简单马尔可夫链算法

Question

以下代码是一个用R编写的简单马尔可夫链算法，其任务是模拟2个城镇之间租赁汽车的运动，因为客户有权在任何方便他们的城镇归还他们的汽车。这两个城镇拥有最初的租车数量，经过多次迭代，我想知道每个（城镇）的汽车最终可用性。它被提供了概率的转换矩阵（p1＆amp; p2）和完整的代码。我的问题是我无法找到代码中的缺陷，因为R没有给出任何结果。我将不胜感激任何帮助。

p1 <- c(0.6,0.4)            # probabilities of Athens facilities (1st % means: stays) 
p2 <- c(0.7,0.3)            #probabilities of Chania facilities (1st % means: stays in town)
Athens.start <- 200     #number of cars in Athens at the start of the period
Chania.start <- 200     #number of cars in Chania at the start of the period
nsims <- 15
Athens <- rep(0,nsims+1)
Chania <- rep(0,nsims+1)

#Function for deciding whether to move or not a car from its initial facility
move <- function(p1,p2,Athens,Chania,i ) {
    repeat {
       #position1 is related with 1st location (Athens)
       position1 <- sample(x=c(1,2),size=1,prob=p1)
       if (position1==1) {
          Athens[i]=Athens[i]+1
          Chania[i]=Chania[i]-1
       } else {
          Athens[i]=Athens[i]-1
          Chania[i]=Chania[i]+1
       }
       #position2 is related with 2nd location (Chania)
       position2<-sample(x=c(1,2),size=1,prob=p2)
       if (position2==1) {
          Chania[i]=Chania[i]+1
          Athens[i]=Athens[i]-1
       } else {
          Chania[i]=Chania[i]-1
          Athens[i]=Athens[i]+1}
       }
       return(Athens[i])
       return(Chania[i]) 
       break
     }
     #Basic Function for simulating the movement of cars between facilities 
     cars.sims<-function(Athens.start,Chania.start,nsim) {
        Athens<-vector(length=nsim+1)
        Chania<-vector(length=nsim+1)
        Athens[1]<-Athens.start
        Chania[1]<-Chania.start
        for (i in 1:nsim) {
           Athens[i+1]<-move(p1,p2,Athens,Chania)
           Chania[i+1]<-move(p1,p2,Athens,Chania)
         }
        Towns<-rbind(Athens,Chania)
        return(Towns)
      }