BackendDAEUtil.tryToSolveOrDerive don't use functionTree

[Vitalij Ruge]

Differentiate.differentiateExpSolve,ExpressionSolve.solve2 in tryToSolveOrDerive need for correct handling of functions the functionTree.

Example:

model testTearing
  function f
    input Real t;
    output Real y;
  algorithm
    y := 2 * t;
  end f;

  Real a annotation(tearingSelect = always);
  Real b;
  Real _a annotation(tearingSelect = always);
  Real _b;
equation
  a = b + f(b);
  b = sin(a) + 3 * f(b);
  _a = _b + 2 * _b;
  _b = sin(_a) + 3 * 2 * _b;
end testTearing;

It should be possible to find same tearing for a,b loke for _a,_b

[Lennart Ochel]

Can you provide a (small) test case?

[Lennart Ochel]

You put yourself as owner. Does it mean that you are working on this?

[Lennart Ochel]

You are right, once the functionTree is passed through the call hierarchy, the example from the description works as expected. This are my changes: ​ec9085. Should I push the commit, or would you like to fix it differently?

[Vitalij Ruge]

Good!
The Output value for the functionTree is missing.
OM should remember function derivatives in functionTree.

[Vitalij Ruge]

proposal:
If possible extends you changes for output functionTree.
In the next step we should extend the outputs from Differentiate.differentiateExpSolve
and ExpressionSolve.solve2.

[Lennart Ochel]

Do you want something like ​0a05f1 and ​da9f032?
I would leave ExpressionSolve.solve2 for #3512.

[Vitalij Ruge]

yes :).
It would nice to have getAdjacencyMatrixEnhancedScalar update shared with functionTree and return new shared e.g. for selectStatesWork1 and then selectStatesWork or for tearingSystemWork ....

Otherwise we losing the information in the functionTree?? (I don't know)

[Lennart Ochel]

The changes causes problems for some models:

./simulation/libraries/3rdParty/ThermoPower/Bug2537.mos
./simulation/libraries/3rdParty/ThermoPower/ThermoPower.Examples.CISE.CISESim2States120501.mos
./simulation/modelica/initialization/OverdeterminedInitialization.Fluid.DynamicPipesSeriesLargeNSteadyStateInitial.mos