How to use the pyamg.rootnode_solver function in pyamg
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romeric / florence / Florence / Solver / LinearSolver.py View on Github 
A = A.tocsr()
t_solve = time()
if self.iterative_solver_tolerance > 1e-9:
self.iterative_solver_tolerance = 1e-10
# AMG METHOD
amg_func = None
if self.preconditioner_type=="smoothed_aggregation":
# THIS IS TYPICALLY FASTER BUT THE TOLERANCE NEED TO BE SMALLER, TYPICALLY 1e-10
amg_func = smoothed_aggregation_solver
elif self.preconditioner_type == "ruge_stuben":
amg_func = ruge_stuben_solver
elif self.preconditioner_type == "rootnode":
amg_func = rootnode_solver
else:
amg_func = rootnode_solver
ml = amg_func(A)
# ml = amg_func(A, smooth=('energy', {'degree':2}), strength='evolution' )
# ml = amg_func(A, max_levels=3, diagonal_dominance=True)
# ml = amg_func(A, coarse_solver=spsolve)
# ml = amg_func(A, coarse_solver='cholesky')
if self.solver_context_manager is None:
# M = ml.aspreconditioner(cycle='V')
M = ml.aspreconditioner()
if self.reuse_factorisation:
self.solver_context_manager = M
else:
M = self.solver_context_managert_solve = time()
if self.iterative_solver_tolerance > 1e-9:
self.iterative_solver_tolerance = 1e-10
# AMG METHOD
amg_func = None
if self.preconditioner_type=="smoothed_aggregation":
# THIS IS TYPICALLY FASTER BUT THE TOLERANCE NEED TO BE SMALLER, TYPICALLY 1e-10
amg_func = smoothed_aggregation_solver
elif self.preconditioner_type == "ruge_stuben":
amg_func = ruge_stuben_solver
elif self.preconditioner_type == "rootnode":
amg_func = rootnode_solver
else:
amg_func = rootnode_solver
ml = amg_func(A)
# ml = amg_func(A, smooth=('energy', {'degree':2}), strength='evolution' )
# ml = amg_func(A, max_levels=3, diagonal_dominance=True)
# ml = amg_func(A, coarse_solver=spsolve)
# ml = amg_func(A, coarse_solver='cholesky')
if self.solver_context_manager is None:
# M = ml.aspreconditioner(cycle='V')
M = ml.aspreconditioner()
if self.reuse_factorisation:
self.solver_context_manager = M
else:
M = self.solver_context_manager
# EXPLICIT CALL TO KYROLOV SOLVERS WITH AMG PRECONDITIONERpyamg
PyAMG: Algebraic Multigrid Solvers in Python
