library(RTMB)
dat <- read.table("bh.dat", header=TRUE)
par <- list(loga=0, logb=0, logsigma=0)

nll<-function(par){
  getAll(par, dat)
  sigma <- exp(logsigma)
  pred <- loga+log(ssb)-log(1+exp(logb)*ssb)
  nll <- -sum(dnorm(logR,pred,sigma,TRUE))
  return(nll)
}

obj <- MakeADFun(nll, par, silent=TRUE)
opt <- nlminb(obj$par, obj$fn, obj$gr)
print(opt$par)

lp<-function(ls){
  pp<-par
  pp$logsigma<-ls
  objnew <- MakeADFun(nll, pp, silent=TRUE, map=list(logsigma=factor(NA)))
  nlminb(objnew$par, objnew$fn, objnew$gr)$objective
}
lp<-Vectorize(lp)
ls<-seq(-2, 0, by=0.01)

ls.pro<-TMB:::tmbprofile(obj, "logsigma")

plot(ls.pro)
points(ls, lp(ls), col="red")