1.15. Isotonic regression¶ The class IsotonicRegression fits a non-decreasing real function to 1-dimensional data. It solves the following problem: minimize \(\sum_i w_i (y_i - \hat{y}_i)^2\) subject to \(\hat{y}_i \le \hat{y}_j\) whenever \(X_i \le X_j\), where the weights \(w_i\) are strictly positive, and both X and y are arbitrary real quantities. The increasing parameter changes the constrain