# Improve possible vtkMath bottleneck
**URL:** https://discourse.vtk.org/t/improve-possible-vtkmath-bottleneck/8913
**Category:** Development
**Created:** [July 9, 2022, 1:05pm UTC](https://discourse.vtk.org/t/improve-possible-vtkmath-bottleneck/8913 "2022-07-09T13:05:34Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@mau\_igna\_06](https://discourse.vtk.org/u/mau_igna_06)
#### Post date: [July 9, 2022, 1:05pm UTC](https://discourse.vtk.org/t/improve-possible-vtkmath-bottleneck/8913/1 "2022-07-09T13:05:34Z")
Hi.
While using Slicer with VerySleepy I noticed it spent a lot of time on `vtkJacobiN`. I did a quick search and there is a faster convergence algorithm called GaussSeidel.
You can see more here:
> **[chap\_10\_2.pdf](https://college.cengage.com/mathematics/larson/elementary_linear/5e/students/ch08-10/chap_10_2.pdf)**
>
> 123.72 KB
I implemented it, built Slicer and used it, and the change doesn’t appear to break anything…
>
I leave it to VTK experts to make benchmarks of how much it improves… According to the book of the link I posted:
> GaussSeidel 5 iterations have the same accuracy than Jacobi 7 iterations.
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### Author:  [@will.schroeder](https://discourse.vtk.org/u/will.schroeder)
#### Post date: [July 9, 2022, 2:05pm UTC](https://discourse.vtk.org/t/improve-possible-vtkmath-bottleneck/8913/2 "2022-07-09T14:05:23Z")
Fantastic thanks for doing this work. I’m on vacation the next couple of weeks but I’m sure someone will take a look soon.
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### Author:  [@mau\_igna\_06](https://discourse.vtk.org/u/mau_igna_06)
#### Post date: [July 18, 2022, 5:13pm UTC](https://discourse.vtk.org/t/improve-possible-vtkmath-bottleneck/8913/3 "2022-07-18T17:13:18Z")
I have looked at this more in depth, I was wrong, there are no visible improvements… Sorry for the buzz… I’ll attach some profiling I did later
BTW: the algorithm for diagonalization has the same name as the algorithm for solving linear equations that confused me at first.