r - 您可以在 R simmer 事件模拟中检查到达属性吗？

Question

我是 R 新手，对离散事件模拟非常陌生。r.simmer 似乎是一个非常好的包，因此尝试使用它来模拟医院床位入院策略，对我来说，轨迹分支选项能够检查资源状态和到达的任意属性似乎很自然，例如

library(simmer)

daypatient<-trajectory() %>%
 log_("sent home") %>%
 timeout(300) %>%
 seize("admin",1) %>%
 release("admin",1) %>%
 seize("bed",1)

patient <-trajectory() %>%
 log_("start pat") %>%
 branch(
    function() rnorm(1)>0.5 ,
    # actually want to inspect arrival priority and queues to decide which trajectory path to follow
    continue= TRUE,
    daypatient
  ) %>%
 seize("bed",1) %>%
 seize("theatre",1) %>%
 timeout(rnorm(1,5)) %>%
 release("theatre",1) %>%
 timeout(50) %>%
 release("bed",1)
# some patients need treatment pdq...
serious<-data.frame(time=rexp(10,1),priority=2)
# ... other less so
wounded<-data.frame(time=rexp(10,1),priority=1)

hos <- simmer() %>%
 add_resource("bed",2) %>%
 add_resource("admin",3) %>%
 add_resource("theatre",1) %>%
 add_dataframe("serious",
               patient,
               serious) %>%
 add_dataframe("wounded",
               patient,
               wounded)

hos %>% run(until = 500)

有什么办法可以做到这一点，还是我从根本上误解了 r.simmer/DES 框架？

Answer 1

用毅力找到了

...
  branch(
    function () {
      crit<-get_attribute(hos,"crit")
      avail<-get_queue_count(hos,"bed")
      if( sendhomeoption && avail==0 && crit == 1 ){
        return (TRUE)
      } else {
        return(FALSE)
      }
     } ,
     # actually want to inspect arrival and queues 
     continue= c(TRUE,FALSE),
     daypatient,
     immediate
   ) %>%
...