Hi r-users,
 
I hope somebody can help me to understand the error message.  Here is my code;

## Newton iteration
newton_gam <- function(z)
{ n   <- length(z)
  r   <- runif(n)
  tol <- 1E-6
  cdf <- vector(length=n, mode="numeric")
  fprime <- vector(length=n, mode="numeric")
  f   <- vector(length=n, mode="numeric")
 
  for (i in 1:1000)
  { cdf  <- integrate(fprime, lower = 0, upper = z)$value
    f    <- cdf - r
    # Newton method
    z    <- z - f/fprime
    
    if (any(f < tol)) break
   }
  cbind(z,cdf)
}
 
alp  <- 2.0165
bt1  <- 29.107 ; bt2 <- 41.517
x1   <- d1d4pos[,1];x1[1:10]
x2   <- d1d4pos[,2];x2[1:10]
 
> x1   <- d1d4pos[,1];x1[1:10]
 [1] 28.4 53.6  1.3 29.5 52.1 65.9 72.6 67.6 58.7 34.5
> x2   <- d1d4pos[,2];x2[1:10]
 [1]  43.5  56.2   0.3  16.6  71.1  86.3 172.8 111.8  89.9  70.2
 
z <- (x1/bt1)+(x2/bt2); z
 
newton_gam(min(z))
newton_gam(max(z))
 
Error in -`*tmp*` : invalid argument to unary operator
> newton_gam(min(z))
       z          cdf
[1,] Inf 1.141004e-05
> newton_gam(max(z))
Error in integrate(fprime, lower = 0, upper = z) : 
  non-finite function value
 
> z[100]
[1] 7.544834
> newton_gam(z[100])
Error in integrate(fprime, lower = 0, upper = z) : 
  non-finite function value
 
Thank you.




      
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