simmer 4.2.1

New features:

• New handle_unfinished() activity sets a drop-out trajectory for unfinished
  arrivals, i.e., those dropped from a resource (due to preemption, resource
  shrinkage or a rejected seize) or those that leave a trajectory (#178
  addressing #177).
• New release_all() and release_selected_all() activities automatically
  retrieve the amount of resources seized and release it (#180 addressing #25).
• New get_seized() and get_seized_selected() getters allow an arrival to
  retrieve the amount of resources seized (#180 addressing #179).
• New stop_if() activity sets a conditional breakpoint (#181 addressing #100).

Minor changes and fixes:

• Fix performance issues in data sources (#176).
• Update CITATION.
• Fix monitored activity for preempted arrivals (as part of #178).
• Fix seizes/releases with a null amount (as part of #180).
• Rename internal status codes (as part of #181).
• Provide more context on error or warning (as part of #181).
• Extend the Queueing Systems vignette with a section about state-dependent
  service rates.
• Fix performance issues in getters (#183).
• 4.2.0 (untagged) -> 4.2.1: Fix memtest notes on CRAN (e741686).

simmer 4.1.0

New features:

• New getter get_selected() retrieves names of selected resources via the select() activity (#172 addressing #171).
• Source and resource getters have been vectorised to retrieve parameters from multiple entities (as part of #172).
• Simplify C++ Simulator interface for adding processes and resources (#162). The responsibility of building the objects has been moved to the caller.
• New add_global() method to attach global attributes to a simulation environment (#174 addressing #158).

Minor changes and fixes:

• Remove 3.8.0 and 4.0.1 deprecations (#170 addressing #165).
• Fix get_global() to work outside trajectories (#170 addressing #165).
• Fix rollback() with an infinite amount (#173).
• Fix and improve schedules and managers (as part of #174).
• Fix reset() to avoid overwriting the simulation environment (#175).

simmer 4.0.1

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.

simmer 4.0.0

• The simmer license has been changed to GPL >= 2.

New features:

• The C++ core has been refactorised into a header-only library under inst/include (#147 closing #145). Therefore, from now on it is possible to extend the C++ API from another package by listing simmer under the LinkingTo field in the DESCRIPTION file.
• New generic monitor constructor enables the development of new monitoring backends in other packages (179f656, as part of #147).
• New simulation-scoped logging levels. The log_ activity has a new argument level which determines whether the message is printed depending on a global log_level defined in the simmer constructor (#152).
• set_attribute and set_global gain a new argument to automatically initialise new attributes (#157). Useful to update counters and indexes in a single line, without initialisation boilerplate.

Minor changes and fixes:

• Enhanced exception handling, with more informative error messages (#148).
• Refactorisation of the printing methods and associated code (#149).
• Allow empty trajectories in sources and activities with sub-trajectories (#151 closing #150).
• Enable RCPP_PROTECTED_EVAL (Rcpp >= 0.12.17.3), which provides fast evaluation of R expressions by leveraging the new stack unwinding protection API (R >= 3.5.0).
• Replace backspace usage in vector's ostream method (2b2f43e).
• Fix namespace clashes with rlang and purrr (#154).

simmer 3.8.0

New features:

• New data source add_dataframe enables the attachment of precomputed data, in the form of a data frame, to a trajectory. It can be used instead of (or along with) add_generator. The most notable advantage over the latter is that add_dataframe is able to automatically set attributes and prioritisation values per arrival based on columns of the provided data frame (#140 closing #123).
• New set_source activity deprecates set_distribution(). It works both for generators and data sources (275a09c, as part of #140).
• New monitoring interface allows for disk offloading. The simmer() constructor gains a new argument mon to provide different types of monitors. By default, monitoring is performed in-memory, as usual. Additionally, monitoring can be offloaded to disk through monitor_delim and monitor_csv, which produce flat delimited files. But more importantly, the C++ interface has been refactorised to enable the development of new monitoring backends (#146 closing #119).

Minor changes and fixes:

• Some documentation improvements (1e14ed7, 194ed05).
• New default until=Inf for the run method (3e6aae9, as part of #140).
• branch and clone now accept lists of trajectories, in the same way as join, so that there is no need to use do.call (#142).
• The argument continue (present in seize and branch) is recycled if only one value is provided but several sub-trajectories are defined (#143).
• Fix process reset: sources are reset in strict order of creation (e7d909b).
• Fix infinite timeouts (#144).

simmer 3.7.0

New features:

• New timeout_from_attribute() activity makes it easier to set a timeout based on an attribute (#129).
• The activities set_attribute(), set_prioritization(), set_capacity() and set_queue_size() get a new argument mod which, if set to "+" or "*", modifies the corresponding value instead of substituting it. This makes it easier to increment, decrement or scale one of these values (#130).
• New *_selected() versions for the already available resource getters: get_capacity(), get_queue seize(), get_server_count() and get_queue_count() (#134).

Minor changes and fixes:

• Broadcast signals with higher priority to prevent an arrival to catch its own signal with a trap() after a send() (#135).
• Generate new arrivals with minimum priority to avoid wrong interactions with simultaneous activities (#136).
• Remove v3.6.x deprecations: the old attribute retrieval system (see notes for v3.6.3), as well as methods create_trajectory() and onestep() (#117).
• Remove get_mon_resources()'s data argument. It was there for historical reasons and probably nobody was using it (851d34b).
• New vignette, "simmer: Discrete-Event Simuation for R", paper accepted for publication in the Journal of Statistical Software. Remove "Terminology" vignette (#127).
• New vignette, "Design and Analysis of 5G Scenarios", supplementary materials for a paper accepted for publication in the IEEE Communications Magazine (#137).

simmer 3.6.5

New features:

• set_attribute() (and set_global() by extension) can set multiple attributes at once by providing vectors of keys and values (or functions returning such keys and/or values). get_attribute() (and get_global() by extension) can retrieve multiple keys (#122).
• New stepn() method deprecates onestep() (e452975).

Minor changes and fixes:

• Restore ostream after formatting (9ff11f8).
• Fix arrival cloning to copy attributes over to the clone (#118).
• Fix self-induced preemption through set_capacity() (#125).
• Update "Queueing Systems" vignette (a0409a0, 8f03f4f).
• Update "Advanced Trajectory Usage" vignette (4501927).
• Fix print methods to return the object invisibly (#128).
• New "Dining Philosophers Problem" vignette (ff6137e).

simmer 3.6.4

Minor changes and fixes:

• Fix preemption in non-saturated multi-server resources when seizing amounts > 1 (#114).
• Fix queue priority in non-saturated finite-queue resources when seizing amounts > 1 (#115).
• Fix resource seizing: avoid jumping the queue when there is room in the server but other arrivals are waiting (#116).

simmer 3.6.3

New features:

• Show simulation progress via an optional progress callback in run() (#103).
• New "The Bank Tutorial: Part II" vignette, by Duncan Garmonsway @nacnudus (#106).
• New getters for running arrivals (#109), meant to be used inside trajectories:
  • get_name() retrieves the arrival name.
  • get_attribute() retrieves an attribute by name. The old method of retrieving them by providing a function with one argument is deprecated in favour of get_attribute(), and will be removed in version 3.7.x.
  • get_prioritization() retrieves the three prioritization values (priority, preemptible, restart) of the active arrival.
• New shortcuts for global attributes (#110): set_global() and get_global(), equivalent to set_attribute(global=TRUE) and get_attribute(global=TRUE) respectively.

Minor changes and fixes:

• Some code refactoring and performance improvements (2f4b484, ffafe1e, f16912a, fb7941b, 2783cd8).
• Use Rcpp::DataFrame instead of Rcpp::List (#104).
• Improve argument parsing and error messages (#107).
• Improve internal function make_resetable() (c596f73).

simmer 3.6.2

Minor changes and fixes:

• Update "The Bank Tutorial: Part I" vignette (@nacnudus in #90).
• Fix trap()'s handler cloning and associated test (#91).
• Apply select()'s policy also when resources is a function (#92).
• Accept dynamic timeouts in batches (#93).
• Change rollback()'s default behaviour to times=Inf, i.e., infinite loop (#95).
• Stop and throw an error when timeout() returns a missing value (#96 and #97).
• Fix memory management: resetting the environment was clearing but not deallocating memory (#98, fixed in #99).
• Fix object destruction: workaround for tidyverse/magrittr#146 (#98, fixed in effcb6b).