Multirate methods

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Joined: 2014-05-13
Multirate methods

Hello Everyone

I am working on multirate methods where, if the error estimates for some of the variables are higher than tolerances, only those are re-integrated while interpolating the others. I would like to implement this in FMI. Is there a way to supply a sublist of variables to the function get_derivatives() to get the derivatives of only those variables?

If not, then could you suggest me some ways of doing this? Can I write my own piece of code to do this? How would I integrate this in the FMU that I want to simulate?

EDIT: There is a function get_output_derivatives() in FMI for Co-Simulation. According to the description this takes a list of variables and the order as input and returns the derivatives. What we need is to extend this capability of returning only those derivatives which are asked for, in FMI for model excahnge, because this is relevant to multirate solvers. 

So, if this was to be done then the changes have to be made in the FMI library itself, right? Am I right about this? How might one go about doing this?



P.S. I realize that the last part of my question might not really be answerable on this forum, but could you please direct me to other forums/tutorials or material on the internet where I can find the required information.