-project.org
Subject: Re: [R-sig-phylo] variation in rates over time, unexpected
message when using Brownie.lite
That's a fairly small tree to be doing this with -- an old rule of thumb (I
think from Pagel) is 20 tips per parameter. Common issues are zero length
(or effectively zero length) branch
Dear all, I tried to test something similar to Jason, but relating the
change in rates to the acquisition of a trait, instead to a specific date.
For that, I used a phylogeny with ten taxa, without outgroup.
I used exactly the same script gently proposed by Liam but got the
following error
Hi Agus.
It looks like in your example the Hessian matrix of partial second
derivatives (the curvature) at the optimum is numerically singular. I'm
not sure what this means - it could be that the surface is very flat, or
alternatively that it is highly correlated.
Is the error fatal, or do
