Source code for firedrake.preconditioners.base

import abc

from firedrake_citations import Citations
from firedrake.petsc import PETSc

__all__ = ("PCBase", "SNESBase", "PCSNESBase")


[docs]class PCSNESBase(object, metaclass=abc.ABCMeta): def __init__(self): """Create a PC context suitable for PETSc. Matrix free preconditioners should inherit from this class and implement: - :meth:`initialize` - :meth:`update` - :meth:`apply` - :meth:`applyTranspose` """ Citations().register("Kirby2017") self.initialized = False super(PCSNESBase, self).__init__()
[docs] @abc.abstractmethod def update(self, pc): """Update any state in this preconditioner.""" pass
[docs] @abc.abstractmethod def initialize(self, pc): """Initialize any state in this preconditioner.""" pass
[docs] def setUp(self, pc): """Setup method called by PETSc. Subclasses should probably not override this and instead implement :meth:`update` and :meth:`initialize`.""" if self.initialized: self.update(pc) else: self.initialize(pc) self.initialized = True
[docs] def view(self, pc, viewer=None): if viewer is None: return typ = viewer.getType() if typ != PETSc.Viewer.Type.ASCII: return viewer.printfASCII("Firedrake custom %s %s\n" % (self._asciiname, type(self).__name__))
[docs] @staticmethod def get_appctx(pc): from firedrake.dmhooks import get_appctx return get_appctx(pc.getDM()).appctx
[docs] @staticmethod def new_snes_ctx(pc, op, bcs, mat_type, fcp=None, options_prefix=None): """ Create a new SNES contex for nested preconditioning """ from firedrake.variational_solver import NonlinearVariationalProblem from firedrake.function import Function from firedrake.ufl_expr import action from firedrake.dmhooks import get_appctx from firedrake.solving_utils import _SNESContext dm = pc.getDM() old_appctx = get_appctx(dm).appctx u = Function(op.arguments()[-1].function_space()) F = action(op, u) nprob = NonlinearVariationalProblem(F, u, bcs=bcs, J=op, form_compiler_parameters=fcp) return _SNESContext(nprob, mat_type, mat_type, old_appctx, options_prefix=options_prefix)
[docs]class PCBase(PCSNESBase): _asciiname = "preconditioner" _objectname = "pc" needs_python_amat = False """Set this to True if the A matrix needs to be Python (matfree).""" needs_python_pmat = False """Set this to False if the P matrix needs to be Python (matfree). If the preconditioner also works with assembled matrices, then use False here. """
[docs] @abc.abstractmethod def apply(self, pc, X, Y): """Apply the preconditioner to X, putting the result in Y. Both X and Y are PETSc Vecs, Y is not guaranteed to be zero on entry. """ pass
[docs] @abc.abstractmethod def applyTranspose(self, pc, X, Y): """Apply the transpose of the preconditioner to X, putting the result in Y. Both X and Y are PETSc Vecs, Y is not guaranteed to be zero on entry. """ pass
[docs] def setUp(self, pc): A, P = pc.getOperators() Atype = A.getType() Ptype = P.getType() pcname = type(self).__module__ + "." + type(self).__name__ if self.needs_python_amat and Atype != PETSc.Mat.Type.PYTHON: raise ValueError("PC '%s' needs amat to have type python, but it is %s" % (pcname, Atype)) if self.needs_python_pmat and Ptype != PETSc.Mat.Type.PYTHON: raise ValueError("PC '%s' needs pmat to have type python, but it is %s" % (pcname, Ptype)) super().setUp(pc)
[docs]class SNESBase(PCSNESBase): _asciiname = "nonlinear solver" _objectname = "snes"