KLU wrappers

[ChrisRackauckas]

https://ufdc.ufl.edu/UFE0011721/00001

@andreasnoack @ViralBShah is KLU wrapped in Julia? How would it be accessed through the SuiteSparse wrappers?

[ViralBShah]

Probably not - but can't be more than an afternoon's work. Pinging @Wimmerer to see if he may be able to help.

[rayegun]

I plan to be sure we have complete SuiteSparse coverage this coming week. If it's in there I'll be sure we have it.

[ViralBShah]

Yes, KLU is in SuiteSparse:
https://github.com/DrTimothyAldenDavis/SuiteSparse/tree/master/KLU

It is also perhaps no more than a few days of work to have a native Julia implementation of KLU, which would be very valuable in the long run. Obviously, start with the wrapper, but the Julia version could be someone's GSOC/JSOC project. :-)

[rayegun]

If it's just a few days work I can also do a Julia implementation. But for now expect to see a wrapper towards the end of next week. It'll probably come out with 1.0 of SuiteSparseGraphBLAS.jl

[rayegun]

Is there a way to assign this issue to me?

[ViralBShah]

If it's just a few days work I can also do a Julia implementation

For whoever does this and whenever, the thesis linked above talks about the algorithm. It is basically a straightforward left looking LU. IIRC, it was found that circuit matrices were too unstructured, and all the supernodal and multifrontal methods spent a lot of time looking for structure that didn't exist, and ended up being slow. Having a good implementation of the textbook sparse LU method is what you need. That's what KLU does. If you read the C code, it is pretty compact.

[ViralBShah]

@Wimmerer Are your complete SuiteSparse wrappers going into SuiteSparse.jl or a separate package? Are you auto-generating them with Clang.jl?

[rayegun]

We discussed this in Slack but for records. The plan is to fork SuiteSparse.jl and auto-generate all rather than just some functions. I imagine it will be very time consuming to make Julian wrappers for each function, but I'll start with this capability.

Merging that fork back will depend on 1. Maintaining all current capability, and 2. The timeline for making SuiteSparse.jl a package.

If that can happen quickly then we can probably provide KLU fairly soon. If not we may want to create a temporary package so it's accessible.

[ChrisRackauckas]

Hey @Wimmerer, any update here? See the way the other factorization wrappers are handled.

[rayegun]

I'm going to add KLU.jl to the registry today or tomorrow, so after the 3 day waiting period I'll make a PR here.

It was originally going to be part of SuiteSparse.jl, but it was decided to do separately a few days ago. Just need to finish up a few things to make it suitable standalone.

[ChrisRackauckas]

Now it's got a repo https://github.com/JuliaSparse/KLU.jl 🎉

[ChrisRackauckas]

Completed via #44