Re: [Help-gsl] eigen test fails on 32-bit (x86) Linux

[Patrick Alken]

This should be fixed on the git repository (see bug #39055), though it 
may be that the tolerances need adjusting for your system.

On 08/18/2014 04:02 PM, address@hidden wrote:
> There is another test failure of a similar kind, but now without any -O
> flags:
>
> $ ./configure CFLAGS=
> $ make
> $ poly/test
> FAIL: z1.real, 15th-order polynomial (-0.999999999999994227 observed vs 1
> expected) [159]
> FAIL: z2.real, 15th-order polynomial (1.00000005616458409 observed vs -1
> expected) [161]
> FAIL: z13.real, 15th-order polynomial (1.99999988977862886 observed vs 2
> expected) [183]
> FAIL: z14.real, 15th-order polynomial (2.00000011022135338 observed vs 2
> expected) [185]
>
> Victor
>
>
> On Mon, Aug 18, 2014 at 2:48 PM, address@hidden <
> address@hidden> wrote:
>
> > Thanks for quick responses guys.
> >
> > Patrick, please find attached the patch that implements your suggestion
> > which does fix the test failures. I've
> > reused GSL_EIGEN_SORT_VAL_{ASC,DESC}, that were previously unused for
> > complex numbers, for the new type of comparison.
> >
> > Victor
> >
> >
> >
> > On Mon, Aug 18, 2014 at 12:21 PM, Patrick Alken <
> > address@hidden> wrote:
> >
> > > GSL is already sorting the eigenvalues based on magnitude, so the problem
> > > seems to be that with the extra -O3 optimization, the gsl_eigen_gen and
> > > gsl_eigen_genv routines are producing slightly different results, leading
> > > to a different sorting order. One way to fix this would be to sort by real
> > > part first and then by imaginary part, but it may be a little while until I
> > > can look into this further.
> > >
> > > Patrick
> > >
> > >
> > > On 08/18/2014 12:59 PM, Martin Jansche wrote:
> > >
> > > > I'm not sure if GSL makes any guarantees about the direction of
> > > > eigenvectors. It looks like the test might pass if one only looks at the
> > > > magnitude of the values. Perhaps the test could be made robust against
> > > > sign
> > > > changes by looking at absolute values.
> > > >
> > > >
> > > >
> > > > On Mon, Aug 18, 2014 at 1:53 PM, address@hidden <
> > > > address@hidden> wrote:
> > > >
> > > >   Hello,
> > > > > I noticed that eigen test fails on 32-bit Linux (x86) when compiled with
> > > > > -O3 flag:
> > > > >
> > > > > $ ./configure CFLAGS="-O3"
> > > > > $ make
> > > > > $ eigen/test
> > > > > FAIL: gen, direct eigenvalue(4) imag, random (-0.481216772353650846
> > > > > observed vs 0.481216772353650846 expected) [877968]
> > > > > FAIL: gen, direct eigenvalue(5) imag, random (0.481216772353650901
> > > > > observed
> > > > > vs -0.481216772353650846 expected) [877970]
> > > > > FAIL: gen, direct eigenvalue(15) imag, random (6.85872455924790447
> > > > > observed
> > > > > vs -6.85872455924790536 expected) [877990]
> > > > > FAIL: gen, direct eigenvalue(16) imag, random (-6.85872455924790536
> > > > > observed vs 6.85872455924790625 expected) [877992]
> > > > >
> > > > > I'm using GSL version 1.16, 32-bit Ubuntu 10.04 and GCC 4.4.3.
> > > > >
> > > > > Best regards,
> > > > > Victor