On 9/11/2010 7:52 AM, Benoit Boulinguiez wrote:
Hi all,
Does one of you know if there is any way to combine a "nls" method in
the stat_smooth of ggplot?
Regards
According to the documentation for predict.nls, it is unable to create
standard errors for the predictions, so that has to be turned off in the
stat_smooth call. Also, the default formula isn't valid for nls and has
to be overridden, and the start values can be passed. I used
geom_smooth rather than stat_smooth, but either work.
library("ggplot2")
DF <- data.frame(x=1:20, y=rnorm(20))
ggplot(DF, aes(x=x, y=y)) +
geom_smooth(method="nls", formula=y~b*x+c, se=FALSE,
start=list(b=0,c=1)) +
geom_point()
ggplot(DF, aes(x=x, y=y)) +
geom_smooth(method="nls", formula=y~sin(b*x), se=FALSE,
start=list(b=1)) +
geom_point()
--
Brian S. Diggs, PhD
Senior Research Associate, Department of Surgery
Oregon Health & Science University
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