PCPBJACOBI

Point block Jacobi preconditioner

Notes

See PCJACOBI for diagonal Jacobi, PCVPBJACOBI for variable-size point block, and PCBJACOBI for large size blocks

This works for MATAIJ and MATBAIJ matrices and uses the blocksize provided to the matrix

Uses dense LU factorization with partial pivoting to invert the blocks; if a zero pivot is detected a PETSc error is generated.

Developer Notes

This should support the PCSetErrorIfFailure() flag set to PETSC_TRUE to allow the factorization to continue even after a zero pivot is found resulting in a Nan and hence terminating KSP with a KSP_DIVERGED_NANORINF allowing a nonlinear solver/ODE integrator to recover without stopping the program as currently happens.

Perhaps should provide an option that allows generation of a valid preconditioner even if a block is singular as the PCJACOBI does.

See Also

KSP: Linear System Solvers, PCCreate(), PCSetType(), PCType, PC, PCJACOBI, PCVPBJACOBI, PCBJACOBI

Level

beginner

Location

src/ksp/pc/impls/pbjacobi/pbjacobi.c

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