Running reference model BouncingBall.fmu causes infinite prints (error: [doStep] SUNDIALS_ERROR: CVode() failed with flag = -3)

[GorbadPS3]

Description

Running reference model BouncingBall.fmu causes infinite prints in console:

[CVODE ERROR]  CVode
  At t = 0.446 and h = 0.001, the error test failed repeatedly or with |h| = hmin.

error:   [doStep] SUNDIALS_ERROR: CVode() failed with flag = -3

Steps to reproduce the behavior

1. Download https://github.com/modelica/Reference-FMUs/releases/tag/v0.0.29
2. Unzip
3. Locate Reference-FMUs-0.0.29/2.0/BouncingBall.fmu
4. Run the following OMSimulator.dll commands:

        oms_setTempDirectory("C:/local/foobar/temp");
    	oms_newModel("m");
    	oms_addSystem("m.r", oms_system_sc);
    	oms_addSubModel("m.r.BB", "./Reference-FMUs-0.0.29/2.0/BouncingBall.fmu");
    	oms_setResultFile("m", "C:/local/foobar/result/results.csv", 100);
    	oms_setStopTime("m", 1.0);
    	oms_setStartTime("m", 0.0);
    	oms_setFixedStepSize("m.r", 0.001);
    	oms_instantiate("m");
    	oms_initialize("m");
    	oms_simulate("m");
    	oms_terminate("m");
    	

Notice that as soon as you call "oms_simulate" the console will start filling with errors.

Expected behavior

The simulation should finish as expected. Running OMSimulator.exe from command-line works fine:

OMSimulator.exe --startTime=0.0 --stopTime=1.0 --resultFile="C:/local/foobar/result/results.csv" "./Reference-FMUs-0.0.29/2.0/BouncingBall.fmu"

Version and OS

• Version: v2.1.1.post247-g614c663-mingw-notlm-debug
• OS: Win11, 64bit

[arun3688]

@GorbadPS3 you cannot use oms_setFixedStepSize("m.r", 0.001); when simulating a Strongly connected Components which is basically a ME fmu's see the documentation here https://openmodelica.org/doc/OpenModelicaUsersGuide/1.22/omsimulator.html#setfixedstepsize, So change the System type to oms_system_wc, see below

oms_addSystem("m.r", oms_system_wc);
or if you want to simulate as oms_system_sc, you must remove the oms_setFixedStepSize in your lua script,

If you want to set the stepSizes for SC system you should use oms_setVariableStepSize, https://openmodelica.org/doc/OpenModelicaUsersGuide/1.22/omsimulator.html#setvariablestepsize

[GorbadPS3]

Hi,

Thanks, that makes sense. What doesn't make sense is OMSimulator going into an infinite loop. The code should be able to notice the issue and return oms_status_error in cases like this.