[SciPy-Dev] Warnings raised (from fit in scipy.stats)

Skipper Seabold jsseabold@gmail....
Fri Jun 11 11:45:05 CDT 2010


Since the raising of warning behavior has been changed (I believe), I
have been running into a lot of warnings in my code when say I do
something like

In [120]: from scipy import stats

In [121]: y = [-45, -3, 1, 0, 1, 3]

In [122]: v = stats.norm.pdf(y)/stats.norm.cdf(y)
Warning: invalid value encountered in divide

Sometimes, this is useful to know.  Sometimes, though, it's very
disturbing when it's encountered in some kind of iteration or
optimization.  I have been using numpy.clip to get around this in my
own code, but when it's buried a bit deeper, it's not quite so simple.

Take this example.

In [123]: import numpy as np

In [124]: np.random.seed(12345)

In [125]: B = 6.0

In [126]: x = np.random.exponential(scale=B, size=5000)

In [127]: from scipy.stats import expon

In [128]: expon.fit(x)

<dozens of warnings clipped>

Out[128]: (0.21874043533906118, 5.7122829778172939)

The fit is achieved by fmin (as far as I know, since disp=0 in the
rv_continuous.fit...), but there are a number of warnings emitted.  Is
there any middle ground to be had in these type of situations via
context management perhaps?

Should I file a ticket?

Skipper


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