Add required_intermediate_variables to instantiate_fmu() (#851)

fixes #840

Author: t-sommer

src/fmpy/fmi1.py

@@ -281,7 +281,7 @@ def struct_to_str(s):
                     v = v.value
                 a += hex(0 if v is None else v)
             elif t == c_bool:
-                a += str(v.value)
+                a += str(v.value) if hasattr(v, "value") else str(v)
             elif t == POINTER(c_uint):
                 # value references
                 if v is None:

src/fmpy/fmi3.py

@@ -176,7 +176,7 @@ def fmi3InstantiateCoSimulation(
         self,
         instanceName: fmi3String | bytes,
         instantiationToken: fmi3String | bytes,
-        resourcePath: fmi3String | bytes,
+        resourcePath: fmi3String | bytes | None,
         visible: fmi3Boolean | bool,
         loggingOn: fmi3Boolean | bool,
         eventModeUsed: fmi3Boolean | bool,
@@ -1898,12 +1898,18 @@ def instantiate(
         earlyReturnAllowed=False,
         logMessage=None,
         intermediateUpdate=None,
+        requiredIntermediateVariables=None,
     ):
         # save callbacks from GC
         self.logMessage = fmi3LogMessageCallback(
             printLogMessage if logMessage is None else logMessage
         )
 
+        if requiredIntermediateVariables is None:
+            requiredIntermediateVariables = (fmi3ValueReference * 0)()
+        else:
+            requiredIntermediateVariables = (fmi3ValueReference * len(requiredIntermediateVariables))(*requiredIntermediateVariables)
+
         if intermediateUpdate is None:
             self.intermediateUpdate = fmi3IntermediateUpdateCallback()
         else:
@@ -1919,8 +1925,8 @@ def instantiate(
             fmi3Boolean(loggingOn),
             fmi3Boolean(eventModeUsed),
             fmi3Boolean(earlyReturnAllowed),
-            None,
-            0,
+            requiredIntermediateVariables,
+            len(requiredIntermediateVariables),
             fmi3InstanceEnvironment(),
             self.logMessage,
             self.intermediateUpdate,

src/fmpy/simulation.py

@@ -799,7 +799,21 @@ def simulate_fmu(filename,
     return result
 
 
-def instantiate_fmu(unzipdir, model_description, fmi_type=None, visible=False, debug_logging=False, logger=None, fmi_call_logger=None, library_path=None, early_return_allowed=False, event_mode_used=False, intermediate_update=None, require_functions=True):
+def instantiate_fmu(
+        unzipdir,
+        model_description,
+        fmi_type=None,
+        visible=False,
+        debug_logging=False,
+        logger=None,
+        fmi_call_logger=None,
+        library_path=None,
+        early_return_allowed=False,
+        event_mode_used=False,
+        intermediate_update=None,
+        require_functions=True,
+        required_intermediate_variables=None
+    ):
     """
     Create an instance of fmpy.fmi1._FMU (see simulate_fmu() for documentation of the parameters).
     """
@@ -855,7 +869,8 @@ def instantiate_fmu(unzipdir, model_description, fmi_type=None, visible=False, d
             fmu = fmi3.FMU3Slave(**fmu_args)
             fmu.instantiate(visible=visible, loggingOn=debug_logging, eventModeUsed=event_mode_used,
                             earlyReturnAllowed=early_return_allowed, logMessage=logger,
-                            intermediateUpdate=intermediate_update)
+                            intermediateUpdate=intermediate_update,
+                            requiredIntermediateVariables=required_intermediate_variables)
 
     elif fmi_type in [None, 'ModelExchange'] and model_description.modelExchange is not None: