| Home | Trees | Indices | Help |
|
|---|
|
|
Probability calibration with isotonic regression or sigmoid.
This node has been automatically generated by wrapping the ``sklearn.calibration.CalibratedClassifierCV`` class
from the ``sklearn`` library. The wrapped instance can be accessed
through the ``scikits_alg`` attribute.
With this class, the base_estimator is fit on the train set of the
cross-validation generator and the test set is used for calibration.
The probabilities for each of the folds are then averaged
for prediction. In case that cv="prefit" is passed to ``__init__``,
it is it is assumed that base_estimator has been
fitted already and all data is used for calibration. Note that
data for fitting the classifier and for calibrating it must be disjoint.
Read more in the :ref:`User Guide <calibration>`.
**Parameters**
base_estimator : instance BaseEstimator
The classifier whose output decision function needs to be calibrated
to offer more accurate predict_proba outputs. If cv=prefit, the
classifier must have been fit already on data.
method : 'sigmoid' or 'isotonic'
The method to use for calibration. Can be 'sigmoid' which
corresponds to Platt's method or 'isotonic' which is a
non-parameteric approach. It is not advised to use isotonic calibration
with too few calibration samples ``(<<1000)`` since it tends to overfit.
Use sigmoids (Platt's calibration) in this case.
cv : integer, cross-validation generator, iterable or "prefit", optional
Determines the cross-validation splitting strategy.
Possible inputs for cv are:
- None, to use the default 3-fold cross-validation,
- integer, to specify the number of folds.
- An object to be used as a cross-validation generator.
- An iterable yielding train/test splits.
For integer/None inputs, if ``y`` is binary or multiclass,
:class:`StratifiedKFold` used. If ``y`` is neither binary nor
multiclass, :class:`KFold` is used.
Refer :ref:`User Guide <cross_validation>` for the various
cross-validation strategies that can be used here.
If "prefit" is passed, it is assumed that base_estimator has been
fitted already and all data is used for calibration.
**Attributes**
``classes_`` : array, shape (n_classes)
The class labels.
calibrated_classifiers_: list (len() equal to cv or 1 if cv == "prefit")
The list of calibrated classifiers, one for each crossvalidation fold,
which has been fitted on all but the validation fold and calibrated
on the validation fold.
**References**
.. [1] Obtaining calibrated probability estimates from decision trees
and naive Bayesian classifiers, B. Zadrozny & C. Elkan, ICML 2001
.. [2] Transforming Classifier Scores into Accurate Multiclass
Probability Estimates, B. Zadrozny & C. Elkan, (KDD 2002)
.. [3] Probabilistic Outputs for Support Vector Machines and Comparisons to
Regularized Likelihood Methods, J. Platt, (1999)
.. [4] Predicting Good Probabilities with Supervised Learning,
A. Niculescu-Mizil & R. Caruana, ICML 2005
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
Inherited from Inherited from Inherited from |
|||
| Inherited from ClassifierCumulator | |||
|---|---|---|---|
|
|||
|
|||
|
|||
| Inherited from ClassifierNode | |||
|
|||
|
|||
|
|||
|
|||
|
|||
| Inherited from Node | |||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
Inherited from |
|||
| Inherited from Node | |||
|---|---|---|---|
|
_train_seq List of tuples: |
|||
|
dtype dtype |
|||
|
input_dim Input dimensions |
|||
|
output_dim Output dimensions |
|||
|
supported_dtypes Supported dtypes |
|||
|
|||
Probability calibration with isotonic regression or sigmoid.
This node has been automatically generated by wrapping the ``sklearn.calibration.CalibratedClassifierCV`` class
from the ``sklearn`` library. The wrapped instance can be accessed
through the ``scikits_alg`` attribute.
With this class, the base_estimator is fit on the train set of the
cross-validation generator and the test set is used for calibration.
The probabilities for each of the folds are then averaged
for prediction. In case that cv="prefit" is passed to ``__init__``,
it is it is assumed that base_estimator has been
fitted already and all data is used for calibration. Note that
data for fitting the classifier and for calibrating it must be disjoint.
Read more in the :ref:`User Guide <calibration>`.
**Parameters**
base_estimator : instance BaseEstimator
The classifier whose output decision function needs to be calibrated
to offer more accurate predict_proba outputs. If cv=prefit, the
classifier must have been fit already on data.
method : 'sigmoid' or 'isotonic'
The method to use for calibration. Can be 'sigmoid' which
corresponds to Platt's method or 'isotonic' which is a
non-parameteric approach. It is not advised to use isotonic calibration
with too few calibration samples ``(<<1000)`` since it tends to overfit.
Use sigmoids (Platt's calibration) in this case.
cv : integer, cross-validation generator, iterable or "prefit", optional
Determines the cross-validation splitting strategy.
Possible inputs for cv are:
- None, to use the default 3-fold cross-validation,
- integer, to specify the number of folds.
- An object to be used as a cross-validation generator.
- An iterable yielding train/test splits.
For integer/None inputs, if ``y`` is binary or multiclass,
:class:`StratifiedKFold` used. If ``y`` is neither binary nor
multiclass, :class:`KFold` is used.
Refer :ref:`User Guide <cross_validation>` for the various
cross-validation strategies that can be used here.
If "prefit" is passed, it is assumed that base_estimator has been
fitted already and all data is used for calibration.
**Attributes**
``classes_`` : array, shape (n_classes)
The class labels.
calibrated_classifiers_: list (len() equal to cv or 1 if cv == "prefit")
The list of calibrated classifiers, one for each crossvalidation fold,
which has been fitted on all but the validation fold and calibrated
on the validation fold.
**References**
.. [1] Obtaining calibrated probability estimates from decision trees
and naive Bayesian classifiers, B. Zadrozny & C. Elkan, ICML 2001
.. [2] Transforming Classifier Scores into Accurate Multiclass
Probability Estimates, B. Zadrozny & C. Elkan, (KDD 2002)
.. [3] Probabilistic Outputs for Support Vector Machines and Comparisons to
Regularized Likelihood Methods, J. Platt, (1999)
.. [4] Predicting Good Probabilities with Supervised Learning,
A. Niculescu-Mizil & R. Caruana, ICML 2005
|
|
|
Transform the data and labels lists to array objects and reshape them.
|
|
|
Predict the target of new samples. Can be different from the prediction of the uncalibrated classifier. This node has been automatically generated by wrapping the sklearn.calibration.CalibratedClassifierCV class from the sklearn library. The wrapped instance can be accessed through the scikits_alg attribute. Parameters
Returns
|
Fit the calibrated model This node has been automatically generated by wrapping the sklearn.calibration.CalibratedClassifierCV class from the sklearn library. The wrapped instance can be accessed through the scikits_alg attribute. Parameters
Returns
|
| Home | Trees | Indices | Help |
|
|---|
| Generated by Epydoc 3.0.1 on Tue Mar 8 12:39:48 2016 | http://epydoc.sourceforge.net |