pbrubeck
commented
1 year ago This is the output of solver.snes.ksp.pc.view()
PC Object: () 1 MPI process
type: python
Python: firedrake.SCPC
Firedrake custom preconditioner SCPC
Solving linear system using static condensation.
KSP Object: (condensed_field_) 1 MPI process
type: gmres
restart=30, using Classical (unmodified) Gram-Schmidt Orthogonalization with no iterative refinement
happy breakdown tolerance 1e-30
maximum iterations=10000, initial guess is zero
tolerances: relative=1e-05, absolute=1e-50, divergence=10000.
left preconditioning
using PRECONDITIONED norm type for convergence test
PC Object: (condensed_field_) 1 MPI process
type: mg
type is MULTIPLICATIVE, levels=2 cycles=v
Cycles per PCApply=1
Not using Galerkin computed coarse grid matrices
Coarse grid solver -- level 0 -------------------------------
KSP Object: (condensed_field_mg_coarse_) 1 MPI process
type: preonly
maximum iterations=10000, initial guess is zero
tolerances: relative=1e-05, absolute=1e-50, divergence=10000.
left preconditioning
using NONE norm type for convergence test
PC Object: (condensed_field_mg_coarse_) 1 MPI process
type: none
linear system matrix = precond matrix:
Mat Object: 1 MPI process
type: seqaij
rows=2921, cols=2921
total: nonzeros=46601, allocated nonzeros=46601
total number of mallocs used during MatSetValues calls=0
using I-node routines: found 1677 nodes, limit used is 5
Down solver (pre-smoother) on level 1 -------------------------------
KSP Object: (condensed_field_mg_levels_1_) 1 MPI process
type: preonly
maximum iterations=2, nonzero initial guess
tolerances: relative=1e-05, absolute=1e-50, divergence=10000.
left preconditioning
using NONE norm type for convergence test
PC Object: (condensed_field_mg_levels_1_) 1 MPI process
type: none
linear system matrix = precond matrix:
Mat Object: (condensed_field_) 1 MPI process
type: seqaij
rows=2921, cols=2921
total: nonzeros=46601, allocated nonzeros=46601
total number of mallocs used during MatSetValues calls=0
using I-node routines: found 1677 nodes, limit used is 5
Up solver (post-smoother) same as down solver (pre-smoother)
linear system matrix = precond matrix:
Mat Object: (condensed_field_) 1 MPI process
type: seqaij
rows=2921, cols=2921
total: nonzeros=46601, allocated nonzeros=46601
total number of mallocs used during MatSetValues calls=0
using I-node routines: found 1677 nodes, limit used is 5
Locally reconstructing unknowns.
linear system matrix = precond matrix:
Mat Object: () 1 MPI process
type: python
rows=3721, cols=3721
Python: firedrake.matrix_free.operators.ImplicitMatrixContext
Firedrake matrix-free operator ImplicitMatrixContextSeems like the coarse space has the same dimension as the fine space.
The following script attempts to use static condensation (SCPC) as the outer solver and geometric multigrid as the inner solver to solve a continuous Lagrange formuation of Poisson.
The code fails with this error message:
I suspect that the routines to construct interpolators are not set up, and the fine KSP receives a coarse RHS. Another possiblity is that the coarse matrix is discretized directly from the fine Jacobian, as it could be the case that coarsening is not implemented for SLATE Tensors.