[R] Problem in while loop

[R. Michael Weylandt]

If you run

out<- epiann(f = function(a,b) log(dnorm(a)*dnorm(b))), N = 10)

It takes less than 0.5 seconds so there's no problem I can see:
perhaps you want to look elsewhere to get better speed (like Rcpp or
general vectorization), or maybe your loglikihood is not what's
desired, but there's no problem with the loop.

Michael

On Mon, Dec 5, 2011 at 5:29 PM, Gyanendra Pokharel
<gyanendra.pokharel at gmail.com> wrote:
> Yes, I checked the acceptprob, it is very high but in my view, the while
> loop is not stopping, so there is some thing wrong in the use of while loop.
> When I removed the while loop, it returned some thing but not the result
> what I want. When i run the while loop separately, it never stops.
>
>
>
> On Mon, Dec 5, 2011 at 5:18 PM, R. Michael Weylandt
> <michael.weylandt at gmail.com> wrote:
>>
>> Your code is not reproducible nor minimal, but why don't you put a
>> command print(acceptprob) in and see if you are getting reasonable
>> values. If these values are extremely low it shouldn't surprise you
>> that your loop takes a long time to run.
>>
>> More generally, read up on the use of print() and browser() as debugging
>> tools.
>>
>> Michael
>>
>> On Mon, Dec 5, 2011 at 3:47 PM, Gyanendra Pokharel
>> <gyanendra.pokharel at gmail.com> wrote:
>> > I forgot to upload the R-code in last email, so heare is one
>> >
>> > epiann <- function(T0 = 1, N=1000, ainit=1, binit=1,rho = 0.99, amean =
>> > 3,
>> > bmean=1.6, avar =.1, bvar=.1, f){
>> >
>> >        moving <- 1
>> >        count <- 0
>> >        Temp <- T0
>> >        aout <- ainit
>> >        bout <- binit
>> >        while(moving > 0){
>> >                moving <- 0
>> >                for (i in 1:N) {
>> >                aprop <- rnorm (1,amean, avar)
>> >                bprop <- rnorm (1,bmean, bvar)
>> >                if (aprop > 0 & bprop > 0){
>> >                acceptprob <- min(1,exp((f(aout, bout) -
>> > f(aprop,bprop))/Temp))
>> >                u <- runif(1)
>> >                if(u<acceptprob){
>> >                    moving <- moving +1
>> >                    aout <- aprop
>> >                    bout <- bprop
>> >                    }
>> >                    else{aprob <- aout
>> >                        bprob <- bout}
>> >                }
>> >            }
>> >        Temp <- Temp*rho
>> >            count <- count +1
>> >
>> >    }
>> >    fmin <- f(aout,bout)
>> >    return(c(aout, bout,fmin, count) )
>> >
>> > }
>> > out<- epiann(f = loglikelihood)
>> >
>> > On Mon, Dec 5, 2011 at 3:46 PM, Gyanendra Pokharel <
>> > gyanendra.pokharel at gmail.com> wrote:
>> >
>> >> Hi all,
>> >> I have the following code,
>> >> When I run the code, it never terminate this is because of the while
>> >> loop
>> >> i am using. In general, if you need a loop for which you don't know in
>> >> advance how many iterations there will be, you can use the `while'
>> >> statement so here too i don't know the number how many iterations are
>> >> there. So Can some one suggest me whats going on?
>> >> I am using the Metropolis simulated annealing algorithm
>> >> Best
>> >>
>> >
>> >        [[alternative HTML version deleted]]
>> >
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>
>