The history of mosaik

Our work on mosaik started on July 15th, 2010 – at least, the initial commit happened on that day. Since then, we’ve come a long way …

3.3.3 - 2024-05-21

3.3.2 - 2024-04-12

  • [FIX] Fix versioning issue

3.3.1 - 2024-04-12

3.3.0 - 2024-01-17

3.2.0 - 2023-08-31

3.1.1 - 2023-01-11

3.1.0 - 2022-11-23

3.0.2 - 2022-06-01

  • [CHANGE] Updated mosaik-api version to 3.0.2

3.0.1 - 2022-05-02

  • [CHANGE] Set external events via highlevel function call

  • [FIX] Allow PATCH version to be included in the mosaik-api version format

3.0.0 - 2021-06-07

  • This is a major upgrade to improve the discrete-event capabilities. Simulators’ steps can now also be triggered by the output of other simulators.

  • [NEW] Native support of discrete-event simulations

  • [NEW] A global time resolution can be set for the scenario.

  • [NEW] Simulators can request steps asynchronously via set_event() to react to external events.

  • [NEW] Ability to specify output data as non-persistent (i.e. transient)

  • [CHANGE] New api 3: - Simulators have now a type (‘time-based’|’event-based’|’hybrid’). - time_resolution is passed as argument of the init function. - max_advance is passed as argument of the step function.

  • [CHANGE] Update of the documentation

2.6.1 - 2021-06-04

  • [CHANGE] Updated ReadTheDocs to support versioning

  • [CHANGE] Updated setup: mosaik-api>=2.3,<3

  • [CHANGE] Updated networkx version to 2.5

2.6.0 - 2020-05-08

  • [NEW] The print of the simulation progress is now optional and can be disabled via a flag, print_progress=False).

  • [NEW] Additional starters can now be added via external packages (the standard ones are ‘python’, ‘cmd’, and ‘connect’).

2.5.3 - 2020-04-30

  • [FIX] Constrain simpy version to <4.0.0 due to incompatibility

  • [CHANGE] Updated Odysseus tutorial

  • [CHANGE] Eliminated shifted_cache which reduces memory consumption

2.5.2 - 2019-11-01

  • [NEW] Special characters are now allowed in path names

  • [NEW] Compatible to the new versions of networkx

  • [CHANGE] python 3.6, 3.7 and 3.8 are currently supported, python 3.4 and 3.5 not anymore.

  • [FIX] Various minor internal changes

  • [FIX] Various documentation updates and fixes

2.5.1 - 2018-11-29

  • [NEW] When calling the world.start() command for a simulator, users can now set a predefined value for the posix flag (e.g. True) to prevent automatic detection of the operating system. This facilitates the creation of some co-simulation cases across OS (e.g. Windows and Linux).

2.5.0 - 2018-09-05

  • [NEW] Connection option “time_shifted” added as alternative to async_requests. This will make creating cyclic data dependencies between simulators more usable since usage of set_data with an API implementation will no longer be needed.

2.4.0 - 2017-12-06

  • [NEW] Compatible to the new versions of networkx, simpy and

  • [CHANGE] python 3.4, 3.5 and 3.6 are currently supported python 3.3 is no longer supported

  • [FIX] Various bug fixes

2.3.0 - 2016-04-26

  • [NEW] Allow passing environment vars to sup processes

  • [FIX] Fixed a bug in the version validation which raised an error when using a floating point for the version

2.2.0 - 2016-02-15

  • [NEW] API version 2.2: Added an optional “setup_done()” method.

  • [CHANGE] API version validation: The API version is no longer an integer but a “major.minor” string. The major part has to math with mosaiks major version. The minor part may be lower or equal to mosaik’s minor version.

  • [FIX] Various minor fixes and stability improvements.

  • [FIX] Various docuentation updates and fixes.

2.1 – 2014-10-24

  • [NEW] Mosaik can now perform real-time simulations. Before, this functionality needed to be implemented by simulators. Now it’s just, rt_factor=y), where rt_factor defines the simulation speed relative to the wall-clock time (issue #24).

  • [NEW] Simulators can now expose extra methods via their API that can be called from a mosaik scenario. This allows you to, e.g., store static data in a data base. These extra API methods need to be specified in the simulator’s meta data (issue #26).

  • [NEW] util.connect_many_to_one() helper function.

  • [NEW] More and better documentation:

    • Tutorial for integrating simulators, control strategies and for creating scenarios.

    • Sim API description

    • Scenario API description

    • Sim Manager documentation

    • Scheduler documentation

    • Discussion of design decisions

    • Logo, colors, CI

  • [NEW] Added util.sync_call() which eases calling proxied methods of a simulator synchronously.

  • [CHANGE] The rel attribute in the entity description returned by create() is now optional.

  • [CHANGE] Moved proxied methods from SimProxy to SimProxy.proxy in order to avoid potential name clashes with other attributes.

  • [CHANGE] Check a simulator’s models and extra API methods for potential name clashes with the built-in API methods.

  • [CHANGE] The argument execution_graph of World was renamed to debug. The execution graph now also stores the time after a simulation step (in addition to the time before the step).

  • [FIX] issue #22: The asynchronous requests get_data() and set_data() now check if the async_requests flag was set in World.connect().

  • [FIX] issue #23: finalize() is now called for in-process Python simulators.

  • [FIX] issue #27: Dramatically improved simulation performance (30 times as fast in some cases) if simulators use different step sizes (e.g. 1 minute and 1 hour) by improving some internal data structures.

2.0 – 2014-09-22

  • [NEW] Updated documentation

  • [CHANGE] Separated mosaik’s package and API version. The former stays a string with a semantic version number; the later is now a simple integer (issue #17).

  • [CHANGE] Start/stop timeout for simulators was raised from 2 to 10 seconds.

  • [CHANGE] Updated the mosaik logo. It now uses the flat colors and has some improved icon graphics.

  • [CHANGE] Renamed mosaik.simulator to mosaik.scheduler.

  • [CHANGE] Entity and the World’s entity graph now store their simulator name.

  • [FIX] issue #16: Mosaik now always prints the name of the simulator if it closes its socket.

2.0a4 – 2014-07-31

  • [NEW] The model meta data may now contain the any_inputs which, if set to True, allows any attribute to be connected to that model (useful for databases and alike).

  • [CHANGE] The dictionary of input values in the API’s step() call now also contains the source of a particular value. This is also usefull to for databases. This may break existing simulators.

  • [CHANGE] “.” is now used as separator in full entiy IDs instead of “/” (issue #19).

2.0a3 – 2014-06-26

  • [NEW] Hierarchical entities: Entities can now have a list of child entities (issue #14).

  • [NEW] The World class now has a get_data() method that allows you to get data from entities while creating a scenario.

  • [NEW] World.connect(a, b, ('X', 'X')) can now be simplified to World.connect(a, b, 'X').

  • [NEW] Attribute Entity.full_id which uniquely identifies an entity: '<sid>/<eid>'

  • [NEW] Attribute ModelFactory.meta which is the meta data dictionary of a simulator.

  • [NEW] World() now accepts a configuration dictionary which can, e.g., specify the network address for mosaik.

  • [NEW] Overview section for the docs

  • [NEW] Description of the mosaik API in the docs

  • [CHANGE] When you create entities, mosaik checks if the model parameters actually exists and raises an error if not (issue #9).

  • [CHANGE] The mosaik API’s init() function now receives the simulator ID as first argument (issue #15).

  • [CHANGE] The behavior of the get_related_entities() RPC that simulators can perform has been changed.

  • [CHANGE] Various internal improvements

  • [FIX] issue #18. Improved the error message if a Python simulator could not be imported.

  • [REMOVED] Attribute Entity.rel.

2.0a2 – 2014-05-05

  • [NEW] Preliminary documentation and installation instructions (

  • [NEW] Simulators can now set data to other simulators using the asynchronous request set_data (issue #1).

  • [NEW] There is now a start timeout for external processes (issue #11).

  • [CHANGE] Mosaik now raises an error if a simulator uses the wrong API version (issue #4).

  • [CHANGE] Mosaik prints everything to stdout instead of using the Python logging module (issue #7).

  • [FIX] issue #2. Scheduling now works properly for processes using async. requests. New keyword argument async_requests for World.connect().

  • [FIX] issue #3. Local (in-process) Simulators can now also perform async. requests to mosaik (get_progress, get_related_entities, get_data, set_data).

  • [FIX] issue #8. Cleaned up the code a bit.

  • [FIX] issue #10. Tests for the sim manager improved.

2.0a1 – 2014-03-26

  • Mosaik 2 is a complete rewrite of mosaik 1 in order to improve its maintainability and flexibility. It is still an early alpha version and neither feature complete nor bug free.

  • Removed features:

    • The mosl DSL (including Eclipse xtext and Java) are now gone. Mosaik now only uses Python.

    • Mosaik now longer has executables but is now used as a library.

    • The platform manager is gone.

    • Mosaik no longer includes a database.

    • Mosaik no longer includes a web UI.

  • Mosaik now consists of four core components with the following feature sets:

    • mosaik API

      • The API has bean cleaned up and simplified.

      • Simulators and control strategies share the same API.

      • There are only four calls from mosaik to a simulator: init, create, step and get_data.

      • Simulators / processes can make asynchronous requests to mosaik during a step: get_progress, get_related_entities, get_data.

      • ZeroMQ with JSON is replaced by plain network sockets with JSON.

    • Scenarios:

      • Pure Python is now used to describe scenarios. This offers you more flexibility to create complex scenarios.

      • Scenario creation simplified: Start a simulator to get a model factory. Use the factory to create model instances (entities). Connect entities. Run simulation.

      • Connection rules are are no based on a primitive connect function that only connects two entities with each other. On top of that, any connection strategy can be implemented.

    • Simulation Manager:

      • Simulators written in Python 3 can be executed in process.

      • Simulators can be started as external processes.

      • Mosaik can connect to an already running instance of a simulator. This can be used as a replacement for the now gone platform manager.

    • Simulation execution:

      • The simulation is now event-based. No schedule and no synchronization points need to be computed.

      • Simulators can have different and varying step sizes.

  • Mosaik ecosystem:

1.1 – 2013-10-25

  • [NEW] New API for control strategies.

  • [NEW] Mosaik can be configured via environment variables.

  • [NEW] Various changes and improvements implemented during Steffen’s dissertation.

1.0 – 2013-01-25

Mosaik 1 was nearly a complete rewrite of the previous version and already incorporated many of the concepts and features described in Steffen Schütte’s Phd thesis.

It used mosl, a DSL implemented with Eclipse and xtext, to describe simulators and scenarios. Interprocess communication was done with ZeroMQ and JSON encoded messages.

0.5 – 2011-08-22

This was the first actual version of mosaik that actually worked. However, the simulators we were using at that time were hard coded into the simulation loop and we used XML-RPC to communicate with the simulators.