[petsc-users] Preconditioning in matrix-free methods

[Konstantinos Kontzialis]

Dear all,

 

I am trying to use preconditioning in SNES within a matrix free conext. I use petsc 3.3 and whenever I use the option

-snes_mf_operator I get the following error:

 

Must call DMShellSetMatrix() or DMShellSetCreateMatrix()

 

I code the following:

 

      call TSCreate (petsc_comm_world, ts_mhd, ierpetsc)     
c          
      call TSSetProblemType (ts_mhd, TS_NONLINEAR, ierpetsc)    
c
      call TSSetIFunction ( ts_mhd, res_mhd, residual_mag,     
     @  PETSC_NULL_OBJECT, ierpetsc )     
c    
      call TSSetSolution( ts_mhd, Bmagnetic_pet, ierpetsc )
c
      call TSSetMaxSNESFailures ( ts_mhd, -1, ierpetsc)
c             
      call TSGetSNES (ts_mhd, snes_mhd, ierpetsc )

 

      call MatCreateSNESMF ( snes_mhd, J_mf, ierpetsc )     
c     
      call SNESSetJacobian ( snes_mhd, J_mf, M_mhd,
    @ SNESDefaultComputeJacobianColor, fdcoloring,
    @ ierpetsc )

 

Has anyone any suggestions on what to do?

 

Kostas