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

[address@hidden]

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
>>>>
>>>>
>>
>>
>