Creating FMU with option -d=-disableDirectionalDerivatives makes fmi2Instantiate() crash.

[silvano.seva@…]

I'm trying to setup a simple system composed by a Model Exchange FMU coupled to an implicit euler solver. To do this, I need to call the fmi2GetDirectionalDerivative function, which is available if the FMU is generated from the modelica source using the "-d=-disableDirectionalDerivatives" option.
However, this makes the fmi2Instantiate() crash with a segmentation fault, which I traced (using the crash report informations and objdump) to an issue inside the function FmiTest_Model_initialAnalyticJacobianFMIDER, generated by OpenModelica.

I've attached a minimal example. The steps to reproduce the issue are:

• unzip the folder
• run "cmake ." inside it to setup the building environment (it requires the pugixml library to be installed)
• running "make" and then "./fmitest" with files as-is make the program crash
• editing the 6th line of file "buldfmi.mos" so that it does not contain anymore the option "-d=-disableDirectionalDerivatives", then issuing "make clean" followed by "make" and "./fmitest" will not produce a program crash.

[silvano.seva@…]

Source files

[Andreas Heuermann]

I was able to confirm your example and recreated a minimal working example (so I don't have to add pugixml every time).

loadModel(Modelica); getErrorString();
setCommandLineOptions("-d=newInst,-disableDirectionalDerivatives"); getErrorString();
buildModelFMU(Modelica.Electrical.Analog.Examples.Rectifier, version="2.0", fmuType="me_cs", platforms={"static"}); getErrorString();
system("OMSimulator Modelica.Electrical.Analog.Examples.Rectifier.fmu"); getErrorString();

The problem is probably that the fmi jacobian doesn't get allocated at all.
In SimulationRuntime/fmi/export/openmodelica/fmi2_model_interface.c.inc

  /* allocate memory for Jacobian */
  comp->_has_jacobian = 0;
  comp->fmiDerJac = NULL;
  if (comp->fmuData->callback->initialPartialFMIDER != NULL){
    if (! comp->fmuData->callback->initialPartialFMIDER(comp->fmuData, comp->threadData, comp->fmiDerJac)) {
      comp->_has_jacobian = 1;
    }
  }

Adding

  if (jacobian == NULL) {
    jacobian = (ANALYTIC_JACOBIAN*) calloc(1,sizeof(ANALYTIC_JACOBIAN));
  }

manually solves the initialization.
I will polish my solution a bit and finalize it tomorrow. Maybe deallocating memory at the end would be a good idea.

[anonymous]

Thank you, applying your solution makes everything working.
I leave to you the decision about closing this issue as solved or not.

[Andreas Heuermann]

Did you try today's nightly build? The fix should be available as of today.
See ​PR 770.

If everything is working you can just close this issue.

[Francesco Casella]

@silvano, if you open a ticket and you are happy with the outcome, you can close it yourself, unless there are other pending issues.