Re: [Pkg-octave-devel] [RFU] Several packages for jessie

[Rafael Laboissiere <rafael@laboissiere.net>]

* Sébastien Villemot <sebastien@debian.org> [2013-05-20 14:46]:
> I uploaded all of them to unstable, except octave-image and octave-nurbs 
> which have failing tests. [snip]

I am revisiting the issue with octave-image.  According to your build 
log, one of the failures you observed is the following one:

    [imnoise]
      ***** assert(var(imnoise(ones(10)/2,'speckle')(:)),0.01,0.005) # probabilistic
    !!!!! test failed
    assert (var (imnoise (ones (10) / 2, 'speckle') (:)),0.01,0.005) expected
     0.010000
    but got
     0.015648
    maximum absolute error 0.00564816 exceeds tolerance 0.005

This test is probabilistic (as it is announced in the comment above). I 
ran a quick test to check the variability of the result:

    n = 10000;
    v = zeros (1, n);
    for i = 1 : n
         v (i) = var (imnoise (ones (10) / 2, 'speckle') (:));
    endfor
    length (find (abs (v - 0.01) > 0.005)) / n

The last line yields 0.0016.  This means that we got hit by an event with 
approximately 0.16% of happening.  This is a very low probability, but it 
is greater than zero and, indeed, has bitten us.

I am wondering how we should proceed about these probabilistic tests 
in our packages.

Rafael