hi ,

lik <- function(nO, nA, nB, nAB){

loglik <- function(par)
  {
      p=par[1]
      q=par[2]
      r <- 1 - p - q

      if (c(p,q,r) > rep(0,3) && c(p,q,r) < rep(1,3) )

        {
          -(2 * nO * log (r) + nA * log (p^2 + 2 * p * r)
            + nB * log (q^2 + 2 * q * r)
            + nAB * (log(2) +log(p) +log(q)))
       }
      else
        NA
  }

loglik

}


i want to maximize this likelihood function over the range (0,0,0) to
(1,1,1). so i tried

optim ( c(0.3,0.3), lik ( 176,182 , 60 ,17) , method = "CG")

and obtained the following :

> optim(c(0.3,0.3), fn, method="CG")
$par
[1] 0.26444187 0.09316946

$value
[1] 492.5353

$counts
function gradient
     130       19

$convergence
[1] 0

$message
NULL

Warning messages:
1: In log(q^2 + 2 * q * r) : NaNs produced
2: In log(q) : NaNs produced
3: In log(q^2 + 2 * q * r) : NaNs produced
4: In log(q) : NaNs produced


please help ...


-- 
Arindam Fadikar
M.Stat
Indian Statistical Institute.
New Delhi, India

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