[R] how to solve the step halving factor problems in gnls and nls

Dieter Menne dieter.menne at menne-biomed.de
Tue Jul 19 08:42:55 CEST 2005

Yimeng Lu <yl2058 <at> columbia.edu> writes:

> Could you give me some advice in 
> solving the problem of such error message from gnls and nls?
> ## begin error message
> "Problem in gnls(y1 ~ glogit4(b, c, m, t, x), data.frame(x..: Step halving 
> factor reduced below minimum in NLS step "

Try to set nlsTol in the optional control parameter (gnlsControl) to a larger 
value, e.g. 0.1 instead of default 0.001, but be sure to check your results 
make sense. If this should help, you can try intermediate values.

Dieter Menne

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