[petsc-users] How to set newton iteration as LU factor once and use LU result as PC

[Barry Smith]

  From the manual page 

  SNESSetLagPreconditioner - Determines when the preconditioner is rebuilt in the nonlinear solve.

   Logically Collective on SNES

   Input Parameters:
+  snes - the SNES context
-  lag - -1 indicates NEVER rebuild, 1 means rebuild every time the Jacobian is computed within a single nonlinear solve, 2 means every second time
         the Jacobian is built etc. -2 indicates rebuild preconditioner at next chance but then never rebuild after that


On Sep 30, 2012, at 12:20 PM, Jed Brown <jedbrown at mcs.anl.gov> wrote:

> -snes_lag_preconditioner LAG
> 
> where LAG is the number of iterations to lag the factorization.
> 
> On Sun, Sep 30, 2012 at 1:14 AM, Gong Ding <gdiso at ustc.edu> wrote:
> Hi,
> I'd like to try following strategy:
> For a nonlinear solver, at the first Newton step, do a complete LU factorization, and use the factorized matrix as preconditioner matrix in the following iteration.
> 
> How to implement this in petsc?
> 
> Gong Ding
> 
> 
> 
> 
> 
>