Hi

I want to change a control parameter for an nls () as I am getting an error
message  "step factor 0.000488281 reduced below 'minFactor' of 0.000976562".
Despite all tries, it seems that the control parameter of the nls, does not
seem to get handed down to the function itself, or the error message is
using a different one.

Below system info and an example highlighting the problem.

Thanks,

Rainer


> version               _
platform       i486-pc-linux-gnu
arch           i486
os             linux-gnu
system         i486, linux-gnu
status
major          2
minor          9.2
year           2009
month          08
day            24
svn rev        49384
language       R
version.string R version 2.9.2 (2009-08-24)

> sessionInfo()
R version 2.9.2 (2009-08-24)
i486-pc-linux-gnu

locale:
LC_CTYPE=en_ZA.UTF-8;LC_NUMERIC=C;LC_TIME=en_ZA.UTF-8;LC_COLLATE=en_ZA.UTF-8;LC_MONETARY=C;LC_MESSAGES=en_ZA.UTF-8;LC_PAPER=en_ZA.UTF-8;LC_NAME=C;LC_ADDRESS=C;LC_TELEPHONE=C;LC_MEASUREMENT=en_ZA.UTF-8;LC_IDENTIFICATION=C

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] R.utils_1.2.0     R.oo_1.5.0        R.methodsS3_1.0.3 maptools_0.7-26
[5] sp_0.9-44         foreign_0.8-37

loaded via a namespace (and not attached):
[1] grid_2.9.2      lattice_0.17-25


#############################################

EXAMPLE:

dat <- data.frame(
                  x = 2006:2037,
                  y = c(143088, 140218, 137964,
                    138313, 140005, 141483, 142365,
                    144114, 145335, 146958, 148584,
                    149398, 151074, 152241, 153919,
                    155580, 157258, 158981, 160591,
                    162126, 163743, 165213, 166695,
                    168023, 169522, 170746, 172057,
                    173287, 173977, 175232, 176308,
                    177484)
                  )

nls( y ~ SSlogis(x, Asym, xmid, scal), data = dat, trace=TRUE)

(newMinFactor <- 1/(4*1024))
nls( y ~ SSlogis(x, Asym, xmid, scal), data = dat,
control=nls.control(minFactor=newMinFactor), trace=TRUE)
nls( y ~ SSlogis(x, Asym, xmid, scal), data = dat,
control=c(minFactor=newMinFactor), trace=TRUE)


(newMinFactor <- 4/1024)
nls( y ~ SSlogis(x, Asym, xmid, scal), data = dat,
control=nls.control(minFactor=newMinFactor), trace=TRUE)
nls( y ~ SSlogis(x, Asym, xmid, scal), data = dat,
control=c(minFactor=newMinFactor), trace=TRUE)



-- 
Rainer M. Krug, PhD (Conservation Ecology, SUN), MSc (Conservation Biology,
UCT), Dipl. Phys. (Germany)

Centre of Excellence for Invasion Biology
Natural Sciences Building
Office Suite 2039
Stellenbosch University
Main Campus, Merriman Avenue
Stellenbosch
South Africa

Cell:           +27 - (0)83 9479 042
Fax:            +27 - (0)86 516 2782
Fax:            +49 - (0)721 151 334 888
email:          Rainer@krugs.de

Skype:          RMkrug
Google:         R.M.Krug@gmail.com

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