R Under development (unstable) (2013-08-18 r63609) -- "Unsuffered Consequences"
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> library(bbmle)
Loading required package: stats4
> old_opt <- options(digits=3)
> require(optimx)
Loading required package: optimx
Loading required package: numDeriv
> x <- 0:10
> y <- c(26, 17, 13, 12, 20, 5, 9, 8, 5, 4, 8)
> d <- data.frame(x,y)
> 
> ## breaks, don't try this
> ## optimx(fn=Lfn,par=c(15,6),method="Rvmmin")
> 
> suppressWarnings(m1 <- mle2(minuslogl=y~dpois(lambda=ymax/(1+x/xhalf)),
+      start=list(ymax=15,xhalf=6),data=d,
+      optimizer="optimx",
+            method=c("BFGS","Nelder-Mead","CG")))
> 
> ## FIXME!! fails (although not with an error, because
> ##  errors are caught by profiling) due to npar now
> ## being restricted to >1 in optimx 2012.05.24 ...
> 
> suppressWarnings(head(as.data.frame(profile(m1))))
       param      z par.vals.ymax par.vals.xhalf focal
ymax.1  ymax -3.377          14.0           9.99  14.0
ymax.2  ymax -2.341          16.7           6.54  16.7
ymax.3  ymax -1.458          19.5           4.79  19.5
ymax.4  ymax -0.687          22.2           3.75  22.2
ymax.5  ymax  0.000          25.0           3.06  25.0
ymax.6  ymax  0.620          27.7           2.57  27.7
> detach("package:optimx")
> options(old_opt)
> 
> proc.time()
   user  system elapsed 
  7.848   4.400  12.412