[ADMB Users] a difference in estimates between versions?

[Derek Seiple]

What do you mean by "small but obvious" can you give an example?

If by small you mean they are the same out to say 7 decimal places,
this is to be somewhat expected. In moving from version 9 to version
10 several of the mathematical functions had to be changes for
licensing reasons. Having slightly different algorithms could result
in slightly different round off, and as Ian said a slightly different
path through the likelihood surface. If that is the case then I'm not
sure you could say one is more reliable than the other, per say.

If they are big changes, then that might be worth looking into.

Derek

On Tue, Oct 4, 2011 at 7:24 PM, Saang-Yoon <shyunuw at gmail.com> wrote:
> Ian.
> Thank you very much for your prompt response.  It is always nice to
> hear from acquaintace from a long distance.   Getting back to the
> inquiry topic, then which version is more reliable?   The difference
> is small but obvious.  Especially the difference in estimates of
> 'standard errors' are more obvious.
> Saang-Yoon
>
> On Oct 4, 7:09 pm, Ian Taylor <Ian.Tay... at NOAA.gov> wrote:
>> Hi Saang-Yoon,
>> It sounds from your email like you're changing versions AND changing
>> from 32bit to 64bit. I've found that 32 and 64 provide very slightly
>> different results, which I presume is due to small differences in the
>> precision of the derivative calculations and thus a different path
>> through the likelihood surface and a slightly different point when the
>> convergence criterion gets met.
>>
>> You might try comparing 32 to 32 between versions or 32 to 64 within one
>> version to check whether this is a factor in the change you've observed.
>> -Ian
>>
>> On 10/04/2011 03:51 PM, Saang-Yoon wrote:
>>
>>
>>
>> > Hello, all.
>>
>> > I would like to report differences in estimates between the latest
>> > version (admb-ide-452-1 (64bit)) and the previous version (admb-
>> > ide-450-1).   Today I found differences in estimates between versions
>> > from my class where I used the latest version and the other folks all
>> > used the previous version.  Applying the same TPL and DAT files, my
>> > results (e.g., STD file) are slightly but obviously different from the
>> > others whose values are the same among them.   In the two versions,
>> > estimation were all successful including Hessian matrix elements.
>>
>> > I wonder about why.  More importantly I wonder which version is
>> > reliable.
>>
>> > If you are skeptical of our finding, then please apply a DAT file and
>> > a TPL file that has a "non" linear model to the different versions, or
>> > request me to send you the DAT and TPL files.
>>
>> > Thank you,
>>
>> > Saang-Yoon
>> > _______________________________________________
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>> > Us... at admb-project.org
>> >http://lists.admb-project.org/mailman/listinfo/users
>>
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