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Mosaik is a flexible Smart-Grid co-simulation framework.

Project description


Mosaik is a simulation compositor for Smart Grid simulations.

It lets you re-use existing simulators and couple them to simulate large-scale Smart Grid scenarios. Mosaik offers powerful mechanisms to specify and compose these scenarios.

Version: 2.5.2

License: LGPL


Pipeline status Coverage Report Libraries status License badge PyPI version Python Versions


A simple demo scenario with mosaik:

>>> import mosaik
>>> sim_config = {
...     'ExampleSim': {'python': 'example_sim.mosaik:ExampleSim'},
... }
>>> def create_scenario(world):
...     simulator_1 = world.start('ExampleSim')
...     simulator_2 = world.start('ExampleSim')
...     a_set = [simulator_1.A(init_val=0) for i in range(3)]
...     b_set = simulator_2.B.create(2, init_val=0)
...     for i, j in zip(a_set, b_set):
...         world.connect(i, j, ('val_out', 'val_in'))
>>> world = mosaik.scenario.World(sim_config)
>>> create_scenario(world)
Progress: 25.00%
Progress: 50.00%
Progress: 75.00%
Progress: 100.00%


Mosaik requires Python >= 3.4. Use pip to install it, preferably into a virtualenv:

$ pip install mosaik

Documentation, Source Code and Issues

The documentation is available at

Please report bugs and ideas for improvement to our issue tracker.


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 match with mosaik’s major version. The minor part may be lower or equal to mosaik’s minor version.

  • [FIX] Various minor fixes and stability improvements.

  • [FIX] Various documentation updates and fixes.

2.1.2 – 2014-10-29

  • [FIX] World.shutdown() now checks if the socket still exists before attempting to close it.

  • [FIX] Fixed a bug that made the last extra method of a simulator shadow all previous ones.

2.1.1 – 2014-10-28

  • [NEW] now prints a warning if you forget to connect a simulator’s entities.

  • [FIX] Fixed some problems with the data-flow cache.

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

  • Mosaik 2 is a complete rewrite of mosaik 1 in order to improve its maintainability and flexibility.

  • 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.

    • The database is now a separate package, see mosaik-hdf5.

    • The old web UI is gone.

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

    • mosaik Sim 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, set_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:

You can find information about older versions on the history page


The original concepts for mosaik were developed by Steffen Schütte and Stefan Scherfke.

The author of mosaik version 2 is Stefan Scherfke.

Okko Nannen and Florian Schloegl joined the team in May / July 2014. André El-Ama joined the Team Juli / 2017

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