test_extract_xi failing on nightly builds

test_extract_xi failing for MB_PYTHON_VERSION=3.6 PLAT=i686 and MB_PYTHON_VERSION=3.7 PLAT=i686

https://travis-ci.org/MacPython/scikit-learn-wheels/jobs/525429182 https://travis-ci.org/MacPython/scikit-learn-wheels/jobs/525429184

[jnothman]

The shuffling order cannot be the reason this test is failing on some platforms, since numpy’s random number generator should be more-or-less cross platform (when generating small ints, certainly).

Numeric issues are a more likely culprit. But without having a hack on that platform, it’s hard to work out where they may come from.

[qinhanmin2014]

This is obviously a typo in the paper. Since the steep up region is monotone, the minimum with < would always be sU, the start of the steep-up region. With a > this is consistent with the first case.

Thanks, we’ll correct it.