Opened 6 years ago
Last modified 6 years ago
#4767 assigned defect
Number of intervals is influencing whether simulation run is successful
| Reported by: | Christian Kral <dr.christian.kral@…> | Owned by: | wbraun |
|---|---|---|---|
| Priority: | high | Milestone: | Future |
| Component: | Run-time | Version: | v1.13.0-dev-nightly |
| Keywords: | Cc: | ssuer@… |
Description
Please consider the attached example of a controlled DC machine that I am using in my classes. One of my students ran into a problem when simulating this model.
Simulation setting 1 (as attached)
experiment(StartTime = 0, StopTime = 1.5, Tolerance = 1e-06, Interval = 0.00075)
The simulation fails with the error message:
LOG_SUCCESS | info | <p>The initialization finished successfully without homotopy method.</p> assert | debug | <p>Simulation terminated due to too many, i.e. 20, event iterations.<br> This could either indicate an inconsistent system or an undersized limit of event iterations.<br> The limit of event iterations can be specified using the runtime flag '–mei=<value>'.</p> stdout | error | <p>Simulation process failed. Exited with code 255.</p>
I follow the suggestion and set -mei=1000: This results in:
stdout | error | <p>Simulation process failed. Exited with code 255.</p>
Simulation setting 2
experiment(StartTime = 0, StopTime = 1.5, Tolerance = 1e-06, Interval = 7.5e-05)
The simulation runs fine with some warnings, however.
LOG_SUCCESS | info | <p>The initialization finished successfully without homotopy method.</p> LOG_NLS_V | warning | <p>Warning: maximal number of iteration reached but no root found</p>
Simulations results are displayed correctly and the simulation looks OK.
Conclusions
I already experienced a couple times, that the actual number of intervals heavily influences the success of a simulation run. This makes it very difficult in a teaching situation to identify the problem and find a proper solution. The attached model now represents a reproducible case of the described issue.
This issue occurred at version 1.12.0 (on Windows machine). I double checked the issue right now at version
OMEdit 1.13.0~dev-101-ga45068d Connected to OpenModelica 1.13.0~dev-632-g450ec7c
on a Linux 64bit machine.
Attachments (1)
Change History (2)
Changed 6 years ago by Christian Kral <dr.christian.kral@…>
comment:1 Changed 6 years ago by adeas31
- Component changed from OMEdit to Run-time
- Owner changed from adeas31 to wbraun
- Status changed from new to assigned
Example demonstrating the issue