I am trying to solve an optimization problem.
I have described the problem in Optimica and this seems to work for the input signals.
The problem I have is when I try to optimize parameters.
According to the jmodelica manual (Which is the only Optimica reference I could find) parameters are optimized for if they have the attribute "free=true". But this seems to be not allowed in OpenModelica. It fails with the error "Modified element free not found in class Real".

So I am wondering if there is some other way to optimize parameters? I am especially interested in optimizing the initial values of some states.