Hi all,

I realize that I wasn't very clear in what I am looking for.  There is a
function LTRE in the popbio() package, however it basically performs LTRE on
columns (stage classes).  What I would like to do is to decompose matrix
elements of transition matrices into their vital rates.

The equations are included in Caswell, H. 1996. Analysis of life table
response experiments II. Alternative parameterizations for size- and
stage-structured models. Ecological Modelling 88: 73-82, specifically
equations 16:22.  However, I am unable to code the mathematical formulas
into R, and am wondering if anyone has done this or has an example matrix
that has been decomposed in this way and if so, would they be willing to
share the code.  Most transition matrices are going to have their own
qualities, so I think LTRE for decomposed vital rates will most likely have
to be customized for each situation, but at the present time I don't even
know how to get started on it.

Thanks for any help,

Wade

On Fri, Jun 24, 2011 at 2:55 PM, Wade Wall <wade.wall@gmail.com> wrote:

> Hi all,
>
> I am trying to perform a life table response experiment analysis on some
> demographic data that I collected, but am having a hard time with some of
> the intimidating formulas.  Basically, I am trying to emulate H. Caswell's
> formulas from '89 and '96 Ecological Modelling papers on LTREs, specifically
> how Brault and Caswell analyzed killer whale data in their 1993 paper.
> However, I am unable to translate the math formulas into R or to even know
> if I have done it right.  My question is, other than what is in popbio(),
> the LTRE function, has anyone seen any code or would be willing to share
> some code to get me started. I think that if I could see the R code from an
> example, I would be able to reverse engineer.
>
> Any help would be appreciated,
>
> Wade
>

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