[ADMB Users] Error message

[John Sibert]

John,
It is a bit hard to tell what is provoking this message without seeing 
more of the screen output from ADMB.

The message may signal that there is an error in the derivatives 
somewhere. You can check this by invoking the derivative checker. Run 
you model with the -dd flag, ie
my_model -dd N
where N is a bit less than the number of function evaluations when it 
quites with the dreaded ialph=1 error. 1e-4 is a good step size.

It could also mean that the data you are using are not very informative 
about your model. If that is the case, you probably need to rethink you 
model. Check for confounded parameters. Don't make them all active in 
the first phase.
 
Hope this helps. Let me know what happens.
John

John wrote:
>
> Hey
>
>  
>
> I just have a brief question regarding a persistent error message that 
> I am getting from part of my ADMB code. It looks as follows:
>
>  
>
> Function minimizer: Step size  too small -- ialph=1
>
>  
>
> Any help in explaining the situation would be of great help!
>
>  
>
> Thank you in advance,
>
> *John E. Murray*
>
> *OLRAC*
>
> *Silvermine House, Steenberg Office Park.*
>
> *Tokai 7945, Cape Town, South Africa.*
>
> *Office +27 (0)21 702 4111*
>
> *Fax +27 (0)21 702 4333*
>
> *Email - john at olrac.com*
>
>  
>
>  
>
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-- 
John Sibert
Emeritus Researcher, SOEST
University of Hawaii at Manoa

Visit the ADMB project http://admb-project.org/