LogisticRegression

class cuml.linear_model.LogisticRegression(

*,

penalty='l2',

tol=0.0001,

C=1.0,

fit_intercept=True,

class_weight=None,

max_iter=1000,

linesearch_max_iter=50,

l1_ratio=None,

solver='qn',

lbfgs_memory=5,

penalty_normalized=True,

verbose=False,

output_type=None,

)

Logistic Regression classifier.

LogisticRegression is a linear model that is used to model probability of occurrence of certain events, for example probability of success or fail of an event.

Parameters:

penalty{‘l1’, ‘l2’, ‘elasticnet’, None}, default=’l2’

Specifies the penalty term to use. 'l1' and 'l2' will use an L1 or L2 penalty, respectively. 'elasticnet' will use both an L1 and L2 penalty. None will not use a penalty.

tolfloat, default=1e-4

Tolerance for stopping criteria. The exact stopping conditions depend on the chosen solver. Check the solver’s documentation for more details:

• Quasi-Newton (L-BFGS/OWL-QN)

Cfloat, default=1.0

Inverse of regularization strength; must be a positive float.

fit_interceptbool, default=True

Specifies if a constant (a.k.a bias or intercept) should be added to the decision function. Note that, just like in Scikit-learn, the bias will not be regularized.

class_weightdict or ‘balanced’, default=None

By default all classes have a weight one. However, a dictionary can be provided with weights associated with classes in the form {class_label: weight}. 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)). Note that these weights will be multiplied with sample_weight (passed through the fit method) if sample_weight is specified.

max_iterint, default=1000

Maximum number of iterations taken for the solvers to converge.

linesearch_max_iterint, default=50

Max number of linesearch iterations per outer iteration used in the lbfgs and owl QN solvers.

l1_ratiofloat or None, default=None

The Elastic-Net mixing parameter, with 0 <= l1_ratio <= 1

solver{‘qn’}, default=’qn’

Algorithm to use in the optimization problem. Currently only qn is supported, which automatically selects either L-BFGS or OWL-QN depending on the conditions of the l1 regularization described above.

lbfgs_memory: int, default = 5

Rank of the lbfgs inverse-Hessian approximation. Method will use O(lbfgs_memory * n_features) memory.

penalty_normalizedbool, default=True

By default the penalty term is divided by the sample size. Set to False to skip this behavior.

verboseint or boolean, default=False

Sets logging level. It must be one of cuml.common.logger.level_*. See Verbosity Levels for more info.

output_type{None, ‘input’, ‘cupy’, ‘numpy’, ‘cudf’, ‘pandas’}, default=None

Return results and set estimator attributes to the indicated output type. If None, the output type set at the module level (cuml.global_settings.output_type) will be used. See Output Data Type Configuration for more info.

Attributes:

coef_: array, shape=(n_classes, n_features) or (n_classes, n_features)

The estimated coefficients for the logistic regression model.

intercept_: array, shape=(1,) or (n_classes,)

The independent term. If fit_intercept is False, will be 0.

n_iter_: array, shape (1,)

The number of iterations taken for the solvers to converge.

classes_np.ndarray, shape=(n_classes,)

Array of the class labels.

Methods

fit(X, y[, sample_weight])	Fit the model with X and y.
predict(X)	Predicts the y for X.
predict_log_proba(X)	Predicts the log class probabilities for each class in X
predict_proba(X)	Predicts the class probabilities for each class in X

Notes

cuML’s LogisticRegression uses a different solver that the equivalent Scikit-learn, except when there is no penalty and solver=lbfgs is used in Scikit-learn. This can cause (smaller) differences in the coefficients and predictions of the model, similar to using different solvers in Scikit-learn.

For additional information, see Scikit-learn’s LogisticRegression.

Examples

>>> import cuml
>>> import cupy as cp
>>> X = cp.array([[1, 1], [1, 2], [2, 2], [2, 3]])
>>> y = cp.array([0, 0, 1, 1])
>>> model = cuml.LogisticRegression().fit(X, y)
>>> model.predict(X)
array([0, 0, 1, 1])

as_sklearn()

Convert this estimator into an equivalent scikit-learn (or scikit-learn extension) estimator.

Returns:

sklearn.base.BaseEstimator

A scikit-learn compatible estimator instance that mirrors the trained state of the current estimator.

decision_function(X)

Predict confidence scores for samples.

Parameters:

Xarray-like (device or host) shape = (n_samples, n_features)

Dense or sparse matrix with dtype float32 or float64. Acceptable dense formats: CUDA array interface compliant objects like CuPy, cuDF DataFrame/Series, NumPy ndarray and Pandas DataFrame/Series.

Returns:

scorescuDF, CuPy or NumPy object depending on cuML’s output type configuration, shape = (n_samples,) or (n_samples, n_classes)

Confidence scores

For more information on how to configure cuML’s output type, refer to: Output Data Type Configuration.

fit(

X,

y,

sample_weight=None,

) → LogisticRegression

Fit the model with X and y.

Parameters:

Xarray-like (device or host) shape = (n_samples, n_features)

Dense or sparse matrix with dtype float32 or float64. Acceptable dense formats: CUDA array interface compliant objects like CuPy, cuDF DataFrame/Series, NumPy ndarray and Pandas DataFrame/Series.

yarray-like (device or host) shape = (n_samples, 1)

Dense matrix with dtype float32 or float64. Acceptable formats: CUDA array interface compliant objects like CuPy, cuDF DataFrame/Series, NumPy ndarray and Pandas DataFrame/Series.

sample_weightarray-like (device or host) shape = (n_samples,), default=None

The weights for each observation in X. If None, all observations are assigned equal weight. Acceptable formats: CUDA array interface compliant objects like CuPy, cuDF DataFrame/Series, NumPy ndarray and Pandas DataFrame/Series.

classmethod from_sklearn(model)

Create a cuml estimator from a scikit-learn estimator.

Parameters:

modelsklearn.base.BaseEstimator

A compatible scikit-learn (or scikit-learn extension) estimator.

Returns:

cls

A new instance of this cuml estimator class that mirrors the state of the input estimator.

Notes

output_type of the estimator is set to “numpy” by default, as these cannot be inferred from training arguments. If something different is required, then please use cuml’s output_type configuration utilities.

get_params(deep=True)

Returns a dict of all params owned by this class. If the child class has appropriately overridden the _get_param_names method and does not need anything other than what is there in this method, then it doesn’t have to override this method

predict(X)

Predicts the y for X.

Parameters:

Xarray-like (device or host) shape = (n_samples, n_features)

Dense or sparse matrix with dtype float32 or float64. Acceptable dense formats: CUDA array interface compliant objects like CuPy, cuDF DataFrame/Series, NumPy ndarray and Pandas DataFrame/Series.

Returns:

predscuDF, CuPy or NumPy object depending on cuML’s output type configuration, shape = (n_samples, 1)

Predicted values

For more information on how to configure cuML’s output type, refer to: Output Data Type Configuration.

predict_log_proba(X)

Predicts the log class probabilities for each class in X

Parameters:

Xarray-like (device or host) shape = (n_samples, n_features)

Dense or sparse matrix with dtype float32 or float64. Acceptable dense formats: CUDA array interface compliant objects like CuPy, cuDF DataFrame/Series, NumPy ndarray and Pandas DataFrame/Series.

Returns:

probscuDF, CuPy or NumPy object depending on cuML’s output type configuration, shape = (n_samples, n_classes)

Log probabilities per class for each sample.

For more information on how to configure cuML’s output type, refer to: Output Data Type Configuration.

predict_proba(X)

Predicts the class probabilities for each class in X

Parameters:

Xarray-like (device or host) shape = (n_samples, n_features)

Dense or sparse matrix with dtype float32 or float64. Acceptable dense formats: CUDA array interface compliant objects like CuPy, cuDF DataFrame/Series, NumPy ndarray and Pandas DataFrame/Series.

Returns:

probscuDF, CuPy or NumPy object depending on cuML’s output type configuration, shape = (n_samples, n_classes)

Probabilities per class for each sample.

For more information on how to configure cuML’s output type, refer to: Output Data Type Configuration.

score(X, y, sample_weight=None, **kwargs)

Scoring function for classifier estimators based on mean accuracy.

Parameters:

Xarray-like (device or host) shape = (n_samples, n_features)

Dense matrix with dtype float32 or float64. Acceptable formats: CUDA array interface compliant objects like CuPy, cuDF DataFrame/Series, NumPy ndarray and Pandas DataFrame/Series.

yarray-like (device or host) shape = (n_samples, 1)

Dense matrix with dtype float32 or float64. Acceptable formats: CUDA array interface compliant objects like CuPy, cuDF DataFrame/Series, NumPy ndarray and Pandas DataFrame/Series.

sample_weightarray-like (device or host) shape = (n_samples,), default=None

The weights for each observation in X. If None, all observations are assigned equal weight. Acceptable formats: CUDA array interface compliant objects like CuPy, cuDF DataFrame/Series, NumPy ndarray and Pandas DataFrame/Series.

Returns:

scorefloat

Accuracy of self.predict(X) wrt. y (fraction where y == pred_y)

set_params(**params)

Accepts a dict of params and updates the corresponding ones owned by this class. If the child class has appropriately overridden the _get_param_names method and does not need anything other than what is, there in this method, then it doesn’t have to override this method