R/sigma2sample.R

In YiyiLiu1/bdChemo: Cell birth and death rates estimation

sigma2sample <-
function(ss,xt,km,kv,sigma20,ll0,ls,bk,mubk){
sigma21 = rnorm(1,sigma20,ss)
if (sigma21<0){
return(list(sigma2=sigma20,ll=ll0,update=0))
} else{
ll1 = normappll(xt,km,kv,sigma21,bk,mubk)
prob = (ll1-ll0 + log(sigma20) - log(sigma21))
if ( !is.nan(prob) & log(runif(1))<prob ){
return(list(sigma2=sigma21,ll=ll1,update=1))
} else{
return(list(sigma2=sigma20,ll=ll0,update=0))
}
}
}