The JModelica.org interface to FMI is written in Python and is intended to be a close copy of the defined C-interface for an FMU and provides classes and functions for interacting with FMUs.
The JModelica.org platform offers a Pythonic and convenient interface for FMUs which can be used to connect other simulation software. JModelica.org also offers a connection to Assimulo, the default simulation package included in JModelica.org so that FMUs can easily be simulated.
The interface is located in
pyfmi.fmi and consist of the class
FMUModel together with methods for unzipping the FMU and for writing the simulation results. Connected to this interface is a wrapper
for JModelica.org's simulation package to enable an easy simulation of the FMUs. The simulation wrapper is located in
In the table below is a list of the FMI C-interface and its counterpart in the JModelica.org Python package. We have adapted
the name convention of lowercase letters and underscores separating words. For methods with no calculations, as for example
fmi(Get/Set)ContinuousStates they are instead of different methods, connected with a property. In the table, a lack of parenthesis indicates that the
method is instead a property.
Table 5.1. Conversion table.
|FMI C-Interface||JModelica.org FMI Python Interface|
|const char* fmiGetModelTypesPlatform()||string FMUModel.model_types_platform|
|const char* fmiGetVersion()||string FMUModel.version|
|void fmiFreeModelInstance(fmiComponent c)||FMUModel.__del__()|
|fmiStatus fmiSetDebugLogging(...)||none FMUModel.set_debug_logging(flag)|
|fmiStatus fmiCompletedIntegratorStep(...)||boolean FMUModel.completed_integrator_step()|
|fmiStatus fmiSetReal/Integer/Boolean/String(...)||none FMUModel.set_real/integer/boolean/string(valueref,values)|
|fmiStatus fmiInitialize(...)||none FMUModel.initialize() (also sets the start attributes)|
|fmiStatus fmiGetDerivatives(...)||numpy.array FMUModel.get_derivatives()|
|fmiStatus fmiGetEventIndicators(...)||numpy.array FMUModel.get_event_indicators()|
|fmiStatus fmiGetReal/Integer/Boolean/String(...)||numpy.array FMUModel.get_real/integer/boolean/string(valueref)|
|fmiStatus fmiEventUpdate(...)||none FMUModel.event_update()|
|fmiStatus fmiGetStateValueReferences(...)||numpy.array FMUModel.get_state_value_references()|
If logging is set to
True the log can be retrieved with the method,
Documentation of the functions can also be accessed interactively from IPython by using for instance,
There is also a one-to-one map to the C-functions, meaning that there is an option to use the low-level C-functions as they
are specified in the standard instead of using our wrapping of the functions. These functions are also located in
FMUModel and is named with a leading underscore together with the same name as specified in the standard.