val of_pyobject : Py.Object.t -> tval to_pyobject : t -> Py.Object.tval create :
?nu:float ->
?kernel:string ->
?degree:int ->
?gamma:[ `Scale | `Auto | `Float of float ] ->
?coef0:float ->
?shrinking:bool ->
?probability:bool ->
?tol:float ->
?cache_size:float ->
?class_weight:[ `DictIntToFloat of (int * float) list | `Balanced ] ->
?verbose:bool ->
?max_iter:int ->
?decision_function_shape:[ `Ovo | `Ovr ] ->
?break_ties:bool ->
?random_state:[ `Int of int | `RandomState of Py.Object.t | `None ] ->
unit ->
tNu-Support Vector Classification.
Similar to SVC but uses a parameter to control the number of support vectors.
The implementation is based on libsvm.
Read more in the :ref:`User Guide <svm_classification>`.
Parameters ---------- nu : float, optional (default=0.5) An upper bound on the fraction of training errors and a lower bound of the fraction of support vectors. Should be in the interval (0, 1].
kernel : string, optional (default='rbf') Specifies the kernel type to be used in the algorithm. It must be one of 'linear', 'poly', 'rbf', 'sigmoid', 'precomputed' or a callable. If none is given, 'rbf' will be used. If a callable is given it is used to precompute the kernel matrix.
degree : int, optional (default=3) Degree of the polynomial kernel function ('poly'). Ignored by all other kernels.
gamma : 'scale', 'auto' or float, optional (default='scale') Kernel coefficient for 'rbf', 'poly' and 'sigmoid'.
.. versionchanged:: 0.22 The default value of ``gamma`` changed from 'auto' to 'scale'.
coef0 : float, optional (default=0.0) Independent term in kernel function. It is only significant in 'poly' and 'sigmoid'.
shrinking : boolean, optional (default=True) Whether to use the shrinking heuristic.
probability : boolean, optional (default=False) Whether to enable probability estimates. This must be enabled prior to calling `fit`, will slow down that method as it internally uses 5-fold cross-validation, and `predict_proba` may be inconsistent with `predict`. Read more in the :ref:`User Guide <scores_probabilities>`.
tol : float, optional (default=1e-3) Tolerance for stopping criterion.
cache_size : float, optional Specify the size of the kernel cache (in MB).
class_weight : dict, 'balanced', optional Set the parameter C of class i to class_weighti*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 as ``n_samples / (n_classes * np.bincount(y))``
verbose : bool, default: False Enable verbose output. Note that this setting takes advantage of a per-process runtime setting in libsvm that, if enabled, may not work properly in a multithreaded context.
max_iter : int, optional (default=-1) Hard limit on iterations within solver, or -1 for no limit.
decision_function_shape : 'ovo', 'ovr', default='ovr' Whether to return a one-vs-rest ('ovr') decision function of shape (n_samples, n_classes) as all other classifiers, or the original one-vs-one ('ovo') decision function of libsvm which has shape (n_samples, n_classes * (n_classes - 1) / 2).
.. versionchanged:: 0.19 decision_function_shape is 'ovr' by default.
.. versionadded:: 0.17 *decision_function_shape='ovr'* is recommended.
.. versionchanged:: 0.17 Deprecated *decision_function_shape='ovo' and None*.
break_ties : bool, optional (default=False) If true, ``decision_function_shape='ovr'``, and number of classes > 2, :term:`predict` will break ties according to the confidence values of :term:`decision_function`; otherwise the first class among the tied classes is returned. Please note that breaking ties comes at a relatively high computational cost compared to a simple predict.
.. versionadded:: 0.22
random_state : int, RandomState instance or None, optional (default=None) The seed of the pseudo random number generator used when shuffling the data for probability estimates. If int, random_state is the seed used by the random number generator; If RandomState instance, random_state is the random number generator; If None, the random number generator is the RandomState instance used by `np.random`.
Attributes ---------- support_ : array-like of shape (n_SV) Indices of support vectors.
support_vectors_ : array-like of shape (n_SV, n_features) Support vectors.
n_support_ : array-like, dtype=int32, shape = n_class Number of support vectors for each class.
dual_coef_ : array, shape = n_class-1, n_SV Coefficients of the support vector in the decision function. For multiclass, coefficient for all 1-vs-1 classifiers. The layout of the coefficients in the multiclass case is somewhat non-trivial. See the section about multi-class classification in the SVM section of the User Guide for details.
coef_ : array, shape = n_class * (n_class-1) / 2, 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 readonly property derived from `dual_coef_` and `support_vectors_`.
intercept_ : ndarray of shape (n_class * (n_class-1) / 2,) Constants in decision function.
classes_ : array of shape (n_classes,) The unique classes labels.
fit_status_ : int 0 if correctly fitted, 1 if the algorithm did not converge.
probA_ : ndarray, shape of (n_class * (n_class-1) / 2,) probB_ : ndarray of shape (n_class * (n_class-1) / 2,) If `probability=True`, it corresponds to the parameters learned in Platt scaling to produce probability estimates from decision values. If `probability=False`, it's an empty array. Platt scaling uses the logistic function ``1 / (1 + exp(decision_value * probA_ + probB_))`` where ``probA_`` and ``probB_`` are learned from the dataset 2_. For more information on the multiclass case and training procedure see section 8 of 1_.
class_weight_ : ndarray of shape (n_class,) Multipliers of parameter C of each class. Computed based on the ``class_weight`` parameter.
shape_fit_ : tuple of int of shape (n_dimensions_of_X,) Array dimensions of training vector ``X``.
Examples -------- >>> import numpy as np >>> X = np.array([-1, -1], [-2, -1], [1, 1], [2, 1]) >>> y = np.array(1, 1, 2, 2) >>> from sklearn.svm import NuSVC >>> clf = NuSVC() >>> clf.fit(X, y) NuSVC() >>> print(clf.predict([-0.8, -1])) 1
See also -------- SVC Support Vector Machine for classification using libsvm.
LinearSVC Scalable linear Support Vector Machine for classification using liblinear.
References ---------- .. 1 `LIBSVM: A Library for Support Vector Machines <http://www.csie.ntu.edu.tw/~cjlin/papers/libsvm.pdf>`_
.. 2 `Platt, John (1999). "Probabilistic outputs for support vector machines and comparison to regularizedlikelihood methods." <http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.41.1639>`_
Evaluates the decision function for the samples in X.
Parameters ---------- X : array-like, shape (n_samples, n_features)
Returns ------- X : array-like, shape (n_samples, n_classes * (n_classes-1) / 2) Returns the decision function of the sample for each class in the model. If decision_function_shape='ovr', the shape is (n_samples, n_classes).
Notes ----- If decision_function_shape='ovo', the function values are proportional to the distance of the samples X to the separating hyperplane. If the exact distances are required, divide the function values by the norm of the weight vector (``coef_``). See also `this question <https://stats.stackexchange.com/questions/14876/ interpreting-distance-from-hyperplane-in-svm>`_ for further details. If decision_function_shape='ovr', the decision function is a monotonic transformation of ovo decision function.
val fit :
?sample_weight:Ndarray.t ->
x:[ `Ndarray of Ndarray.t | `SparseMatrix of Csr_matrix.t ] ->
y:Ndarray.t ->
t ->
tFit the SVM model according to the given training data.
Parameters ---------- X : array-like, sparse matrix, shape (n_samples, n_features) Training vectors, where n_samples is the number of samples and n_features is the number of features. For kernel="precomputed", the expected shape of X is (n_samples, n_samples).
y : array-like, shape (n_samples,) Target values (class labels in classification, real numbers in regression)
sample_weight : array-like, shape (n_samples,) Per-sample weights. Rescale C per sample. Higher weights force the classifier to put more emphasis on these points.
Returns ------- self : object
Notes ----- If X and y are not C-ordered and contiguous arrays of np.float64 and X is not a scipy.sparse.csr_matrix, X and/or y may be copied.
If X is a dense array, then the other methods will not support sparse matrices as input.
val get_params : ?deep:bool -> t -> Py.Object.tGet parameters for this estimator.
Parameters ---------- deep : bool, default=True If True, will return the parameters for this estimator and contained subobjects that are estimators.
Returns ------- params : mapping of string to any Parameter names mapped to their values.
val predict :
x:[ `Ndarray of Ndarray.t | `SparseMatrix of Csr_matrix.t ] ->
t ->
Ndarray.tPerform classification on samples in X.
For an one-class model, +1 or -1 is returned.
Parameters ---------- X : array-like, sparse matrix, shape (n_samples, n_features) For kernel="precomputed", the expected shape of X is n_samples_test, n_samples_train
Returns ------- y_pred : array, shape (n_samples,) Class labels for samples in X.
Return the mean accuracy on the given test data and labels.
In multi-label classification, this is the subset accuracy which is a harsh metric since you require for each sample that each label set be correctly predicted.
Parameters ---------- X : array-like of shape (n_samples, n_features) Test samples.
y : array-like of shape (n_samples,) or (n_samples, n_outputs) True labels for X.
sample_weight : array-like of shape (n_samples,), default=None Sample weights.
Returns ------- score : float Mean accuracy of self.predict(X) wrt. y.
val set_params : ?params:(string * Py.Object.t) list -> t -> tSet the parameters of this estimator.
The method works on simple estimators as well as on nested objects (such as pipelines). The latter have parameters of the form ``<component>__<parameter>`` so that it's possible to update each component of a nested object.
Parameters ---------- **params : dict Estimator parameters.
Returns ------- self : object Estimator instance.
val n_support_ : t -> Py.Object.tAttribute n_support_: see constructor for documentation
val fit_status_ : t -> intAttribute fit_status_: see constructor for documentation
val probA_ : t -> Py.Object.tAttribute probA_: see constructor for documentation
val shape_fit_ : t -> Py.Object.tAttribute shape_fit_: see constructor for documentation
val to_string : t -> stringPrint the object to a human-readable representation.
val show : t -> stringPrint the object to a human-readable representation.
val pp : Format.formatter -> t -> unitPretty-print the object to a formatter.