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- From: ak.miller at auckland.ac.nz (Andrew Miller)
- Subject: [cellml-dev] PCEnv under Vista 64-bit, XP 32-bit and XP 64-bit
- Date: Wed, 26 Sep 2007 17:40:10 +1200
Randall Britten wrote:
> Hi
>
> I wonder if we should be putting these kinds of discussions in the tracker
> anyway. The Cmgui project use their tracker that way, and it allows them to
> build up a knowledge base. What do you think?
>
Hi,
I think that it would be a good idea to do this, except that Alan
currently can't access the tracker and so we obviously can't do this
until that issue is resolved.
Best regards,
Andrew
> Regards,
> Randall
>
> -----Original Message-----
> From: Alan Garny [mailto:alan.garny at dpag.ox.ac.uk]
> Sent: Wednesday, 26 September 2007 5:19 p.m.
> To: 'Andrew Miller'
> Cc: 'Randall Britten'
> Subject: RE: PCEnv under Vista 64-bit, XP 32-bit and XP 64-bit
>
> Hi Andrew,
>
>
>>> Anyway, I have been doing some tests on different Windows platforms
>>> and came across something rather worrying in my opinion. Basically, I
>>> get different results using different operating systems.
>>>
>>> I ran the attached CellML model using the official version of PCEnv
>>> (i.e. 0.2) under:
>>>
>>> - Vista Ultimate 64-bit (my main operating system),
>>>
>>> - XP Pro 32-bit (in a VM), and
>>>
>>> - XP Pro 64-bit (in a VM).
>>>
>>> I cannot recall for certain the parameters I used for the simulation,
>>> but they were definitely the same in all cases. The simulation
>>> finished, I exported the results and manually removed all the data,
>>> but the ones about the transmembrane potential. As you can see from
>>> the attachment, the results I got are different. I understand that
>>> this might be the case for various reasons (e.g. gcc generates a
>>> slightly different code on each operating system, the data are not
>>> necessarily generated at the exact same time). Still, if you plot
>>> those data, you cannot help but notice that the results are indeed
>>> different.
>>>
>>> I have the feeling that this might because of gcc (or any compiler for
>>> that matter), but I cannot currently test that hypothesis and was
>>> wondering whether you could at least confirm to me that you are also
>>> experiencing the same behaviour?
>>>
>>>
>> I don't actually have a 64-bit Windows system available to me, so I
>> can't confirm this. However, it is worth noting that different platforms
>> have different FPU behaviour and differences in precision. If this is
>> making a major difference to the end-point then this probably raises
>> concerns about the stability of the model under the integrator used.
>>
>
> Fair point. I will try to run the same kind of test using different models
> to see what we get. Note, though, that even between Vista Ultimate 64-bit
> and XP 64-bit, I got different results...
>
> Alan.
>
>
>
- [cellml-dev] PCEnv under Vista 64-bit, XP 32-bit and XP 64-bit, Andrew Miller, 09/26/2007
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