R/optim_rand.R

In HaoLi111/rMathModeling: R Functional Programming Solution for Mathematical Modeling 4 Ed

#optim_rand
optim_rand = function(f,init1,init2 = NULL,
                      n = 100){
  if(is.null(init2)){
    init2 = as.numeric(init1[2])
    init1 = as.numeric(init1[1])
  }
  base = runif(n,min = init1,max=init2)
  re = f(base)
  list(opt = min(re,na.rm = T),
       dep = base[which.min(re)])
}
parOptim_rand = function(f,init1,init2 = NULL,n=1e5,divide = 4){
  if(is.null(init2)){
    init2 = as.numeric(init1[2])
    init1 = as.numeric(init1[1])
  }
  re=foreach(i = 1:divide,.combine = rbind) %dopar% {
    base = runif(n,min = init1,max=init2)
    r = ifelse(isTRUE(x(base)),
                f(base),NA)
    c(opt = min(r,na.rm = T),
         dep = base[which.min(r)])
  }
  list(opt = min(re[,2],na.rm = T),
       dep = re[which.min(re[,2]),1])
}