Re: PSPP-BUG: pspp bug

[Ben Pfaff]

That sounds fine, thank you.

John Darrington <address@hidden> writes:

> OK, I had a look at this closer.   The root cause is that the
> example data are very nearly linearly correlated.  Hence the
> correlation matrix has a determinant close to zero and thus, the
> KMO and Bartlett measures are very unstable.
>
> Since they don't have any relevance to the bug being tested, for 
> now I have simply removed them from the test.
>
>
> J'
>
> On Thu, Apr 05, 2012 at 10:12:53PM -0700, Ben Pfaff wrote:
>      When we looked at this in IRC, I think we were looking at the
>      wrong value.  You were talking about log(0) but that's involved
>      in "Bartlett's Test of Sphericity" not in "Kaiser-Meyer-Olkin
>      Measure of Sampling Adequacy".
>      
>      I added
>            printf ("sum_ssq_r=%e sum_ssq_a=%e\n", sum_ssq_r, sum_ssq_a);
>      as line 1870 of factor.c and got:
>              sum_ssq_r=3.472064e+35 sum_ssq_a=1.036522e-30
>      so that the calculation sum_ssq_r /  (sum_ssq_r + sum_ssq_a) is
>      basically x / (x + 0) == 1, which seems reasonable.  What do you
>      see when you add that line?
>      
>      John Darrington <address@hidden> writes:
>      
>      > I'll take a look at it.
>      >
>      > On Wed, Apr 04, 2012 at 09:17:17AM -0700, Ben Pfaff wrote:
>      >      That seems bad.  "1.00" and NaN are pretty different.  Do you
>      >      think it's worth looking into the calculations, or should we just
>      >      ignore this difference as we have others?
>      >      
>      >      John Darrington <address@hidden> writes:
>      >      
>      >      > My system fails the new test:
>      >      >
>      >      > 395. factor.at:1803: testing FACTOR /ROTATION=NOROTATE ...
>      >      > ../../tests/factor.at:1821: pspp -O format=csv 
> factor-norotate.sps
>      >      > --- -   2012-04-04 11:18:24.388115600 +0100
>      >      > +++ 
> /home/Darringt/.p/P/UTP_00/ClearQuest/tests/testsuite.dir/at-groups/395/stdout
>       2012-04-04 11:18:23.366814100 +0100
>      >      > @@ -7,7 +7,7 @@
>      >      >  TRAIT5,7.29,2.66,7
>      >      >  
>      >      >  Table: KMO and Bartlett's Test
>      >      > -Kaiser-Meyer-Olkin Measure of Sampling Adequacy,,1.00
>      >      > +Kaiser-Meyer-Olkin Measure of Sampling Adequacy,,NaN
>      >      >  Bartlett's Test of Sphericity,Approx. Chi-Square,NaN
>      >      >  ,df,10
>      >      >  ,Sig.,NaN
>      >      > 395. factor.at:1803:  FAILED (factor.at:1821)
>      >      >
>      >      >
>      >      > On Tue, Apr 03, 2012 at 10:00:28PM -0700, Ben Pfaff wrote:
>      >      >      Thank you very much for the bug report.  I reproduced the 
> bug and
>      >      >      fixed this on the PSPP "master" branch.
>      >      >      -- 
>      >      >      Ben Pfaff 
>      >      >      http://benpfaff.org
>      >      >      
>      >      >      _______________________________________________
>      >      >      Bug-gnu-pspp mailing list
>      >      >      address@hidden
>      >      >      https://lists.gnu.org/mailman/listinfo/bug-gnu-pspp
>      >      
>      >      -- 
>      >      Ben Pfaff 
>      >      http://benpfaff.org
>      
>      -- 
>      Ben Pfaff 
>      http://benpfaff.org

-- 
Ben Pfaff 
http://benpfaff.org