| Home | Trees | Indices | Help |
|
|---|
|
|
Linear Support Vector Classification.
This node has been automatically generated by wrapping the ``sklearn.svm.classes.LinearSVC`` class
from the ``sklearn`` library. The wrapped instance can be accessed
through the ``scikits_alg`` attribute.
Similar to SVC with parameter kernel='linear', but implemented in terms of
liblinear rather than libsvm, so it has more flexibility in the choice of
penalties and loss functions and should scale better to large numbers of
samples.
This class supports both dense and sparse input and the multiclass support
is handled according to a one-vs-the-rest scheme.
Read more in the :ref:`User Guide <svm_classification>`.
**Parameters**
C : float, optional (default=1.0)
Penalty parameter C of the error term.
loss : string, 'hinge' or 'squared_hinge' (default='squared_hinge')
Specifies the loss function. 'hinge' is the standard SVM loss
(used e.g. by the SVC class) while 'squared_hinge' is the
square of the hinge loss.
penalty : string, 'l1' or 'l2' (default='l2')
Specifies the norm used in the penalization. The 'l2'
penalty is the standard used in SVC. The 'l1' leads to ``coef_``
vectors that are sparse.
dual : bool, (default=True)
Select the algorithm to either solve the dual or primal
optimization problem. Prefer dual=False when n_samples > n_features.
tol : float, optional (default=1e-4)
Tolerance for stopping criteria.
multi_class: string, 'ovr' or 'crammer_singer' (default='ovr')
Determines the multi-class strategy if `y` contains more than
two classes.
``"ovr"`` trains n_classes one-vs-rest classifiers, while ``"crammer_singer"``
optimizes a joint objective over all classes.
While `crammer_singer` is interesting from a theoretical perspective
as it is consistent, it is seldom used in practice as it rarely leads
to better accuracy and is more expensive to compute.
If ``"crammer_singer"`` is chosen, the options loss, penalty and dual will
be ignored.
fit_intercept : boolean, optional (default=True)
Whether to calculate the intercept for this model. If set
to false, no intercept will be used in calculations
(i.e. data is expected to be already centered).
intercept_scaling : float, optional (default=1)
When self.fit_intercept is True, instance vector x becomes
``[x, self.intercept_scaling]``,
i.e. a "synthetic" feature with constant value equals to
intercept_scaling is appended to the instance vector.
The intercept becomes intercept_scaling * synthetic feature weight
Note! the synthetic feature weight is subject to l1/l2 regularization
as all other features.
To lessen the effect of regularization on synthetic feature weight
(and therefore on the intercept) intercept_scaling has to be increased.
class_weight : {dict, 'balanced'}, optional
Set the parameter C of class i to ``class_weight[i]*C`` for
SVC. If not given, all classes are supposed to have
weight one.
The "balanced" mode uses the values of y to automatically adjust
weights inversely proportional to class frequencies in the input data
as ``n_samples / (n_classes * np.bincount(y))``
verbose : int, (default=0)
Enable verbose output. Note that this setting takes advantage of a
per-process runtime setting in liblinear that, if enabled, may not work
properly in a multithreaded context.
random_state : int seed, RandomState instance, or None (default=None)
The seed of the pseudo random number generator to use when
shuffling the data.
max_iter : int, (default=1000)
The maximum number of iterations to be run.
**Attributes**
``coef_`` : array, shape = [n_features] if n_classes == 2 else [n_classes, n_features]
Weights assigned to the features (coefficients in the primal
problem). This is only available in the case of a linear kernel.
``coef_`` is a readonly property derived from ``raw_coef_`` that
follows the internal memory layout of liblinear.
``intercept_`` : array, shape = [1] if n_classes == 2 else [n_classes]
Constants in decision function.
**Notes**
The underlying C implementation uses a random number generator to
select features when fitting the model. It is thus not uncommon
to have slightly different results for the same input data. If
that happens, try with a smaller ``tol`` parameter.
The underlying implementation, liblinear, uses a sparse internal
representation for the data that will incur a memory copy.
Predict output may not match that of standalone liblinear in certain
cases. See :ref:`differences from liblinear <liblinear_differences>`
in the narrative documentation.
**References**
`LIBLINEAR: A Library for Large Linear Classification
<http://www.csie.ntu.edu.tw/~cjlin/liblinear/>`__
See also
SVC
Implementation of Support Vector Machine classifier using libsvm:
- the kernel can be non-linear but its SMO algorithm does not
- scale to large number of samples as LinearSVC does.
Furthermore SVC multi-class mode is implemented using one
vs one scheme while LinearSVC uses one vs the rest. It is
possible to implement one vs the rest with SVC by using the
:class:`sklearn.multiclass.OneVsRestClassifier` wrapper.
Finally SVC can fit dense data without memory copy if the input
is C-contiguous. Sparse data will still incur memory copy though.
sklearn.linear_model.SGDClassifier
SGDClassifier can optimize the same cost function as LinearSVC
by adjusting the penalty and loss parameters. In addition it requires
less memory, allows incremental (online) learning, and implements
various loss functions and regularization regimes.
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
|||
|
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 |
|||
|
|||
Linear Support Vector Classification.
This node has been automatically generated by wrapping the ``sklearn.svm.classes.LinearSVC`` class
from the ``sklearn`` library. The wrapped instance can be accessed
through the ``scikits_alg`` attribute.
Similar to SVC with parameter kernel='linear', but implemented in terms of
liblinear rather than libsvm, so it has more flexibility in the choice of
penalties and loss functions and should scale better to large numbers of
samples.
This class supports both dense and sparse input and the multiclass support
is handled according to a one-vs-the-rest scheme.
Read more in the :ref:`User Guide <svm_classification>`.
**Parameters**
C : float, optional (default=1.0)
Penalty parameter C of the error term.
loss : string, 'hinge' or 'squared_hinge' (default='squared_hinge')
Specifies the loss function. 'hinge' is the standard SVM loss
(used e.g. by the SVC class) while 'squared_hinge' is the
square of the hinge loss.
penalty : string, 'l1' or 'l2' (default='l2')
Specifies the norm used in the penalization. The 'l2'
penalty is the standard used in SVC. The 'l1' leads to ``coef_``
vectors that are sparse.
dual : bool, (default=True)
Select the algorithm to either solve the dual or primal
optimization problem. Prefer dual=False when n_samples > n_features.
tol : float, optional (default=1e-4)
Tolerance for stopping criteria.
multi_class: string, 'ovr' or 'crammer_singer' (default='ovr')
Determines the multi-class strategy if `y` contains more than
two classes.
``"ovr"`` trains n_classes one-vs-rest classifiers, while ``"crammer_singer"``
optimizes a joint objective over all classes.
While `crammer_singer` is interesting from a theoretical perspective
as it is consistent, it is seldom used in practice as it rarely leads
to better accuracy and is more expensive to compute.
If ``"crammer_singer"`` is chosen, the options loss, penalty and dual will
be ignored.
fit_intercept : boolean, optional (default=True)
Whether to calculate the intercept for this model. If set
to false, no intercept will be used in calculations
(i.e. data is expected to be already centered).
intercept_scaling : float, optional (default=1)
When self.fit_intercept is True, instance vector x becomes
``[x, self.intercept_scaling]``,
i.e. a "synthetic" feature with constant value equals to
intercept_scaling is appended to the instance vector.
The intercept becomes intercept_scaling * synthetic feature weight
Note! the synthetic feature weight is subject to l1/l2 regularization
as all other features.
To lessen the effect of regularization on synthetic feature weight
(and therefore on the intercept) intercept_scaling has to be increased.
class_weight : {dict, 'balanced'}, optional
Set the parameter C of class i to ``class_weight[i]*C`` for
SVC. If not given, all classes are supposed to have
weight one.
The "balanced" mode uses the values of y to automatically adjust
weights inversely proportional to class frequencies in the input data
as ``n_samples / (n_classes * np.bincount(y))``
verbose : int, (default=0)
Enable verbose output. Note that this setting takes advantage of a
per-process runtime setting in liblinear that, if enabled, may not work
properly in a multithreaded context.
random_state : int seed, RandomState instance, or None (default=None)
The seed of the pseudo random number generator to use when
shuffling the data.
max_iter : int, (default=1000)
The maximum number of iterations to be run.
**Attributes**
``coef_`` : array, shape = [n_features] if n_classes == 2 else [n_classes, n_features]
Weights assigned to the features (coefficients in the primal
problem). This is only available in the case of a linear kernel.
``coef_`` is a readonly property derived from ``raw_coef_`` that
follows the internal memory layout of liblinear.
``intercept_`` : array, shape = [1] if n_classes == 2 else [n_classes]
Constants in decision function.
**Notes**
The underlying C implementation uses a random number generator to
select features when fitting the model. It is thus not uncommon
to have slightly different results for the same input data. If
that happens, try with a smaller ``tol`` parameter.
The underlying implementation, liblinear, uses a sparse internal
representation for the data that will incur a memory copy.
Predict output may not match that of standalone liblinear in certain
cases. See :ref:`differences from liblinear <liblinear_differences>`
in the narrative documentation.
**References**
`LIBLINEAR: A Library for Large Linear Classification
<http://www.csie.ntu.edu.tw/~cjlin/liblinear/>`__
See also
SVC
Implementation of Support Vector Machine classifier using libsvm:
- the kernel can be non-linear but its SMO algorithm does not
- scale to large number of samples as LinearSVC does.
Furthermore SVC multi-class mode is implemented using one
vs one scheme while LinearSVC uses one vs the rest. It is
possible to implement one vs the rest with SVC by using the
:class:`sklearn.multiclass.OneVsRestClassifier` wrapper.
Finally SVC can fit dense data without memory copy if the input
is C-contiguous. Sparse data will still incur memory copy though.
sklearn.linear_model.SGDClassifier
SGDClassifier can optimize the same cost function as LinearSVC
by adjusting the penalty and loss parameters. In addition it requires
less memory, allows incremental (online) learning, and implements
various loss functions and regularization regimes.
|
|
|
Transform the data and labels lists to array objects and reshape them.
|
|
|
Predict class labels for samples in X. This node has been automatically generated by wrapping the sklearn.svm.classes.LinearSVC class from the sklearn library. The wrapped instance can be accessed through the scikits_alg attribute. Parameters
Returns
|
Fit the model according to the given training data. This node has been automatically generated by wrapping the sklearn.svm.classes.LinearSVC 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 |