[ADMB Users] Please test updated installation documentation - Bug still not fixed
davef at otter-rsch.com
Thu Nov 21 19:01:30 PST 2013
On 13-11-21 06:29 PM, Alex Campbell wrote:
I'm not sure I understand this.
what does this mean?
mceval output inconsistent with mcmc display"
I know I wrote the mcmc stuff really fast and wanted some output that I
could plot with gnuplot
for a useless meeting in 1992.
It worked fine with a good model, but not with a "bad" model. The
mceval stuff was really meant
to supercede it i.e if you got good results with the display fine, but
the real output was intended to
be the mceval stuff.
I wonder what happens with R if you write a model with unidentifiable
There is a standard thing I use (or used to use back when I was still
alive) I would put a small quadratic penalty
on all the parameters when the problem seemed degenerate. with a little
bit of tuning it was usually
possible to find where the unidentifiability was.
Anyway if you are trying to convince a someone of the value of ADMB, I
can think of better ways than
trying to fit a model with unidentifiable parameters.
> I posted on this a couple of years ago. See "mceval output
> inconsistent with mcmc display". The last word there is me saying I've
> figured it out and I'll send you the code to reproduce the issue off
> list. Can't remember if I did, and don't have access to those emails
> to check. I think I did send it to you and never heard back. I assumed
> since no one else had come across this since that time it might have
> been resolved with updates to the mingw compiler. But no. Came across
> it again about six months ago on another model, ADMB version 10 i
> think or maybe 10.1. I was in the process of winning over a colleague
> to the ADMB cause and had to basically say well its great but its
> broken on windows. We ran the same code, same inputs on linux and it
> diagnosed the unidentifiability (can't remember the exact message but
> i assume it was telling us that the hessian was singular to machine
> precision). We had an unidentifiable virgin recruitment in one spatial
> region, which made sense in hindsight. If you can't find the code and
> inputs I sent you in June-July 2011 (or if I didn't?) I can dig around
> for the more recent model. Can't remember if I've checked this out on
> a visual studio compiler but I have a hunch the issue is mingw not
> windows in general.
> On Fri, Nov 22, 2013 at 1:19 AM, dave fournier <davef at otter-rsch.com
> <mailto:davef at otter-rsch.com>> wrote:
> My experience of the mingw compiler is that with it ADMB fails to
> diagnose singular or near singular hessians. This is a minefield
> for inexperienced users and in my opinion it should not be
> supported. Has no one else seen this issue?
> That seems highly unlikely in the sense that the mingw compiler
> would be different
> from any other compiler in this manner. Do you have an example?
> Users mailing list
> Users at admb-project.org <mailto:Users at admb-project.org>
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