RuntimeWarning: invalid value encountered in multiply...

[kellymarchisio]

Most times I run this script (though not every time), I get:
.../python2.7/site-packages/scipy/stats/_distn_infrastructure.py:1910: RuntimeWarning: invalid value encountered in multiply lower_bound = self.a * scale + loc
.../python2.7/site-packages/scipy/stats/_distn_infrastructure.py:1911: RuntimeWarning: invalid value encountered in multiply upper_bound = self.b * scale + loc
[['0.584945', '0.000000', '(nan,nan)']]
due to std passed to scipy.stats.norm.interval(0.95, loc=mean, scale=std) in get_gleu_stats being 0.0 (because the scores are either all the same, or a list of size 1).

[keisks]

Yes, if there's a single reference (or all the references are the same), we get this warning.
This is not a bug, but I'll turn the warning off.