scikit-learn/scikit-learn — pull request #1227 by fabianp (2012-10-09 12:29:10+00:00)
Title: ENH: Consider order in X for IsotonicRegression.

Before, IsotonicRegression assumed X was an increasing sequence. This
allows to shuffle both X, y (see the test) and obtain the same
result. This makes IsotonicRegression behave more like a standard
Regression (which is what I would expect).