Use sparse solvers for event handling in daemode

[Francesco Casella]

The simulation time for models with many when clauses and large implicit systems of equations, which is one class of models where using daemode makes lots of sense, scales as O(N³). See, e.g., the BreakerNetwork and BreakerNetworkDelayed models in the ScalableTestSuite ​https://test.openmodelica.org/libraries/ScalableTestSuite_Experimental/BuildModelRecursive.html

As far as I understand, this is due to the fact that, during event handling, the dynamic equations and the equations of the active when clauses are solved using a dense solver, whose solution time is cubic with the size.

If the equations are linear, the -lssMaxDensity and -lssMinSize values should be used to automatically trigger the use of a sparse solver also in this case. I understand this should be enough to handle the ScalableTestSuite test cases efficiently.

The sparse Kinsol solver should be implemented instead, in order to handle the models with large nonlinear implicit equation systems.

[Martin Sjölund]

Milestone moved to 1.12.0 due to 1.11.0 already being released.

[Francesco Casella]

Milestone moved to 1.13.0 due to 1.12.0 already being released.

[Francesco Casella]

Rescheduled to 1.14.0 after 1.13.0 releasee

[Francesco Casella]

Releasing 1.14.0 which is stable and has many improvements w.r.t. 1.13.2. This issue is rescheduled to 1.16.0

[Francesco Casella]

Retargeted to 1.17.0 after 1.16.0 release

[Francesco Casella]

Retargeted to 1.18.0 because of 1.17.0 timed release.

[Francesco Casella]

Ticket retargeted after milestone closed

[Francesco Casella]

Discussion continues on ​https://github.com/OpenModelica/OpenModelica/issues/4034