CHANGELOG.md

v4.2

New features and fixes

• Self-contained features of Agents.jl will from now own exist in their own submodules. This will make the public API less cluttered and functionality more contained. Currently the new submodules are Schedulers, Pathfinding, OSM.
• Pathfinding using the A* algorithm is now possible! Available for GridSpace.
• Extend dataname (formerly aggname) to provide unique column names in collection dataframes when using anonymous functions
• Fixed omission which did not enable updating properties of a model when model.properties is a struct.
• New function ensemblerun! for running ensemble model simulations.
• Scheduler Schedulers.by_property (previously property_activation) now allows as input arbitrary functions besides symbols.

Deprecated

• Deprecate aggname in favor of dataname for naming of columns in collection dataframes
• Keyword replicates of run! is deprecated in favor of ensemblerun!.
• paramscan with replicates is deprecated. If you want to parameter scan and at the same time run multiple simulations at each parameter combination, simply use seed as a parameter, which tunes the model's initial random seed.
• All the scheduler names have been deprecated in favor of a Schedulers module: fastest to Schedulers.fastest, by_id to Schedulers.by_id, random_activation to Schedulers.randomly, partial_activation to Schedulers.partially, property_activation to Schedulers.by_property, by_type to Schedulers.by_type.

v4.1.2

• Plotting with Plots.jl and plotabm is deprecated in favor of InteractiveDynamics.jl, Makie.jl and abm_plot.

v4.1

• A new example: Fractal Growth, explores ContinuousSpace and interactive plotting.
• Models now supply a random number generator pool that is used in all random-related functions like random_position. Access it with model.rng and seed it with seed!(model, seed).
• Higher-order agent grouping utilities to facilitate complex interactions, see e.g. iter_agent_groups.
• Several documentation improvements targeting newcomers.

v4.0, Major new release!

This new release brings not only a lot of new features but also a lot of performance improvements and quality of life improvements. Worth seeing is also the new Comparison section of our docs, which compares Agents.jl with other existing software, showing that Agents.jl outmatches all current standards.

New features:

• GridSpace has been re-written from scratch! It now supports any dimensionality and is about a full order of magnitude faster than the previous version!
• ContinuousSpace has been re-written from scratch! It is now at least 3 times faster!
• A new, continuous OpenStreetMapSpace which lets agents traverse real world locations via planned routes based on the Open Street Map initiative.
• GraphSpace now allows to dynamically mutate the underlying graph via add_node!, rem_node!.
• Agents.jl now defines a clear API for new spaces types. To create a fundamentally different type of space you have to define the space structure and extend only 5 methods.
• GraphSpace and GridSpace are completely separated entities, reducing complexity of source code dramatically, and removing unnecessary functions like vertex2coord and coord2vertex.
• Many things have been renamed to have clearer name that indicates their meaning (see Breaking changes).
• Performance increase of finding neighbors in GraphSpace with r > 1.
• New wrapping function nearby_agents that returns an iterable of neighboring agents.
• Positions and neighbors on GridSpace can now be searched in each direction separately by accepting r as a tuple.
• Neighbors on non-periodic chebyshev spaces can also be searched per dimension over a specific range.
• New public schedule function for writing custom loops.
• Mixed models are supported in data collection methods.
• random_agent(model, condition) allows obtaining random agents that satisfy given condition.
• New walk! utility function for GridSpace and ContinuousSpaces, providing turtle-like agent movement and random walks.
• The Battle Royal example explores using categorical neighbor searching in a high dimensional GridSpace.
• An @agent macro provides a quick way of creating agent structs for any space.

Breaking changes

Most changes in this section (besides changes to default values) are deprecated and therefore are not "truly breaking".

• New ContinuousSpace now only supports Euclidean metric.
• Keyword moore of GridSpace doesn't exist anymore. Use metric instead.
• Default arguments for GridSpace are now periodic = true, metric = :chebyshev.
• Internal structure of the fundamental types like ABM, GraphSpace, etc. is now explicitly not part of the public API, and the provided functions like getindex and getproperty have to be used. This will allow performance updates in the future that may change internals but not lead to breaking changes.
• vertex2coord, coord2vertex do not exist anymore because they are unnecessary in the new design.
• API simplification and renaming:
  • space_neighbors -> nearby_ids
  • node_neighbors -> nearby_positions
  • get_node_contents -> ids_in_position
  • get_node_agents -> agents_in_position
  • pick_empty -> random_empty
  • find_empty_nodes -> empty_positions
  • has_empty_nodes -> has_empty_positions
  • nodes -> positions

Non-breaking changes

• GridSpace agents now use Dims rather than Tuple{N,Int} for their position in all examples and pre-defined models.

v3.7

• Add the ability to decide whether the agent step or the model step should be performed first using the agents_first argument.

v3.6

• Add ability to customise run! such that mutation on containers and nested structures does not affect data collection.

v3.5

• Aggregation data for agents is now possible to do conditionally.
• Example on how to integrate Agents.jl with BlackBoxOptim.jl.

v3.4

• Added interactivity examples for Schelling and Daisyworld.
• Example on how to integrate Agents.jl with DifferentialEquations.jl.
• Dropped support for Julia 1.0, will be targeting LTS for v1.6 in the future.

v3.3

• New fill_space! function for discrete spaces.
• The Daisyworld example now uses multi-agent approach (surface is agent).
• New allids function.

v3.2

• New Models submodule, that conveniently allows loading a model from the examples.

v3.1

• Extend interacting_pairs to allow interactions of disparate types when using mixed models.

v3.0

Additions

• Added ContinuousSpace as a space option. Supports Euclidean and Cityblock metrics. Several new API functions were added for continuous space.
• Universal plotting function plotabm that works for models with any kind of space.
• new function space_neighbors, which works for any space. It always and consistently returns the IDs of neighbors irrespectively of the spatial structure.
• AgentBasedModel now allows you to pass in an AbstractAgent type, or an instance of your agent.
• New convenience function allagents.
• New continuous space functions nearest_neighbor and elastic_collision!.
• New iterator interacting_pairs.
• Agents can be accessed from the model directly. model[id] is equivalent with model.agents[id] and replaces id2agent.
• If model.properties is a dictionary with key type Symbol, then the convenience syntax model.prop returns model.properties[:prop].
• Version of add_agent! now has keyword propagation as well (in case you make your types with @kwdef or Parameters.jl).
• New function nextid
• Cool new logo.
• node_neighbors now accepts a neighbor_type keyword for working with directed graphs.
• Added examples of flocking birds and bacterial growth in ContinuousSpace, daisyworld and predator-prey in GridSpace.

• Collection of model and agent data simultaneously is now possible using the mdata and adata keywords (respectively) used in conjunction with the revamped data collection scheme (see below).
• Better support for mixed-ABMs and a new by_type scheduler.

Breaking Changes

• Deprecated Space in favor of the individual spaces: Nothing, GridSpace, GraphSpace, ContinuousSpace.
• Reworked the public API of GridSpace to be simpler: position must be NTuple{Int}. As a result vertex2coord and stuff no longer exported, since they are obsolete.

• Data collection has been completely overhauled. The main function to evolve an ABM and collect data is now run!. This function serves most situations, however multiple low level functions are exposed via the API for power users. See the Data Collection section in the documentation for full details.
• AgentBasedModel checks the construction of your agent and will return errors when it is malformed (no id or pos when required, incorrect types). Warnings when possible problems may occur (immutable agents, types which are not concrete, vel not of the correct type when using ContinuousSpace).
• id2agent is deprecated in favor of getindex(model, id) == model[id].

• Function plot2D doesn't exist any more in favor of plotabm.

v2.1

• Renamed the old scheduler as_added to by_id, to reflect reality.
• Added a scheduler public API.
• Added two new schedulers: partial_activation, property_activation.
• It is now possible to step! until a boolean condition is met.

v2.0

Changelog is kept with respect to version 2.0.