# Adding MatDiagonalSet, MatAXPY and MatAYPX

**URL:** <https://community.freefem.org/t/adding-matdiagonalset-mataxpy-and-mataypx/1345>\
**Category:** Feature Request\
**Created:** [November 22, 2021, 3:40pm UTC](https://community.freefem.org/t/adding-matdiagonalset-mataxpy-and-mataypx/1345 "2021-11-22T15:40:57Z")\
**Posts on this page:** 1\
**Showing post:** 10

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**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\
**Post date:** [November 23, 2021, 6:53am UTC](https://community.freefem.org/t/adding-matdiagonalset-mataxpy-and-mataypx/1345/10 "2021-11-23T06:53:44Z")

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Your problem is so tiny that an augmented Lagrangian approach is probably not necessary. Again, first, I would use as a preconditioner a previous LU factorization. Then, try other simple approach (that could work for tiny problems as yours) such as block Jacobi or additive Schwarz.

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