{Kg#dZddlmZddlZddlmZmZmZm Z ddl m Z ddl m Z mZddlmZmZdd lmZmZGd d eeeZy) zKernel ridge regression.)RealN) BaseEstimatorMultiOutputMixinRegressorMixin _fit_context)_solve_cholesky_kernel)PAIRWISE_KERNEL_FUNCTIONSpairwise_kernels)Interval StrOptions)_check_sample_weightcheck_is_fittedc eZdZUdZeeddddgeeejdhze geeddddgeedddgeedddge dgd Z e e d < dd dd d dddZddZdZedddZdZy) KernelRidgeaKernel ridge regression. Kernel ridge regression (KRR) combines ridge regression (linear least squares with l2-norm regularization) with the kernel trick. It thus learns a linear function in the space induced by the respective kernel and the data. For non-linear kernels, this corresponds to a non-linear function in the original space. The form of the model learned by KRR is identical to support vector regression (SVR). However, different loss functions are used: KRR uses squared error loss while support vector regression uses epsilon-insensitive loss, both combined with l2 regularization. In contrast to SVR, fitting a KRR model can be done in closed-form and is typically faster for medium-sized datasets. On the other hand, the learned model is non-sparse and thus slower than SVR, which learns a sparse model for epsilon > 0, at prediction-time. This estimator has built-in support for multi-variate regression (i.e., when y is a 2d-array of shape [n_samples, n_targets]). Read more in the :ref:`User Guide `. Parameters ---------- alpha : float or array-like of shape (n_targets,), default=1.0 Regularization strength; must be a positive float. Regularization improves the conditioning of the problem and reduces the variance of the estimates. Larger values specify stronger regularization. Alpha corresponds to ``1 / (2C)`` in other linear models such as :class:`~sklearn.linear_model.LogisticRegression` or :class:`~sklearn.svm.LinearSVC`. If an array is passed, penalties are assumed to be specific to the targets. Hence they must correspond in number. See :ref:`ridge_regression` for formula. kernel : str or callable, default="linear" Kernel mapping used internally. This parameter is directly passed to :class:`~sklearn.metrics.pairwise.pairwise_kernels`. If `kernel` is a string, it must be one of the metrics in `pairwise.PAIRWISE_KERNEL_FUNCTIONS` or "precomputed". If `kernel` is "precomputed", X is assumed to be a kernel matrix. Alternatively, if `kernel` is a callable function, it is called on each pair of instances (rows) and the resulting value recorded. The callable should take two rows from X as input and return the corresponding kernel value as a single number. This means that callables from :mod:`sklearn.metrics.pairwise` are not allowed, as they operate on matrices, not single samples. Use the string identifying the kernel instead. gamma : float, default=None Gamma parameter for the RBF, laplacian, polynomial, exponential chi2 and sigmoid kernels. Interpretation of the default value is left to the kernel; see the documentation for sklearn.metrics.pairwise. Ignored by other kernels. degree : float, default=3 Degree of the polynomial kernel. Ignored by other kernels. coef0 : float, default=1 Zero coefficient for polynomial and sigmoid kernels. Ignored by other kernels. kernel_params : dict, default=None Additional parameters (keyword arguments) for kernel function passed as callable object. Attributes ---------- dual_coef_ : ndarray of shape (n_samples,) or (n_samples, n_targets) Representation of weight vector(s) in kernel space X_fit_ : {ndarray, sparse matrix} of shape (n_samples, n_features) Training data, which is also required for prediction. If kernel == "precomputed" this is instead the precomputed training matrix, of shape (n_samples, n_samples). n_features_in_ : int Number of features seen during :term:`fit`. .. versionadded:: 0.24 feature_names_in_ : ndarray of shape (`n_features_in_`,) Names of features seen during :term:`fit`. Defined only when `X` has feature names that are all strings. .. versionadded:: 1.0 See Also -------- sklearn.gaussian_process.GaussianProcessRegressor : Gaussian Process regressor providing automatic kernel hyperparameters tuning and predictions uncertainty. sklearn.linear_model.Ridge : Linear ridge regression. sklearn.linear_model.RidgeCV : Ridge regression with built-in cross-validation. sklearn.svm.SVR : Support Vector Regression accepting a large variety of kernels. References ---------- * Kevin P. Murphy "Machine Learning: A Probabilistic Perspective", The MIT Press chapter 14.4.3, pp. 492-493 Examples -------- >>> from sklearn.kernel_ridge import KernelRidge >>> import numpy as np >>> n_samples, n_features = 10, 5 >>> rng = np.random.RandomState(0) >>> y = rng.randn(n_samples) >>> X = rng.randn(n_samples, n_features) >>> krr = KernelRidge(alpha=1.0) >>> krr.fit(X, y) KernelRidge(alpha=1.0) rNleft)closedz array-like precomputedneitheralphakernelgammadegreecoef0 kernel_params_parameter_constraintsrlinear)rrrrrcX||_||_||_||_||_||_yNr)selfrrrrrrs X/home/alanp/www/video.onchill/myenv/lib/python3.12/site-packages/sklearn/kernel_ridge.py__init__zKernelRidge.__init__s/     *ct|jr|jxsi}n$|j|j|j d}t ||f|jdd|S)N)rrrT)metric filter_params)callablerrrrrr )r"XYparamss r# _get_kernelzKernelRidge._get_kernelsT DKK ''-2F#zzT[[4::VF1WT[[WPVWWr%c$d|jdk(iS)Npairwiser)r)r"s r# _more_tagszKernelRidge._more_tagssDKK=899r%T)prefer_skip_nested_validationc|j||ddd\}}|t|ts t||}|j |}t j |j}d}t|jdk(r|jdd}d}|jdk(}t||||||_ |r|jj|_ ||_|S)aFit Kernel Ridge regression model. Parameters ---------- X : {array-like, sparse matrix} of shape (n_samples, n_features) Training data. If kernel == "precomputed" this is instead a precomputed kernel matrix, of shape (n_samples, n_samples). y : array-like of shape (n_samples,) or (n_samples, n_targets) Target values. sample_weight : float or array-like of shape (n_samples,), default=None Individual weights for each sample, ignored if None is passed. Returns ------- self : object Returns the instance itself. csrcscT) accept_sparse multi_output y_numericFrr)_validate_data isinstancefloatrr-np atleast_1drlenshapereshaperr dual_coef_ravelX_fit_)r"r*y sample_weightKrrCcopys r#fitzKernelRidge.fits,"" qTT# 1  $Z u-M0BM   Q  djj) qww<1  "a AE{{m+0AumTR "oo335DO  r%ct||j|dd}|j||j}t j ||j S)a)Predict using the kernel ridge model. Parameters ---------- X : {array-like, sparse matrix} of shape (n_samples, n_features) Samples. If kernel == "precomputed" this is instead a precomputed kernel matrix, shape = [n_samples, n_samples_fitted], where n_samples_fitted is the number of samples used in the fitting for this estimator. Returns ------- C : ndarray of shape (n_samples,) or (n_samples, n_targets) Returns predicted values. r3F)r6reset)rr:r-rDr=dotrB)r"r*rGs r#predictzKernelRidge.predictsN    u  M   Q ,vva))r%)rr!)__name__ __module__ __qualname____doc__r rr setr keysr)dictr__annotations__r$r-r0rrIrMr%r#rrsrj4D8,G s9499;< N O  4D8$?D!T&9:4tI>? $D ++"X:5*6*X*r%r)rQnumbersrnumpyr=baserrrrlinear_model._ridger metrics.pairwiser r utils._param_validationr r utils.validationrrrrVr%r#r^s5 OO7I9C\*"NM\*r%