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.. include:: _contributors.rst
.. currentmodule:: sklearn
============
Version 0.14
============
.. _changes_0_14:
Version 0.14
===============
**August 7, 2013**
Changelog
---------
- Missing values with sparse and dense matrices can be imputed with the
transformer `preprocessing.Imputer` by `Nicolas Trésegnie`_.
- The core implementation of decisions trees has been rewritten from
scratch, allowing for faster tree induction and lower memory
consumption in all tree-based estimators. By `Gilles Louppe`_.
- Added :class:`ensemble.AdaBoostClassifier` and
:class:`ensemble.AdaBoostRegressor`, by `Noel Dawe`_ and
`Gilles Louppe`_. See the :ref:`AdaBoost <adaboost>` section of the user
guide for details and examples.
- Added `grid_search.RandomizedSearchCV` and
`grid_search.ParameterSampler` for randomized hyperparameter
optimization. By `Andreas Müller`_.
- Added :ref:`biclustering <biclustering>` algorithms
(`sklearn.cluster.bicluster.SpectralCoclustering` and
`sklearn.cluster.bicluster.SpectralBiclustering`), data
generation methods (:func:`sklearn.datasets.make_biclusters` and
:func:`sklearn.datasets.make_checkerboard`), and scoring metrics
(:func:`sklearn.metrics.consensus_score`). By `Kemal Eren`_.
- Added :ref:`Restricted Boltzmann Machines<rbm>`
(:class:`neural_network.BernoulliRBM`). By `Yann Dauphin`_.
- Python 3 support by :user:`Justin Vincent <justinvf>`, `Lars Buitinck`_,
:user:`Subhodeep Moitra <smoitra87>` and `Olivier Grisel`_. All tests now pass under
Python 3.3.
- Ability to pass one penalty (alpha value) per target in
:class:`linear_model.Ridge`, by @eickenberg and `Mathieu Blondel`_.
- Fixed `sklearn.linear_model.stochastic_gradient.py` L2 regularization
issue (minor practical significance).
By :user:`Norbert Crombach <norbert>` and `Mathieu Blondel`_ .
- Added an interactive version of `Andreas Müller`_'s
`Machine Learning Cheat Sheet (for scikit-learn)
<https://peekaboo-vision.blogspot.de/2013/01/machine-learning-cheat-sheet-for-scikit.html>`_
to the documentation. See :ref:`Choosing the right estimator <ml_map>`.
By `Jaques Grobler`_.
- `grid_search.GridSearchCV` and
`cross_validation.cross_val_score` now support the use of advanced
scoring function such as area under the ROC curve and f-beta scores.
See :ref:`scoring_parameter` for details. By `Andreas Müller`_
and `Lars Buitinck`_.
Passing a function from :mod:`sklearn.metrics` as ``score_func`` is
deprecated.
- Multi-label classification output is now supported by
:func:`metrics.accuracy_score`, :func:`metrics.zero_one_loss`,
:func:`metrics.f1_score`, :func:`metrics.fbeta_score`,
:func:`metrics.classification_report`,
:func:`metrics.precision_score` and :func:`metrics.recall_score`
by `Arnaud Joly`_.
- Two new metrics :func:`metrics.hamming_loss` and
`metrics.jaccard_similarity_score`
are added with multi-label support by `Arnaud Joly`_.
- Speed and memory usage improvements in
:class:`feature_extraction.text.CountVectorizer` and
:class:`feature_extraction.text.TfidfVectorizer`,
by Jochen Wersdörfer and Roman Sinayev.
- The ``min_df`` parameter in
:class:`feature_extraction.text.CountVectorizer` and
:class:`feature_extraction.text.TfidfVectorizer`, which used to be 2,
has been reset to 1 to avoid unpleasant surprises (empty vocabularies)
for novice users who try it out on tiny document collections.
A value of at least 2 is still recommended for practical use.
- :class:`svm.LinearSVC`, :class:`linear_model.SGDClassifier` and
:class:`linear_model.SGDRegressor` now have a ``sparsify`` method that
converts their ``coef_`` into a sparse matrix, meaning stored models
trained using these estimators can be made much more compact.
- :class:`linear_model.SGDClassifier` now produces multiclass probability
estimates when trained under log loss or modified Huber loss.
- Hyperlinks to documentation in example code on the website by
:user:`Martin Luessi <mluessi>`.
- Fixed bug in :class:`preprocessing.MinMaxScaler` causing incorrect scaling
of the features for non-default ``feature_range`` settings. By `Andreas
Müller`_.
- ``max_features`` in :class:`tree.DecisionTreeClassifier`,
:class:`tree.DecisionTreeRegressor` and all derived ensemble estimators
now supports percentage values. By `Gilles Louppe`_.
- Performance improvements in :class:`isotonic.IsotonicRegression` by
`Nelle Varoquaux`_.
- :func:`metrics.accuracy_score` has an option normalize to return
the fraction or the number of correctly classified sample
by `Arnaud Joly`_.
- Added :func:`metrics.log_loss` that computes log loss, aka cross-entropy
loss. By Jochen Wersdörfer and `Lars Buitinck`_.
- A bug that caused :class:`ensemble.AdaBoostClassifier`'s to output
incorrect probabilities has been fixed.
- Feature selectors now share a mixin providing consistent ``transform``,
``inverse_transform`` and ``get_support`` methods. By `Joel Nothman`_.
- A fitted `grid_search.GridSearchCV` or
`grid_search.RandomizedSearchCV` can now generally be pickled.
By `Joel Nothman`_.
- Refactored and vectorized implementation of :func:`metrics.roc_curve`
and :func:`metrics.precision_recall_curve`. By `Joel Nothman`_.
- The new estimator :class:`sklearn.decomposition.TruncatedSVD`
performs dimensionality reduction using SVD on sparse matrices,
and can be used for latent semantic analysis (LSA).
By `Lars Buitinck`_.
- Added self-contained example of out-of-core learning on text data
:ref:`sphx_glr_auto_examples_applications_plot_out_of_core_classification.py`.
By :user:`Eustache Diemert <oddskool>`.
- The default number of components for
`sklearn.decomposition.RandomizedPCA` is now correctly documented
to be ``n_features``. This was the default behavior, so programs using it
will continue to work as they did.
- :class:`sklearn.cluster.KMeans` now fits several orders of magnitude
faster on sparse data (the speedup depends on the sparsity). By
`Lars Buitinck`_.
- Reduce memory footprint of FastICA by `Denis Engemann`_ and
`Alexandre Gramfort`_.
- Verbose output in `sklearn.ensemble.gradient_boosting` now uses
a column format and prints progress in decreasing frequency.
It also shows the remaining time. By `Peter Prettenhofer`_.
- `sklearn.ensemble.gradient_boosting` provides out-of-bag improvement
`oob_improvement_`
rather than the OOB score for model selection. An example that shows
how to use OOB estimates to select the number of trees was added.
By `Peter Prettenhofer`_.
- Most metrics now support string labels for multiclass classification
by `Arnaud Joly`_ and `Lars Buitinck`_.
- New OrthogonalMatchingPursuitCV class by `Alexandre Gramfort`_
and `Vlad Niculae`_.
- Fixed a bug in `sklearn.covariance.GraphLassoCV`: the
'alphas' parameter now works as expected when given a list of
values. By Philippe Gervais.
- Fixed an important bug in `sklearn.covariance.GraphLassoCV`
that prevented all folds provided by a CV object to be used (only
the first 3 were used). When providing a CV object, execution
time may thus increase significantly compared to the previous
version (bug results are correct now). By Philippe Gervais.
- `cross_validation.cross_val_score` and the `grid_search`
module is now tested with multi-output data by `Arnaud Joly`_.
- :func:`datasets.make_multilabel_classification` can now return
the output in label indicator multilabel format by `Arnaud Joly`_.
- K-nearest neighbors, :class:`neighbors.KNeighborsRegressor`
and :class:`neighbors.RadiusNeighborsRegressor`,
and radius neighbors, :class:`neighbors.RadiusNeighborsRegressor` and
:class:`neighbors.RadiusNeighborsClassifier` support multioutput data
by `Arnaud Joly`_.
- Random state in LibSVM-based estimators (:class:`svm.SVC`, :class:`svm.NuSVC`,
:class:`svm.OneClassSVM`, :class:`svm.SVR`, :class:`svm.NuSVR`) can now be
controlled. This is useful to ensure consistency in the probability
estimates for the classifiers trained with ``probability=True``. By
`Vlad Niculae`_.
- Out-of-core learning support for discrete naive Bayes classifiers
:class:`sklearn.naive_bayes.MultinomialNB` and
:class:`sklearn.naive_bayes.BernoulliNB` by adding the ``partial_fit``
method by `Olivier Grisel`_.
- New website design and navigation by `Gilles Louppe`_, `Nelle Varoquaux`_,
Vincent Michel and `Andreas Müller`_.
- Improved documentation on :ref:`multi-class, multi-label and multi-output
classification <multiclass>` by `Yannick Schwartz`_ and `Arnaud Joly`_.
- Better input and error handling in the :mod:`sklearn.metrics` module by
`Arnaud Joly`_ and `Joel Nothman`_.
- Speed optimization of the `hmm` module by :user:`Mikhail Korobov <kmike>`
- Significant speed improvements for :class:`sklearn.cluster.DBSCAN`
by `cleverless <https://github.com/cleverless>`_
API changes summary
-------------------
- The `auc_score` was renamed :func:`metrics.roc_auc_score`.
- Testing scikit-learn with ``sklearn.test()`` is deprecated. Use
``nosetests sklearn`` from the command line.
- Feature importances in :class:`tree.DecisionTreeClassifier`,
:class:`tree.DecisionTreeRegressor` and all derived ensemble estimators
are now computed on the fly when accessing the ``feature_importances_``
attribute. Setting ``compute_importances=True`` is no longer required.
By `Gilles Louppe`_.
- :class:`linear_model.lasso_path` and
:class:`linear_model.enet_path` can return its results in the same
format as that of :class:`linear_model.lars_path`. This is done by
setting the ``return_models`` parameter to ``False``. By
`Jaques Grobler`_ and `Alexandre Gramfort`_
- `grid_search.IterGrid` was renamed to `grid_search.ParameterGrid`.
- Fixed bug in `KFold` causing imperfect class balance in some
cases. By `Alexandre Gramfort`_ and Tadej Janež.
- :class:`sklearn.neighbors.BallTree` has been refactored, and a
:class:`sklearn.neighbors.KDTree` has been
added which shares the same interface. The Ball Tree now works with
a wide variety of distance metrics. Both classes have many new
methods, including single-tree and dual-tree queries, breadth-first
and depth-first searching, and more advanced queries such as
kernel density estimation and 2-point correlation functions.
By `Jake Vanderplas`_
- Support for scipy.spatial.cKDTree within neighbors queries has been
removed, and the functionality replaced with the new
:class:`sklearn.neighbors.KDTree` class.
- :class:`sklearn.neighbors.KernelDensity` has been added, which performs
efficient kernel density estimation with a variety of kernels.
- :class:`sklearn.decomposition.KernelPCA` now always returns output with
``n_components`` components, unless the new parameter ``remove_zero_eig``
is set to ``True``. This new behavior is consistent with the way
kernel PCA was always documented; previously, the removal of components
with zero eigenvalues was tacitly performed on all data.
- ``gcv_mode="auto"`` no longer tries to perform SVD on a densified
sparse matrix in :class:`sklearn.linear_model.RidgeCV`.
- Sparse matrix support in `sklearn.decomposition.RandomizedPCA`
is now deprecated in favor of the new ``TruncatedSVD``.
- `cross_validation.KFold` and
`cross_validation.StratifiedKFold` now enforce `n_folds >= 2`
otherwise a ``ValueError`` is raised. By `Olivier Grisel`_.
- :func:`datasets.load_files`'s ``charset`` and ``charset_errors``
parameters were renamed ``encoding`` and ``decode_errors``.
- Attribute ``oob_score_`` in :class:`sklearn.ensemble.GradientBoostingRegressor`
and :class:`sklearn.ensemble.GradientBoostingClassifier`
is deprecated and has been replaced by ``oob_improvement_`` .
- Attributes in OrthogonalMatchingPursuit have been deprecated
(copy_X, Gram, ...) and precompute_gram renamed precompute
for consistency. See #2224.
- :class:`sklearn.preprocessing.StandardScaler` now converts integer input
to float, and raises a warning. Previously it rounded for dense integer
input.
- :class:`sklearn.multiclass.OneVsRestClassifier` now has a
``decision_function`` method. This will return the distance of each
sample from the decision boundary for each class, as long as the
underlying estimators implement the ``decision_function`` method.
By `Kyle Kastner`_.
- Better input validation, warning on unexpected shapes for y.
People
------
List of contributors for release 0.14 by number of commits.
* 277 Gilles Louppe
* 245 Lars Buitinck
* 187 Andreas Mueller
* 124 Arnaud Joly
* 112 Jaques Grobler
* 109 Gael Varoquaux
* 107 Olivier Grisel
* 102 Noel Dawe
* 99 Kemal Eren
* 79 Joel Nothman
* 75 Jake VanderPlas
* 73 Nelle Varoquaux
* 71 Vlad Niculae
* 65 Peter Prettenhofer
* 64 Alexandre Gramfort
* 54 Mathieu Blondel
* 38 Nicolas Trésegnie
* 35 eustache
* 27 Denis Engemann
* 25 Yann N. Dauphin
* 19 Justin Vincent
* 17 Robert Layton
* 15 Doug Coleman
* 14 Michael Eickenberg
* 13 Robert Marchman
* 11 Fabian Pedregosa
* 11 Philippe Gervais
* 10 Jim Holmström
* 10 Tadej Janež
* 10 syhw
* 9 Mikhail Korobov
* 9 Steven De Gryze
* 8 sergeyf
* 7 Ben Root
* 7 Hrishikesh Huilgolkar
* 6 Kyle Kastner
* 6 Martin Luessi
* 6 Rob Speer
* 5 Federico Vaggi
* 5 Raul Garreta
* 5 Rob Zinkov
* 4 Ken Geis
* 3 A. Flaxman
* 3 Denton Cockburn
* 3 Dougal Sutherland
* 3 Ian Ozsvald
* 3 Johannes Schönberger
* 3 Robert McGibbon
* 3 Roman Sinayev
* 3 Szabo Roland
* 2 Diego Molla
* 2 Imran Haque
* 2 Jochen Wersdörfer
* 2 Sergey Karayev
* 2 Yannick Schwartz
* 2 jamestwebber
* 1 Abhijeet Kolhe
* 1 Alexander Fabisch
* 1 Bastiaan van den Berg
* 1 Benjamin Peterson
* 1 Daniel Velkov
* 1 Fazlul Shahriar
* 1 Felix Brockherde
* 1 Félix-Antoine Fortin
* 1 Harikrishnan S
* 1 Jack Hale
* 1 JakeMick
* 1 James McDermott
* 1 John Benediktsson
* 1 John Zwinck
* 1 Joshua Vredevoogd
* 1 Justin Pati
* 1 Kevin Hughes
* 1 Kyle Kelley
* 1 Matthias Ekman
* 1 Miroslav Shubernetskiy
* 1 Naoki Orii
* 1 Norbert Crombach
* 1 Rafael Cunha de Almeida
* 1 Rolando Espinoza La fuente
* 1 Seamus Abshere
* 1 Sergey Feldman
* 1 Sergio Medina
* 1 Stefano Lattarini
* 1 Steve Koch
* 1 Sturla Molden
* 1 Thomas Jarosch
* 1 Yaroslav Halchenko
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