Thanks again for your time and patience.
I am using the Matlab interface on Windows.
Regarding your comments, I must admit I did not quite understand your comment:
“The .set() routine with field “x” and stage index should do the job though.”.
Was this referring to the initialization suggestion?
And are you referring to Casadi, Ipopt or IDAS?
Regarding time_tot and time_sim: I guess that is what Ipopt prints on the console at higher verbosity levels (still trying to figure out how I can bring the CaSaDi solver in the Matlab Interface to give this as an output too). Anyhow, since I typically get something like the following output of a single iteration:
Total CPU secs in IPOPT (w/o function evaluations) = 0.073
Total CPU secs in NLP function evaluations = 1.572
Now before investing a lot of time and effort into solving the problem with ACADOS, and I don’t plan to run the code on an embedded platform, I would need more understanding of where the time is lost.
Is it solving the DAE in general? Then I would not expect ACADOS to bring any benefit if under the hood, ACADOS solver needs similar amount of function evaluations wtih the same DAE solver.
Is it because in my setting, using the Matlab Interface, the DAE evaluations (including the sensitivities) are just by far slower running in the virtual environment? I am clearly lacking understanding of what exactly is already running a C-code in CasADi and what will be differnt here.
Is it because ACADOS solver will need by far less function evaluations? This seems to be case using the RTI scheme, where one would stop after the first iteration - but this only works for quadradic costs, right?
Another path I am considering to take is formulating the problem with a collocation method to get around the slow solution of the DAEs, but this is new to me as well.
I do not expect you to answer all my questions, and I know this cannot be answered in general.
Nevertheless, it might be helpful for you to know which kind of questions unexerienced users like me are facing.
I will try open a new thread with this topic, since I belief more users might have the same challenges.