I have following code:
loglikelihood <- function(alpha,beta= 0.1){
    loglh<-0
    d<-0
    p<-0
    k<-NULL
    data<-read.table("epidemic.txt",header = TRUE)
    attach(data, warn.conflicts = F)
    k <-which(inftime==1)
    d <- (sqrt((x-x[k])^2+(y-y[k])^2))^(-beta)
    p<-1 - exp(-alpha*d)
    for(i in 1:100){
        if(i!=k){
            if(inftime[i]==0){
                loglh<-loglh +log(1-p[i])
            }
            if(inftime[i]==2){
                loglh<-loglh + log(p[i])
            }
        }
    }
    return(loglh)
}
Here p[i] <- 1 - exp(-alpha*d^(-beta))
so,  log(p[i]) produces NaNs when exp(-alpha*d^(-beta)) is greater than 1.
How can I remove it.After generating the out put we can omit it, but the
problem is different.

On Tue, Nov 29, 2011 at 5:22 PM, Gyanendra Pokharel <
gyanendra.pokharel@gmail.com> wrote:

> No, that,s not a problem Michael,
> I have following code:
> loglikelihood <- function(alpha,beta= 0.1){
>     loglh<-0
>     d<-0
>     p<-0
>     k<-NULL
>     data<-read.table("epidemic.txt",header = TRUE)
>     attach(data, warn.conflicts = F)
>     k <-which(inftime==1)
>     d <- (sqrt((x-x[k])^2+(y-y[k])^2))^(-beta)
>     p<-1 - exp(-alpha*d)
>     for(i in 1:100){
>         if(i!=k){
>             if(inftime[i]==0){
>                 loglh<-loglh +log(1-p[i])
>             }
>             if(inftime[i]==2){
>                 loglh<-loglh + log(p[i])
>             }
>         }
>     }
>     return(loglh)
> }
> Here p[i] <- 1 - exp(-alpha*d^(-beta))
> so,  log(p[i]) produces NaNs when exp(-alpha*d^(-beta)) is greater than 1.
> How can I remove it.After generating the out put we can omit it, but the
> problem is different.
>
>
>
> On Tue, Nov 29, 2011 at 5:07 PM, R. Michael Weylandt <
> michael.weylandt@gmail.com> wrote:
>
>> Do you mean remove the NaNs? Try na.omit() or complete.cases() or many
>> other options.
>>
>> If you mean you want the complex log, try
>>
>> log(as.complex(1-exp(-a)))
>>
>> Michael
>>
>> On Tue, Nov 29, 2011 at 5:02 PM, Gyanendra Pokharel
>> <gyanendra.pokharel@gmail.com> wrote:
>> > Hi all I have a function of log defined by y = log(1- exp(-a)), when
>> > exp(-a) is greater, 1, it produce NaN. How can I remove this in R?
>> >
>> >        [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
>> > 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<http://www.r-project.org/posting-guide.html>
>> > and provide commented, minimal, self-contained, reproducible code.
>> >
>>
>
>

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