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<div class="moz-cite-prefix">On 13-11-21 06:29 PM, Alex Campbell
wrote:<br>
<br>
I'm not sure I understand this.<br>
<br>
what does this mean?<br>
<br>
mceval output inconsistent with mcmc display"<br>
<br>
<br>
I know I wrote the mcmc stuff really fast and wanted some output
that I could plot with gnuplot<br>
for a useless meeting in 1992.<br>
It worked fine with a good model, but not with a "bad" model. The
mceval stuff was really meant<br>
to supercede it i.e if you got good results with the display fine,
but the real output was intended to<br>
be the mceval stuff.<br>
<br>
I wonder what happens with R if you write a model with
unidentifiable parameters?<br>
<br>
There is a standard thing I use (or used to use back when I was
still alive) I would put a small quadratic penalty<br>
on all the parameters when the problem seemed degenerate. with a
little bit of tuning it was usually<br>
possible to find where the unidentifiability was.<br>
<br>
Anyway if you are trying to convince a someone of the value of
ADMB, I can think of better ways than<br>
trying to fit a model with unidentifiable parameters.<br>
<br>
<br>
<br>
</div>
<blockquote
cite="mid:CAN2TOfYp4LYVnwyR1GmWBfr2G3aNeND8a+T2=O+oD_9tsp33SQ@mail.gmail.com"
type="cite">
<div dir="ltr">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.<br>
</div>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Fri, Nov 22, 2013 at 1:19 AM, dave
fournier <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:davef@otter-rsch.com" target="_blank">davef@otter-rsch.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div class="im">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?<br>
Alex<br>
<br>
</div>
That seems highly unlikely in the sense that the mingw
compiler would be different<br>
from any other compiler in this manner. Do you have an
example?
<div class="HOEnZb">
<div class="h5"><br>
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</blockquote>
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