Now using the DFBDF solver… It works so much better than IDA!
About 2.4 times less memory usage than IDA and much faster AND much more accurate!
Testcase: Run a flight simulation for 460s using 50ms time steps. The time in ms below is the time for finding a solution for one time step. The relative error was set to 0.0005 for both solvers. The state vector had 66 elements, a Ryzen 7950X CPU was used.
| Solver | Mem usage [GB] | Time in ms (av/max) |
|---|---|---|
| DFBDF | 11.3 | 0.78 / 8.1 |
| IDA | 27.0 | 3.55 / 13.8 |
The IDA solver was - in difficult situations - unstable, resulting in an additional error of about 1.8~\% for the tether force, the DFBDF solver is perfectly stable.