在 R 中绘制对数似然 function

Question

Hi I have received an error of x and y length differ in my code. datasim is a simulated sample of size 1000. Please help me with this.

x <- datasim
loglik <- function(theta){
  k<- theta[1]
  lambda<- theta[2]
  out <- sum(dweibull(x,shape = k, scale=lambda, log = TRUE) )
  return(out)
}

theta<- c(0.5,1.5)
plot(theta, loglik(theta), type="l", lwd=3, main="logliklihood_Weibull, n=1000")

Answer 1

You can use a package since it's weibull you are fitting:

library(fitdistrplus)
x = rweibull(1000,20,10)
fit <- fitdist(x, "weibull")
llplot(fitg, expand=5)

Or using your loglik function:

library(lattice)

da = expand.grid(k=seq(8,22,length.out=50),
lambda = seq(9,12,length.out=50))
da$LL = apply(da,1,loglik)

wireframe(LL ~ k * lambda, data = da,
scales = list(arrows = FALSE),drape = TRUE, colorkey = TRUE)