OK. Two things are going wrong.
(1) There is an error in your code. You are passing the new.coef
argument to density() and not to rmh(). The function density() has no
such argument, but has a "..." argument, so "new.coef" simply gets ignored.
You should use:
plot(density(rmh(mod,new.coef=c(1,200))))
(2) However, even when the correct call is given you still wind up with
identical densities!!!
Hmmmmm. I think this may be a bug; I'll will check with the other
authors of spatstat and report back.
cheers,
Rolf Turner
On 16/09/14 16:30, Sebastian Schutte wrote:
Thanks so much for your comments. Sorry for not having sent a running
example from the start. Here it is:
library (spatstat)
#Load example data
data(demopat)
#Generate a random point pattern within the polygon
set.seed(12345)
pdat <- rpoint(200,win=demopat$window)
#Generate a distmap, which will serve as covariate information
im.cdat <- as.im(distmap(pdat))
#Now the random seed is fixed and a new set of random points is
generated for the example
set.seed(11111)
pdat <- rpoint(200,win=demopat$window)
#Fitting a model to the data
mod <- ppm (pdat ~ im.cdat)
#Now a point pattern is simulated via rmh from the fitted model an
visualized as a density surface
set.seed(22222)
plot(density(rmh(mod)))
#And here is the problem: When I repeat the exercise with different
coefs, the very same patter come out. "new.coef" has no effect.
set.seed(22222)
plot(density(rmh(mod),new.coef=c(1,200)))
What am I missing?
--
Rolf Turner
Technical Editor ANZJS
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
