On Wed, Mar 23, 2011 at 10:24 PM, Emmanuel Paradis
<emmanuel.para...@ird.fr> wrote:
> Hi Nick,
>
> With method = "pic", the CIs are computed using the expected variances under
> the model, so they depend only on the tree. I've added a paragraph in the
> man page to explain this.
>
> Cheers,
>
> Emmanuel


Obviously, though, if one set of tip data ranges from 100-1000, and
another set of tip data ranges from 0.001-1, and both are mapped on
the same tree, the variances & confidence intervals will be different
at the estimated internal nodes for each trait.  But I was getting
identical confidence intervals across ~20 traits of widely different
magnitudes -- and then when I rescaled the trait data, the problem
went away, and each trait had different-sized CIs like you would
expect.  It was as if there some bizarre bug where there was a memory
error or some such and the same CI values were getting copied from one
trait to the next in some situations.

It's probably pointless to discuss, though, unless someone else can
replicate the problem I saw with the code I posted.  If the problem
disappears on other computers, then it's a local problem.  R.app
sometimes throws messages about memory errors and the like for no
apparent reason (not specifically associated with this, though), so it
might not even be an APE issue.

Cheers!
Nick



>
> Nick Matzke wrote on 22/03/2011 12:30:
>>
>> Hi all,
>>
>> This isn't crucial to my work at the moment since I am not using the PIC
>> option of ace to do ancestral character estimation.  But while trying it out
>> I noticed a very weird result that I can't explain...basically when I run
>> ace on my raw trait values, I get the same sized confidence interval (97.5%
>> CI minus 2.5% confidence interval) for all of my (drastically different)
>> traits.
>
>

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