EvaluateFunctions.getStatementLHSScalar generates too large lists

[Per Östlund]

There seems to be some issues with how EvaluateFunctions.getStatementLHSScalar generates the list of assigned scalars in a statement. This affects the HelmholtzMedia library in particular, for example the model HelmholtzMedia.Examples.ConvergenceTest.SinglePhase_setState_b (note: only works with -d=newInst).

SinglePhase_setState_b uses the function HelmholtzMedia.Interfaces.PartialHelmholtzMedium which contains two large if-statements. When EvaluateFunctions.evaluateFunctions_updateStatement processes the second of these if-statements it uses getStatementLHSScalar to generate a list of outputs (currently EvaluateFunctions.mo:2664):

  lhs_expl := List.fold1(statements, getStatementLHSScalar, funcTree, {});

This generates a list of 2,874,978 expressions, which seems a bit excessive. Obviously this causes the compiler to slow to a crawl, and this is just one of many such lists generated by getStatementLHSScalar. The list of outputs generated seem to be full of gibberish such as f.rt.r.i.liq.s.rd.rt.r.it.liq.d.Tsat.Tsat, which I assume isn't intended.

(I optimized the code a bit in 765d7e8 since List.unique would otherwise take forever on the large lists generated, but the huge lists generated are still a big issue.)

[Per Östlund]

Possibly fixed in 14f391f, we'll see what the outcome of the library testing is. The largest generated list now contains 129 elements, rather than close to 3 million. But instead of running out of time or memory like before the mentioned model now triggers a stack overflow, so there's still some issues when it comes to HelmholtzMedia.

[matthis.thorade@…]

Since this commit
​https://github.com/OpenModelica/OpenModelica/commit/80ac1a491c0b0bc5c15e878636f0f0245295830d
most models are now compiling fine, and most also simulate, some fail during initialization:
​https://libraries.openmodelica.org/branches/newInst/HelmholtzMedia/HelmholtzMedia.html

[Francesco Casella]

I guess we can close this ticket.

Regarding the initialization issues, you may want to wait until #5770 is fixed.