[Pkg-octave-devel] Errors in octave-signal's testsuite

[Bastien ROUCARIES]

Or this very good paper
hal.archives-ouvertes.fr/docs/00/28/14/29/PDF/floating-point-article.pdf

with recent gcc -fexcess-precision=strict will fix this issue if
compiled in pure c (unfortunatly not implemented in c++)

see also http://www.vinc17.org/research/extended.en.html

(Vincent Lefèvre is a well lnow debian contributor and a world top
class researcher is this kind of topic)

Bastien

On Fri, Mar 16, 2012 at 6:00 PM, Bastien ROUCARIES
<roucaries.bastien+octave at gmail.com> wrote:
> On Fri, Mar 16, 2012 at 5:56 PM, Bastien ROUCARIES
> <roucaries.bastien+octave at gmail.com> wrote:
>> On Thu, Mar 15, 2012 at 12:48 AM, Rafael Laboissiere
>> <rafael at laboissiere.net> wrote:
>>> * Thomas Weber <tweber at debian.org> [2012-03-14 19:56]:
>>>
>>>> On Wed, Mar 14, 2012 at 08:58:20AM +0100, Rafael Laboissiere wrote:
>>>> > Since I get the same values for a and b as yours, the only conceivable
>>>> > source of divergence is the filter function.  What does "which filter"
>>>> > yield for you?
>>>>
>>>> I've put a .mat file with the variables after running your commands at
>>>> http://people.debian.org/~tweber/logs/pei_tseng_notch.mat.lzma
>>>>
>>>> Can you compare the variables with your workspace?
>>>
>>> As I suspected, the divergence between your data and mine happen in
>>> the filter function.  I assume that we are using the same one, in
>>> /usr/lib/i386-linux-gnu/octave/3.6.1/oct/i486-pc-linux-gnu/filter.oct
>>>
>>> The only difference that I can imagine between our systems is the
>>> precision.  I am using a 32-bits system and I guess you are using a
>>> 64-bit system.  Which is the value of eps in your system?
>>
>> smell like intel fpu 80 bits precision compared to 64 bits. Well known
>> problem in numeric computation
>>
>> Bastien
>
> See     http://www.validgh.com/goldberg/paper.ps
> http://www.wrcad.com/linux_numerics.txt
>
>>> Rafael
>>>
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