Evan :
PCFactorSetMatSolverPackage(pc_fetd_dt, MATSOLVERMUMPS);
You use mumps' Cholesky.
PCFactorSetShiftType(pc_fetd_dt,MAT_SHIFT_POSITIVE_DEFINITE);
This option only works for PETSc Cholesky, not mumps.
I'm not aware of any option in mumps to add a shift to zero pivot.
I'll send a request to
Dear PETSC Users,
I try to solve a diffusion problem in the time domain. Its system matrix is
theoretically SPD. I use KSPCG solver. Direct MUMPS solver generates a
preconditioner. Thus, within 1-2 iterations, a solution is expected to
converge. Such convergence is observed in most test problems.
On Sun, Sep 28, 2014 at 6:24 PM, Evan Um eva...@gmail.com wrote:
Dear PETSC Users,
I try to solve a diffusion problem in the time domain. Its system matrix
is theoretically SPD. I use KSPCG solver. Direct MUMPS solver generates a
preconditioner. Thus, within 1-2 iterations, a solution is
