def block_solve(block_A, block_x, block_b, linear_solver="default"):
assert isinstance(block_A, GenericBlockMatrix)
assert isinstance(block_x, GenericBlockVector)
assert isinstance(block_b, GenericBlockVector)
# Solve
solver = PETScLUSolver(linear_solver)
solver.solve(block_A, block_x, block_b)
# Keep subfunctions up to date
block_x.block_function().apply("to subfunctions")
def test_lu_cholesky():
"""Test that PETScLUSolver selects LU or Cholesky solver based on
symmetry of matrix operator.
"""
from petsc4py import PETSc
mesh = UnitSquareMesh(mpi_comm_world(), 12, 12)
V = FunctionSpace(mesh, "Lagrange", 1)
u, v = TrialFunction(V), TestFunction(V)
A = PETScMatrix(mesh.mpi_comm())
assemble(Constant(1.0)*u*v*dx, tensor=A)
# Check that solver type is LU
solver = PETScLUSolver(mesh.mpi_comm(), A, "petsc")
pc_type = solver.ksp().getPC().getType()
assert pc_type == "lu"
# Set symmetry flag
A.mat().setOption(PETSc.Mat.Option.SYMMETRIC, True)
# Check symmetry flags
symm = A.mat().isSymmetricKnown()
assert symm[0] == True
assert symm[1] == True
# Check that solver type is Cholesky since matrix has now been
# marked as symmetric
solver = PETScLUSolver(mesh.mpi_comm(), A, "petsc")
pc_type = solver.ksp().getPC().getType()
assert pc_type == "cholesky"
# Re-assemble, which resets symmetry flag
assemble(Constant(1.0)*u*v*dx, tensor=A)
solver = PETScLUSolver(mesh.mpi_comm(), A, "petsc")
pc_type = solver.ksp().getPC().getType()
assert pc_type == "lu"
def test_lu_cholesky():
"""Test that PETScLUSolver selects LU or Cholesky solver based on
symmetry of matrix operator.
"""
from petsc4py import PETSc
mesh = UnitSquareMesh(MPI.comm_world, 12, 12)
V = FunctionSpace(mesh, "Lagrange", 1)
u, v = TrialFunction(V), TestFunction(V)
A = PETScMatrix(mesh.mpi_comm())
assemble(Constant(1.0)*u*v*dx, tensor=A)
# Check that solver type is LU
solver = PETScLUSolver(mesh.mpi_comm(), A, "petsc")
pc_type = solver.ksp().getPC().getType()
assert pc_type == "lu"
# Set symmetry flag
A.mat().setOption(PETSc.Mat.Option.SYMMETRIC, True)
# Check symmetry flags
symm = A.mat().isSymmetricKnown()
assert symm[0] == True
assert symm[1] == True
# Check that solver type is Cholesky since matrix has now been
# marked as symmetric
solver = PETScLUSolver(mesh.mpi_comm(), A, "petsc")
pc_type = solver.ksp().getPC().getType()
assert pc_type == "cholesky"
# Re-assemble, which resets symmetry flag
assemble(Constant(1.0)*u*v*dx, tensor=A)
solver = PETScLUSolver(mesh.mpi_comm(), A, "petsc")
pc_type = solver.ksp().getPC().getType()
assert pc_type == "lu"
def solve(self):
solver = PETScLUSolver(self._linear_solver)
solver.solve(self.lhs, self.solution.vector(), self.rhs)
if self.monitor is not None:
self.monitor(self.solution)
def solve(self):
solver = PETScLUSolver(self._linear_solver)
solver.solve(self.lhs, self.solution.vector(), self.rhs)
return self.solution