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Load an FMU

First, retrieve the path to the example FMU deviation.fmu.

import otfmi
import otfmi.example.utility

path_fmu = otfmi.example.utility.get_path_fmu("deviation")

Loading an FMU only requires the FMU name or path.

model = otfmi.fmi.load_fmu(path_fmu)

If the FMU is both ModelExchange and CoSimulation, the CoSimulation type is favoured. This choice, opposite to PyFMI’s default, enables the CoSimulation to impose a solver not available in PyFMI.

otfmi drives the FMU through an FMI backend, PyFMI by default, FMPy as a fallback. Both expose the same interface, so the code below is backend-independent.

print(f"backend = {otfmi.backend.BACKEND}")

backend = pyfmi

Backend-specific loading options can be passed on to otfmi. With PyFMI, for instance, the log file name can be specified:

model = otfmi.fmi.load_fmu(path_fmu, kind="CS", log_file_name="deviation.log")

Note

otfmi load_fmu is an overlay of the backend load_fmu function. Hence the FMU loaded here upper benefits of all the backend methods.

The model object also gives access to the underlying backend model, e.g. to inspect the variables it exposes:

sorted(model.get_model_variables().keys())

['E', 'F', 'I', 'L', 'der(_D_outputAlias_y)', 'y']