Dear all,
I noticed the following under R 1.8.1 (when nls was still a separate
package) but the same problem occurs under R 1.9.0 (where most (all?)
of nls is now in the stats package):
> data(Puromycin)
> fm <- nls(rate~SSmicmen(conc,b0,b1), Puromycin, subset = state=="treated")
> coef(summary(fm))
NULL
The problem seems to be that summary.nls uses the name "parameters"
instead of the name "coefficients" for the matrix with the estimates,
standard errors, t values and p values:
> summary(fm)$parameters
Estimate Std. Error t value Pr(>|t|)
b0 212.68370728 6.947153198 30.614512 3.241160e-11
b1 0.06412123 0.008280944 7.743227 1.565136e-05
Thus, coef.default fails on an object of class "summary.nls".
Possible fixes:
1) Rename that part of the summary.nls structure from parameters to
coefficients (not sure if that breaks something else); or
2) Write a coef.summary.nls method that returns the structure
parameter from a summary.nls object passed to it.
Cheers,
Berwin
--please do not edit the information below--
Version:
platform = i686-pc-linux-gnu
arch = i686
os = linux-gnu
system = i686, linux-gnu
status =
major = 1
minor = 9.0
year = 2004
month = 04
day = 12
language = R
Search Path:
.GlobalEnv, package:methods, package:stats, package:graphics, package:utils,
Autoloads, package:base
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