Nominal values of iteration variables in linear/non-linear/mixed system solvers

[Lennart Ochel]

The solvers for linear, non-linear and mixed systems are working on wrong variable attributes, e.g. nominal values. This can be investigated using the following model:

   model problem10
     parameter Real xn = 1e5;
     parameter Real yn = 1e-5;
     Real x(start=1.5*xn, nominal=xn);
     Real y(start=1.5*yn, nominal=yn);
   equation
     0 = -(x/xn)*exp(-(x/xn)*(y/yn))-1;
     0 = (y/yn)*exp(-(x/xn)+(y/yn))-1;
   end problem10;

The issue is, that the attributes get copied for the solvers before the parameters are calculated. I already worked out a patch that fixes this problem. Unfortunately, there are models that need to solve non-linear systems to evaluate parameters, see #1651. Because cyclic dependencies in parameter bindings is not allowed, that ticket should get fixed first.