3_3_model_exchange_schema.adoc

FMI Description Schema

This is defined in 2.2. Additionally, the Model Exchange-specific element "ModelExchange" is defined in the next section.

Model Exchange FMU (ModelExchange)

If the XML file defines an FMU for Model Exchange, element "ModelExchange" must be present. It is defined as:

The following attributes are defined (all of them are optional, with exception of modelIdentifier):

Attribute Name	Description
modelIdentifier	Short class name according to C syntax, for example, "A_B_C". Used as prefix for FMI functions if the functions are provided in C source code or in static libraries, but not if the functions are provided by a DLL/SharedObject. modelIdentifier is also used as name of the static library or DLL/SharedObject. See also [header-files-and-naming-of-functions].
needsExecutionTool	If true, a tool is needed to execute the model and the FMU just contains the communication to this tool. [Typically, this information is only utilized for information purposes. For example, when loading an FMU with needsExecutionTool = "true", the environment can inform the user that a tool has to be available on the computer where the model is instantiated. The name of the tool can be taken from attribute generationTool of fmiModelDescription.]
completedIntegratorStepNotNeeded	If true, function fmi3CompletedIntegratorStep need not be called (this gives a slightly more efficient integration). If it is called, it has no effect. If false (the default), the function must be called after every completed integrator step, see [evaluation-of-model-equations].
canBeInstantiatedOnlyOncePerProcess	This flag indicates cases (especially for embedded code), where only one instance per FMU is possible (multiple instantiation is default = false; if multiple instances are needed and the flag canBeInstantiatedOnlyOncePerProcess = "true", the FMUs must be instantiated in different processes).
canNotUseMemoryManagementFunctions	If true, the FMU uses its own functions for memory allocation and freeing only. The callback functions allocateMemory and freeMemory given in fmi3Instantiate are ignored.
canGetAndSetFMUState	If true, the environment can inquire the internal FMU state and can restore it. That is, functions fmi3GetFMUState, fmi3SetFMUState, and fmi3FreeFMUState are supported by the FMU.
canSerializeFMUState	If true, the environment can serialize the internal FMU state, in other words, functions fmi3SerializedFMUStateSize, fmi3SerializeFMUState, fmi3DeSerializeFMUState are supported by the FMU. If this is the case, then flag canGetAndSetFMUState must be true as well.
providesDirectionalDerivative	If true, the directional derivative of the equations can be computed with fmi3GetDirectionalDerivative

The flags have the following default values.

boolean: false
unsignedInt: 0

Example XML Description File

When generating an FMU from the hypothetical model "MyLibrary.SpringMassDamper", the XML file may have the following content:

link:examples/model_exchange.xml[role=include]