[petsc-users] Can BDDC precondtioner be used as a blackbox?

[459543524 via petsc-users]

Sir.


I want to using BDDC solve a linear system. I already have a matrix A and 
vector b. I want to solve Ax=b.


I have no idea how BDDC works. I just want to experience the performance of 
BDDC preconditioner.


I wonder does the BDDC precondtioner can be used as a black box as other 
preconditioner (such AMG or ILU)?


For AMG, we can use simple follow code:
------------------
    Mat A;
    Vec x,b;
    KSP ksp;
    PC pc;


    KSPSetOperators(ksp, A, A);
    KSPGetPC(ksp, &pc);
    PCSetType(pc, PCHMG);
    PCHMGSetInnerPCType(pc, PCGAMG);
    PCHMGSetReuseInterpolation(pc, PETSC_TRUE);
    PCHMGSetUseSubspaceCoarsening(pc, PETSC_TRUE);
    PCHMGUseMatMAIJ(pc, PETSC_FALSE);
    PCHMGSetCoarseningComponent(pc, 0);

    KSPSolve(ksp, b, x);
------------------


For ILU, we can use simple follow code:
------------------
    Mat A;
    Vec x,b;
    KSP ksp;
    PC pc;


    KSPSetOperators(ksp, A, A);
    KSPSetType(ksp, KSPGMRES);
    KSPGetPC(ksp, &pc);
    PCSetType(pc, PCILU);

    KSPSolve(ksp, b, x);
------------------



I found ex.59 is a little complicated for me to understand if I do not BDDC 
background.


Can BDDC precondtioner be used as a blackbox?


Thanks for your time.


Xu Hui