ElasticNet` and :class:`linear_model.Lasso` for dense
feature matrix `X`. :pr:`15436` by :user:`Christian Lorentzen
<lorentzenchr>`.
- |Efficiency| :class:`linear_model.RidgeCV` and
:class:`linear_model.RidgeClassifierCV` now does not allocate a
potentially large array to store dual coefficients for all hyperparameters
during its `fit`, nor an array to store all error or LOO predictions unless
`store_cv_values` is `True`.
:pr:`15652` by :user:`Jérôme Dockès <jeromedockes>`.
- |Enhancement| :class:`linear_model.LassoLars` and
:class:`linear_model.Lars` now support a `jitter` parameter that adds
random noise to the target. This might help with stability in some edge
cases. :pr:`15179` by :user:`angelaambroz`.
- |Fix| Fixed a bug where if a `sample_weight` parameter was passed to the fit
method of :class:`linear_model.RANSACRegressor`, it would not be passed to
the wrapped `base_estimator` during the fitting of the final model.
:pr:`15773` by :user:`Jeremy Alexandre <J-A16>`.
- |Fix| Add `best_score_` attribute to :class:`linear_model.RidgeCV` and
:class:`linear_model.RidgeClassifierCV`.
:pr:`15655` by :user:`Jérôme Dockès <jeromedockes>`.
- |Fix| Fixed a bug in :class:`linear_model.RidgeClassifierCV` to pass a
specific scoring strategy. Before the internal estimator outputs score
instead of predictions.
:pr:`14848` by :user:`Venkatachalam N <venkyyuvy>`.
- |Fix| :class:`linear_model.LogisticRegression` will now avoid an unnecessary
iteration when `solver='newton-cg'` by checking for inferior or equal instead
of strictly inferior for maximum of `absgrad` and `tol` in `utils.optimize._newton_cg`.
:pr:`16266` by :user:`Rushabh Vasani <rushabh-v>`.
- |API| Deprecated public attributes `standard_coef_`, `standard_intercept_`,
`average_coef_`, and `average_intercept_` in
:class:`linear_model.SGDClassifier`,
:class:`linear_model.SGDRegressor`,
:class:`linear_model.PassiveAggressiveClassifier`,
:class:`linear_model.PassiveAggressiveRegressor`.
:pr:`16261` by :user:`Carlos Brandt <chbrandt>`.
- |Fix| |Efficiency| :class:`linear_model.ARDRegression` is more stable and
much faster when `n_samples > n_features`. It can now scale to hundreds of
thousands of samples. The stability fix might imply changes in the number
of non-zero coefficients and in the predicted output. :pr:`16849` by
`Nicolas Hug`_.
- |Fix| Fixed a bug in :class:`linear_model.ElasticNetCV`,
:class:`linear_model.MultiTaskElasticNetCV`, :class:`linear_model.LassoCV`
and :class:`linear_model.MultiTaskLassoCV` where fitting would fail when
using joblib loky backend. :pr:`14264` by
:user:`Jérémie du Boisberranger <jeremiedbb>`.
- |Efficiency| Speed up :class:`linear_model.MultiTaskLasso`,
:class:`linear_model.MultiTaskLassoCV`, :class:`linear_model.MultiTaskElasticNet`,
:class:`linear_model.MultiTaskElasticNetCV` by avoiding slower
BLAS Level 2 calls on small arrays
:pr:`17021` by :user:`Alex Gramfort <agramfort>` and
:user:`Mathurin Massias <mathurinm>`.
:mod:`sklearn.metrics`
......................
- |Enhancement| :func:`metrics.pairwise_distances_chunked` now allows
its ``reduce_func`` to not have a return value, enabling in-place operations.
:pr:`16397` by `Joel Nothman`_.
- |Fix| Fixed a bug in :func:`metrics.mean_squared_error` to not ignore
argument `squared` when argument `multioutput='raw_values'`.
:pr:`16323` by :user:`Rushabh Vasani <rushabh-v>`
- |Fix| Fixed a bug in :func:`metrics.mutual_info_score` where negative
scores could be returned. :pr:`16362` by `Thomas Fan`_.
- |Fix| Fixed a bug in :func:`metrics.confusion_matrix` that would raise
an error when `y_true` and `y_pred` were length zero and `labels` was
not `None`. In addition, we raise an error when an empty list is given to
the `labels` parameter.
:pr:`16442` by :user:`Kyle Parsons <parsons-kyle-89>`.
- |API| Changed the formatting of values in
:meth:`metrics.ConfusionMatrixDisplay.plot` and
`metrics.plot_confusion_matrix` to pick the shorter format (either '2g'
or 'd'). :pr:`16159` by :user:`Rick Mackenbach <Rick-Mackenbach>` and
`Thomas Fan`_.
- |API| From version 0.25, :func:`metrics.pairwise_distances` will no
longer automatically compute the ``VI`` parameter for Mahalanobis distance
and the ``V`` parameter for seuclidean distance if ``Y`` is passed. The user
will be expected to compute this parameter on the training data of their
choice and pass it to `pairwise_distances`. :pr:`16993` by `Joel Nothman`_.
:mod:`sklearn.model_selection`
..............................
- |Enhancement| :class:`model_selection.GridSearchCV` and
:class:`model_selection.RandomizedSearchCV` yields stack trace information
in fit failed warning messages in addition to previously emitted
type and details.
:pr:`15622` by :user:`Gregory Morse <GregoryMorse>`.
- |Fix| :func:`model_selection.cross_val_predict` supports
`method="predict_proba"` when `y=None`. :pr:`15918` by
:user:`Luca Kubin <lkubin>`.
- |Fix| `model_selection.fit_grid_point` is deprecated in 0.23 and will
be removed in 0.25. :pr:`16401` by
:user:`Arie Pratama Sutiono <ariepratama>`
:mod:`sklearn.multioutput`
..........................
- |Feature| :func:`multioutput.MultiOutputRegressor.fit` and
:func:`multioutput.MultiOutputClassifier.fit` now can accept `fit_params`
to pass to the `estimator.fit` method of each step. :issue:`15953`
:pr:`15959` by :user:`Ke Huang <huangk10>`.
- |Enhancement| :class:`multioutput.RegressorChain` now supports `fit_params`
for `base_estimator` during `fit`.
:pr:`16111` by :user:`Venkatachalam N <venkyyuvy>`.
:mod:`sklearn.naive_bayes`
.............................
- |Fix| A correctly formatted error message is shown in
:class:`naive_bayes.CategoricalNB` when the number of features in the input
differs between `predict` and `fit`.
:pr:`16090` by :user:`Madhura Jayaratne <madhuracj>`.
:mod:`sklearn.neural_network`
.............................
- |Efficiency| :class:`neural_network.MLPClassifier` and
:class:`neural_network.MLPRegressor` has reduced memory footprint when using
stochastic solvers, `'sgd'` or `'adam'`, and `shuffle=True`. :pr:`14075` by
:user:`meyer89`.
- |Fix| Increases the numerical stability of the logistic loss function in
:class:`neural_network.MLPClassifier` by clipping the probabilities.
:pr:`16117` by `Thomas Fan`_.
:mod:`sklearn.inspection`
.........................
- |Enhancement| :class:`inspection.PartialDependenceDisplay` now exposes the
deciles lines as attributes so they can be hidden or customized. :pr:`15785`
by `Nicolas Hug`_
:mod:`sklearn.preprocessing`
............................
- |Feature| argument `drop` of :class:`preprocessing.OneHotEncoder`
will now accept value 'if_binary' and will drop the first category of
each feature with two categories. :pr:`16245`
by :user:`Rushabh Vasani <rushabh-v>`.
- |Enhancement| :class:`preprocessing.OneHotEncoder`'s `drop_idx_` ndarray
can now contain `None`, where `drop_idx_[i] = None` means that no category
is dropped for index `i`. :pr:`16585` by :user:`Chiara Marmo <cmarmo>`.
- |Enhancement| :class:`preprocessing.MaxAbsScaler`,
:class:`preprocessing.MinMaxScaler`, :class:`preprocessing.StandardScaler`,
:class:`preprocessing.PowerTransformer`,
:class:`preprocessing.QuantileTransformer`,
:class:`preprocessing.RobustScaler` now supports pandas' nullable integer
dtype with missing values. :pr:`16508` by `Thomas Fan`_.
- |Efficiency| :class:`preprocessing.OneHotEncoder` is now faster at
transforming. :pr:`15762` by `Thomas Fan`_.
- |Fix| Fix a bug in :class:`preprocessing.StandardScaler` which was incorrectly
computing statistics when calling `partial_fit` on sparse inputs.
:pr:`16466` by :user:`Guillaume Lemaitre <glemaitre>`.
- |Fix| Fix a bug in :class:`preprocessing.Normalizer` with norm='max',
which was not taking the absolute value of the maximum values before
normalizing the vectors. :pr:`16632` by
:user:`Maura Pintor <Maupin1991>` and :user:`Battista Biggio <bbiggio>`.
:mod:`sklearn.semi_supervised`
..............................
- |Fix| :class:`semi_supervised.LabelSpreading` and
:class:`semi_supervised.LabelPropagation` avoids divide by zero warnings
when normalizing `label_distributions_`. :pr:`15946` by :user:`ngshya`.
:mod:`sklearn.svm`
..................
- |Fix| |Efficiency| Improved ``libsvm`` and ``liblinear`` random number
generators used to randomly select coordinates in the coordinate descent
algorithms. Platform-dependent C ``rand()`` was used, which is only able to
generate numbers up to ``32767`` on windows platform (see this `blog
post <https://codeforces.com/blog/entry/61587>`_) and also has poor
randomization power as suggested by `this presentation
<https://channel9.msdn.com/Events/GoingNative/2013/rand-Considered-Harmful>`_.
It was replaced with C++11 ``mt19937``, a Mersenne Twister that correctly
generates 31bits/63bits random numbers on all platforms. In addition, the
crude "modulo" postprocessor used to get a random number in a bounded
interval was replaced by the tweaked Lemire method as suggested by `this blog
post <http://www.pcg-random.org/posts/bounded-rands.html>`_.
Any model using the `svm.libsvm` or the `svm.liblinear` solver,
including :class:`svm.LinearSVC`, :class:`svm.LinearSVR`,
:class:`svm.NuSVC`, :class:`svm.NuSVR`, :class:`svm.OneClassSVM`,
:class:`svm.SVC`, :class:`svm.SVR`, :class:`linear_model.LogisticRegression`,
is affected. In particular users can expect a better convergence when the
number of samples (LibSVM) or the number of features (LibLinear) is large.
:pr:`13511` by :user:`Sylvain Marié <smarie>`.
- |Fix| Fix use of custom kernel not taking float entries such as string
kernels in :class:`svm.SVC` and :class:`svm.SVR`. Note that custom kennels
are now expected to validate their input where they previously received
valid numeric arrays.
:pr:`11296` by `Alexandre Gramfort`_ and :user:`Georgi Peev <georgipeev>`.
- |API| :class:`svm.SVR` and :class:`svm.OneClassSVM` attributes, `probA_` and
`probB_`, are now deprecated as they were not useful. :pr:`15558` by
`Thomas Fan`_.
:mod:`sklearn.tree`
...................
- |Fix| :func:`tree.plot_tree` `rotate` parameter was unused and has been
deprecated.
:pr:`15806` by :user:`Chiara Marmo <cmarmo>`.
- |Fix| Fix support of read-only float32 array input in ``predict``,
``decision_path`` and ``predict_proba`` methods of
:class:`tree.DecisionTreeClassifier`, :class:`tree.ExtraTreeClassifier` and
:class:`ensemble.GradientBoostingClassifier` as well as ``predict`` method of
:class:`tree.DecisionTreeRegressor`, :class:`tree.ExtraTreeRegressor`, and
:class:`ensemble.GradientBoostingRegressor`.
:pr:`16331` by :user:`Alexandre Batisse <batalex>`.
:mod:`sklearn.utils`
....................
- |MajorFeature| Estimators can now be displayed with a rich html
representation. This can be enabled in Jupyter notebooks by setting
`display='diagram'` in :func:`~sklearn.set_config`. The raw html can be
returned by using :func:`utils.estimator_html_repr`.
:pr:`14180` by `Thomas Fan`_.
- |Enhancement| improve error message in :func:`utils.validation.column_or_1d`.
:pr:`15926` by :user:`Loïc Estève <lesteve>`.
- |Enhancement| add warning in :func:`utils.check_array` for
pandas sparse DataFrame.
:pr:`16021` by :user:`Rushabh Vasani <rushabh-v>`.
- |Enhancement| :func:`utils.check_array` now constructs a sparse
matrix from a pandas DataFrame that contains only `SparseArray` columns.
:pr:`16728` by `Thomas Fan`_.
- |Enhancement| :func:`utils.check_array` supports pandas'
nullable integer dtype with missing values when `force_all_finite` is set to
`False` or `'allow-nan'` in which case the data is converted to floating
point values where `pd.NA` values are replaced by `np.nan`. As a consequence,
all :mod:`sklearn.preprocessing` transformers that accept numeric inputs with
missing values represented as `np.nan` now also accepts being directly fed
pandas dataframes with `pd.Int* or `pd.Uint*` typed columns that use `pd.NA`
as a missing value marker. :pr:`16508` by `Thomas Fan`_.
- |API| Passing classes to :func:`utils.estimator_checks.check_estimator` and
:func:`utils.estimator_checks.parametrize_with_checks` is now deprecated,
and support for classes will be removed in 0.24. Pass instances instead.
:pr:`17032` by `Nicolas Hug`_.
- |API| The private utility `_safe_tags` in `utils.estimator_checks` was
removed, hence all tags should be obtained through `estimator._get_tags()`.
Note that Mixins like `RegressorMixin` must come *before* base classes
in the MRO for `_get_tags()` to work properly.
:pr:`16950` by `Nicolas Hug`_.
- |FIX| `utils.all_estimators` now only returns public estimators.
:pr:`15380` by `Thomas Fan`_.
Miscellaneous
.............
- |MajorFeature| Adds a HTML representation of estimators to be shown in
a jupyter notebook or lab. This visualization is activated by setting the
`display` option in :func:`sklearn.set_config`. :pr:`14180` by
`Thomas Fan`_.
- |Enhancement| ``scikit-learn`` now works with ``mypy`` without errors.
:pr:`16726` by `Roman Yurchak`_.
- |API| Most estimators now expose a `n_features_in_` attribute. This
attribute is equal to the number of features passed to the `fit` method.
See `SLEP010
<https://scikit-learn-enhancement-proposals.readthedocs.io/en/latest/slep010/proposal.html>`_
for details. :pr:`16112` by `Nicolas Hug`_.
- |API| Estimators now have a `requires_y` tags which is False by default
except for estimators that inherit from `~sklearn.base.RegressorMixin` or
`~sklearn.base.ClassifierMixin`. This tag is used to ensure that a proper
error message is raised when y was expected but None was passed.
:pr:`16622` by `Nicolas Hug`_.
- |API| The default setting `print_changed_only` has been changed from False
to True. This means that the `repr` of estimators is now more concise and
only shows the parameters whose default value has been changed when
printing an estimator. You can restore the previous behaviour by using
`sklearn.set_config(print_changed_only=False)`. Also, note that it is
always possible to quickly inspect the parameters of any estimator using
`est.get_params(deep=False)`. :pr:`17061` by `Nicolas Hug`_.
.. rubric:: Code and documentation contributors
Thanks to everyone who has contributed to the maintenance and improvement of the
project since version 0.22, including:
Abbie Popa, Adrin Jalali, Aleksandra Kocot, Alexandre Batisse, Alexandre
Gramfort, Alex Henrie, Alex Itkes, Alex Liang, alexshacked, Alonso Silva
Allende, Ana Casado, Andreas Mueller, Angela Ambroz, Ankit810, Arie Pratama
Sutiono, Arunav Konwar, Baptiste Maingret, Benjamin Beier Liu, bernie gray,
Bharathi Srinivasan, Bharat Raghunathan, Bibhash Chandra Mitra, Brian Wignall,
brigi, Brigitta Sipőcz, Carlos H Brandt, CastaChick, castor, cgsavard, Chiara
Marmo, Chris Gregory, Christian Kastner, Christian Lorentzen, Corrie
Bartelheimer, Daniël van Gelder, Daphne, David Breuer, david-cortes, dbauer9,
Divyaprabha M, Edward Qian, Ekaterina Borovikova, ELNS, Emily Taylor, Erich
Schubert, Eric Leung, Evgeni Chasnovski, Fabiana, Facundo Ferrín, Fan,
Franziska Boenisch, Gael Varoquaux, Gaurav Sharma, Geoffrey Bolmier, Georgi
Peev, gholdman1, Gonthier Nicolas, Gregory Morse, Gregory R. Lee, Guillaume
Lemaitre, Gui Miotto, Hailey Nguyen, Hanmin Qin, Hao Chun Chang, HaoYin, Hélion
du Mas des Bourboux, Himanshu Garg, Hirofumi Suzuki, huangk10, Hugo van
Kemenade, Hye Sung Jung, indecisiveuser, inderjeet, J-A16, Jérémie du
Boisberranger, Jin-Hwan CHO, JJmistry, Joel Nothman, Johann Faouzi, Jon Haitz
Legarreta Gorroño, Juan Carlos Alfaro Jiménez, judithabk6, jumon, Kathryn
Poole, Katrina Ni, Kesshi Jordan, Kevin Loftis, Kevin Markham,
krishnachaitanya9, Lam Gia Thuan, Leland McInnes, Lisa Schwetlick, lkubin, Loic
Esteve, lopusz, lrjball, lucgiffon, lucyleeow, Lucy Liu, Lukas Kemkes, Maciej J
Mikulski, Madhura Jayaratne, Magda Zielinska, maikia, Mandy Gu, Manimaran,
Manish Aradwad, Maren Westermann, Maria, Mariana Meireles, Marie Douriez,
Marielle, Mateusz Górski, mathurinm, Matt Hall, Maura Pintor, mc4229, meyer89,
m.fab, Michael Shoemaker, Michał Słapek, Mina Naghshhnejad, mo, Mohamed
Maskani, Mojca Bertoncelj, narendramukherjee, ngshya, Nicholas Won, Nicolas
Hug, nicolasservel, Niklas, @nkish, Noa Tamir, Oleksandr Pavlyk, olicairns,
Oliver Urs Lenz, Olivier Grisel, parsons-kyle-89, Paula, Pete Green, Pierre
Delanoue, pspachtholz, Pulkit Mehta, Qizhi Jiang, Quang Nguyen, rachelcjordan,
raduspaimoc, Reshama Shaikh, Riccardo Folloni, Rick Mackenbach, Ritchie Ng,
Roman Feldbauer, Roman Yurchak, Rory Hartong-Redden, Rüdiger Busche, Rushabh
Vasani, Sambhav Kothari, Samesh Lakhotia, Samuel Duan, SanthoshBala18, Santiago
M. Mola, Sarat Addepalli, scibol, Sebastian Kießling, SergioDSR, Sergul Aydore,
Shiki-H, shivamgargsya, SHUBH CHATTERJEE, Siddharth Gupta, simonamaggio,
smarie, Snowhite, stareh, Stephen Blystone, Stephen Marsh, Sunmi Yoon,
SylvainLan, talgatomarov, tamirlan1, th0rwas, theoptips, Thomas J Fan, Thomas
Li, Thomas Schmitt, Tim Nonner, Tim Vink, Tiphaine Viard, Tirth Patel, Titus
Christian, Tom Dupré la Tour, trimeta, Vachan D A, Vandana Iyer, Venkatachalam
N, waelbenamara, wconnell, wderose, wenliwyan, Windber, wornbb, Yu-Hang "Maxin"
Tang