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simmer 4.0.1

Iñaki Úcar

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The 4.0.1 release of simmer, the Discrete-Event Simulator for R, is on CRAN since a couple of weeks ago. There are few changes, notably new getters (get_sources(), get_resources(), get_trajectory()) for simmer environments and some improvements in resource selection policies (see details in help(select)).

A new convenience function, when_activated, makes it easier to generate arrivals on demand, triggered from trajectories. Let us consider, for instance, a simple restocking pattern:

library(simmer)

restock <- trajectory() %>%
  log_("restock")

serve <- trajectory() %>%
  log_("serve") %>%
  activate("Restock")

env <- simmer() %>%
  add_generator("Customer", serve, at(1, 2, 3)) %>%
  add_generator("Restock", restock, when_activated()) %>%
  run()
## 1: Customer0: serve
## 1: Restock0: restock
## 2: Customer1: serve
## 2: Restock1: restock
## 3: Customer2: serve
## 3: Restock2: restock

Finally, this release leverages the new fast evaluation framework offered by Rcpp (>= 0.12.18) by default, and includes some minor improvements and bug fixes.

New features:

  • New getters (#159):
    • get_sources() and get_resources() retrieve a character vector of source/resource names defined in a simulation environment.
    • get_trajectory() retrieves a trajectory to which a given source is attached.
  • New resource selection policies: shortest-queue-available, round-robin-available, random-available (#156). These are the same as the existing non-available ones, but they exclude unavailable resources (capacity set to zero). Thus, if all resources are unavailable, an error is raised.

Minor changes and fixes:

  • Rename -DRCPP_PROTECTED_EVAL (Rcpp >= 0.12.17.4) as -DRCPP_USE_UNWIND_PROTECT (6d27671).
  • Keep compilation quieter with -DBOOST_NO_AUTO_PTR (70328b6).
  • Improve log_ print (7c2e3b1).
  • Add when_activated() convenience function to easily generate arrivals on demand from trajectories (#161 closing #160).
  • Enhance schedule printing (9c66285).
  • Fix generator-manager name clashing (#163).
  • Deprecate set_attribute(global=TRUE), get_attribute(global=TRUE) and timeout_from_attribute(global=TRUE) (#164), the *_global versions should be used instead.
Article originally published in Enchufa2.es: simmer 4.0.1.

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