nls: singular convergeance
On 13/10/11 18:02, Redding, Matthew wrote:
Dear R-experts, I have 28 data points that I would like to fit with a non linear broken-stick -- with three fitted parameters. When I view trace -- and use the final values as lines on the graph of data -- it looks pretty good. Q1. Why am I getting singular convergeance? Q2. Can you suggest another approach that may prove more satisfying?
<SNIP>
Have you thought of using the "segmented" package instead
of rolling your own with nls?
cheers,
Rolf Turner