IBPSA.Fluid.Examples.FlowSystem.Simplified1
Flow system in which the nonlinear system of equation cannot be solved during the time integration.
In Dymola, the model fails to simulate with CVOde 1E-6, but it works if changed to 1E-8. For example, the following command leads to a successful simulation:
simulateModel("IBPSA.Fluid.Examples.FlowSystem.Simplified1",
stopTime=1000, method="Cvode", tolerance=1e-08, resultFile="Simplified1");
See also FlowSystemDymola, which uses an earlier version of the IBPSA library, with a different pump
model, which works with Dymola 2024x. It appears that the numerics of the model changed to the point
where the solver now fails to converge, also if the tolerance is changed to 1E-8.
| Model | IBPSA.Fluid.Examples.FlowSystem.Simplified1 |
| Tool | Dymola 2024x |
| OS | Linux Ubuntu 20.04 |
| Status | open |
| Setup |
git clone git@github.com:ibpsa/modelica-ibpsa.git git checkout e70093d8a8fac05427d43f2f008a7e731fadd64e |
| Command |
cd modelica-ibpsa echo "openModel(\"IBPSA/package.mo\", changeDirectory = false);" > run.mos echo "simulateModel(\"IBPSA.Fluid.Examples.FlowSystem.Simplified1\", stopTime=1000, method=\"Cvode\", tolerance=1e-06, resultFile=\"Simplified1\");" >> run.mos echo "exit();" >> run.mos dymola run.mos cat dslog.txt |
| Log message |
Model: IBPSA.Fluid.Examples.FlowSystem.Simplified1 Integration started at 0 using integration method: cvode from sundials Warning: Failed to solve nonlinear system using Newton solver. Time: 5.344385256591128 Tag: simulation.nonlinear[3] For debugging information enable Simulation/Setup/Debug/Nonlinear solver diagnostics/Detailed logging of failed nonlinear solutions. Warning: Failed to solve nonlinear system using Newton solver. Time: 5.344385256591128 Tag: simulation.nonlinear[3] Warning: Failed to solve nonlinear system using Newton solver. Time: 5.390616987683465 Tag: simulation.nonlinear[3] Warning: Failed to solve nonlinear system using Newton solver. Time: 5.390616987683465 Tag: simulation.nonlinear[3] Warning: Failed to solve nonlinear system using Newton solver. Time: 5.370401854505952 Tag: simulation.nonlinear[3] Warning: Failed to solve nonlinear system using Newton solver. Time: 5.362821179564386 Tag: simulation.nonlinear[3] Previous problem occured when evaluating crossing function, reducing step-size SUNDIALS: CVODE cvRcheck3 At t = 5.36029, the rootfinding routine failed in an unrecoverable manner. Cannot recover from failed crossing function evaluation at time 5 CVode simulation failed Integration terminated unsuccesfully at T = 5 CPU-time for integration : 0.0367098 seconds CPU-time for initialization : 0.00101209 seconds Number of result points : 5 Number of grid points : 3 Number of accepted steps : 43 Number of rejected steps : 1 Number of f-evaluations (dynamics) : 71 Number of non-linear iteration : 58 Number of non-linear convergence failures : 3 Number of Jacobian-evaluations : 5 Number of crossing function evaluations : 46 Number of model time events : 1 Number of state events : 0 Number of step events : 0 Maximum integration order : 4 ERROR: The simulation of IBPSA.Fluid.Examples.FlowSystem.Simplified1 FAILED |