Re: [petsc-users] Solve Linear System with Field Split Preconditioner

[晓峰 何]

Hello Jed,

The saddle point is due to Lagrange multipliers, thus the size of A11 is much 
smaller than A00.



Best Regards,

Xiaofeng


On Sep 26, 2022, at 21:03, Jed Brown 
<j...@jedbrown.org<mailto:j...@jedbrown.org>> wrote:

Lagrange multipliers