Francesco Casella

Unfortunately it didn't help much, see [regression report](https://libraries.openmodelica.org/branches/history/newInst-newBackend/2024-12-04%2015:46:06..2024-12-05%2015:28:29.html). In fact, the ScalableTestGrids models that were compiling now fail at the SimCode stage.

Maybe you should try out some of those models before making the PR 😃

@phannebohm reports that the apparent regression is actually an improvement, because previously sparsity pattern generation was not even attempted, now it is mostly working, save for some bugs that will...

Update: after #13340, the [MWE](https://github.com/OpenModelica/OpenModelica/issues/13058#issuecomment-2515080951) by @phannebohm runs successfully with the NB. Unfortunately, ScalableTestGrids models cannot yet be compiled. If you check, e.g., [ScalableTestGrids.Models.Type1.Type1_N_1_M_1](https://libraries.openmodelica.org/branches/newInst-newBackend/ScalableTestGrids_noopt/files/ScalableTestGrids_noopt_ScalableTestGrids.Models.Type1.Type1_N_1_M_1.err), the following error is reported during...

I guess the issue regarding the sparsity pattern can be considered fixed. I'll open a separate one regarding the LHS Complex record. See #13980.

I made a preliminary investigation, unfortunately it seems that the C runtime doesn't have a single mechanism to handle the scaling of residuals. The KINSOL solver implements the mechanism discussed...

I checked @HansOlsson's pull request PR #4263 and it looks good to me. @arunkumar-narasimhan please back-port this to maint/4.1.0

This issue is actually a regression from v.4.0.0 but I also marked it with the 4.1.0-dev label so we don't forget about it

@Esther-Devakirubai please back-port this to maint/4.1.x, then you can close this ticket. Thanks!

@Esther-Devakirubai ping, please back-port this to maint/v4.1.x