Linearization support for nonlinear domain decomposition methods

[atgeirr]

Added to have a place for discussion, as for its downstream PR OPM/opm-simulators#3764.

[OPMUSER]

Can this be closed?

[bska]

Can this be closed?

I don't think so. We should rather pick the work back up after the 2022.10 release.

[bska]

This patch no longer applies cleanly. Would you mind rebasing the branch onto the current master sources please?

[atgeirr]

Will update.

[bska]

Following #806 this now has merge conflicts. Please rebase.

[atgeirr]

jenkins build this please

[bska]

I think this looks good apart from a few minor nits and clarifications.

Tangentially, I've noticed that a lot of the code in this module is written as

for (elemIt = ...) {
    const Element& elem = *elemIt;
    use(elem);
}

and that this PR follows that pattern too. Is there a reason, maybe lifetime extension, for creating the Element& instead of using *elemIt directly, especially if use() is just a single statement?

[atgeirr]

Is there a reason, maybe lifetime extension, for creating the Element& instead of using *elemIt directly, especially if use() is just a single statement?

I think mostly readability, better to not deal directly with iterators. And then it has been duplicated everywhere needed. I agree that it is almost pointless when there is just a single usage though! There is one more argument in favour: less change needed to move to a range-for loop over view.elements(), which is something we should probably do anyway.

[atgeirr]

jenkins build this please

[bska]

Thanks a lot for the updates. I think the code looks good now, and I'm prepared to merge the current end state. I noticed one potential refinement, but I'm not insisting that we write it that way. I would appreciate, however, if we could squash down the commit sequence to remove some of the intermediate "[HACK]" and "[WIP]" states.

[atgeirr]

jenkins build this please

[bska]

Thanks a lot for the updates and for squashing down the commit sequence. I'll merge this into the master branch now to enable bringing NLDD in too.