4.2. Migrating to v0.3 from v0.2

Up to version 0.2, Fairlearn contained only the exponentiated gradient method. The Fairlearn repository now has a more comprehensive scope and aims to incorporate other methods. The same exponentiated gradient technique is now the class fairlearn.reductions.ExponentiatedGradient. While in the past exponentiated gradient was invoked via

import numpy as np
from fairlearn.classred import expgrad
from fairlearn.moments import DP

estimator = LogisticRegression()  # or any other estimator
exponentiated_gradient_result = expgrad(X, sensitive_features, y, estimator, constraints=DP())
positive_probabilities = exponentiated_gradient_result.best_classifier(X)
randomized_predictions = (positive_probabilities >= np.random.rand(len(positive_probabilities))) * 1

the equivalent operation is now

from fairlearn.reductions import ExponentiatedGradient, DemographicParity

estimator = LogisticRegression()  # or any other estimator
exponentiated_gradient = ExponentiatedGradient(estimator, constraints=DemographicParity())
exponentiated_gradient.fit(X, y, sensitive_features=sensitive_features)
randomized_predictions = exponentiated_gradient.predict(X)