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

[Bastien ROUCARIES]

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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