GaussianNB

Gaussian Naive Bayes.

A Gaussian distribution \(G_{cf}\) is maintained for each class \(c\) and each feature \(f\). Each Gaussian is updated using the amount associated with each feature; the details can be be found in proba.Gaussian. The joint log-likelihood is then obtained by summing the log probabilities of each feature associated with each class.

Examples

>>> from river import naive_bayes
>>> from river import stream
>>> import numpy as np

>>> X = np.array([[-1, -1], [-2, -1], [-3, -2], [1, 1], [2, 1], [3, 2]])
>>> Y = np.array([1, 1, 1, 2, 2, 2])

>>> model = naive_bayes.GaussianNB()

>>> for x, y in stream.iter_array(X, Y):
...     _ = model.learn_one(x, y)

>>> model.predict_one({0: -0.8, 1: -1})
1

Methods

clone

Return a fresh estimator with the same parameters.

The clone has the same parameters but has not been updated with any data. This works by looking at the parameters from the class signature. Each parameter is either - recursively cloned if it's a River classes. - deep-copied via copy.deepcopy if not. If the calling object is stochastic (i.e. it accepts a seed parameter) and has not been seeded, then the clone will not be idempotent. Indeed, this method's purpose if simply to return a new instance with the same input parameters.

joint_log_likelihood

Compute the unnormalized posterior log-likelihood of x.

The log-likelihood is log P(c) + log P(x|c).

Parameters

• x (dict)

joint_log_likelihood_many

Compute the unnormalized posterior log-likelihood of x in mini-batches.

The log-likelihood is log P(c) + log P(x|c).

Parameters

• X (pandas.core.frame.DataFrame)

learn_one

Update the model with a set of features x and a label y.

Parameters

• x (dict)
• y (Union[bool, str, int])

Returns

Classifier: self

p_class

predict_many

Predict the labels of a DataFrame X.

Parameters

• X (pandas.core.frame.DataFrame)

Returns

Series: Series of predicted labels.

predict_one

Predict the label of a set of features x.

Parameters

• x (dict)

Returns

typing.Union[bool, str, int]: The predicted label.

predict_proba_many

Return probabilities using the log-likelihoods in mini-batchs setting.

Parameters

• X (pandas.core.frame.DataFrame)

predict_proba_one

Return probabilities using the log-likelihoods.

Parameters

• x (dict)