[petsc-users] GAMG and near-null-space when applying Dirichlet Conditions

[Manav Bhatia]

Hi, 

    I typically apply Dirichlet BCs by modifying the Jacobin and rhs: zero constrained rows of matrix with 1.0 at diagonal, and zero corresponding rows of rhs. 

    While using GAMG, is it still recommended to provide the near-null space (given that the zero-eigenvalues have been removed by specification of DIrichlet BCs)?

    If that information is still needed, should the vectors be modified in any manner to be consistent with the Dirichlet BCs? 

Thanks,
Manav