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考虑下面指定的系统和路由算法： 系统图像。让我们首先定义一些在模拟中有用的属性：

library(simmer)
library(parallel)
library(simmer.plot)
#############################
d<- 2
#############################
set.seed(1337)
sim<-simmer()

#let's say the system has 1000 servers/respective queues
queues<- vector(length=1000)
for (i in 1:1000) {
  queues[i]<- paste0("q_",i)
}


queueing_system <- trajectory() %>%
  set_attribute("X", function() rexp(1,100)) %>%
#"e_i", i in {1,2} will be the number of the queue sampled
  set_attribute(paste0("e", 1:d), function() sample(1000,2)) %>% 

#d_i will be the size of these respective queues

  set_attribute("d1", function() get_server_count(sim,queues[get_attribute(sim,"e1")]))%>%
  set_attribute("d2", function() get_server_count(sim,queues[get_attribute(sim,"e2")]))

现在，让我们定义路由算法和之后的轨迹。

我们可以尝试完全在克隆函数中表达路由算法，如下所示：

number_of_clones <- function(a,b)
{
if(function() a+b==0){2}else{1}}

routing_logic <- function(a,b,c,d)
{
  if((a>=1 & b=0)|(a=0 & b>=1))
  {
    trajectory()%>%
    select(function() queues[get_attribute(sim,c(c,d)[which(c(a,b)==0)])])%>%
    seize_selected()%>%
      timeout(function() get_attribute(sim, "X")*(rpois(1, 10)+1)) 

  }
  else if (a>=1 & b>=1){
    trajectory()%>%
    select(function() queues[get_attribute(sim,sample(c(c,d)),1)])%>%
    seize_selected()%>%
    timeout(function() get_attribute(sim, "X")*(rpois(1, 10)+1))

  }
  else if (a+b==0){
    n <- trajectory()%>%
      select(function() queues[get_attribute(sim,c)])%>%
      seize_selected()%>%
      timeout(function() get_attribute(sim, "X")*(rpois(1, 10)+1))
    m <- trajectory()%>%
      select(function() queues[get_attribute(sim,d)])%>%
      seize_selected()%>%
      timeout(function() get_attribute(sim, "X")*(rpois(1, 10)+1))
    list(n,m)
  }

}

#trajectory is then expressed as
queueing_system %>%
  clone(number_of_clones(get_attribute(sim,"d1"),get_attribute(sim,"d2")),routing_logic(get_attribute(sim,"d1"),get_attribute(sim,"d2"),"e1","e2"))%>%
synchronize(FALSE)%>%
  release_selected()

我们现在收到以下问题：

> queueing_system %>%
+   clone(number_of_clones(get_attribute(sim,"d1"),get_attribute(sim,"d2")),routing_logic(get_attribute(sim,"d1"),get_attribute(sim,"d2"),"e1","e2"))%>%
+ synchronize(FALSE)%>%
+   release_selected()
Error: there is no arrival running

我认为这与在我的“if”和“else if”语句的条件下调用函数有关，尽管我不确定我到底做错了什么。

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1 回答 1

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该函数get_attribute不能直接调用。相反，它必须放在模拟期间调用的函数中。

于 2019-06-07T21:42:05.050 回答