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Ginkgo Generated from branch based on main. Ginkgo version 1.11.0
A numerical linear algebra library targeting many-core architectures
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Ginkgo Generated from branch based on main. Ginkgo version 1.11.0
A numerical linear algebra library targeting many-core architectures
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FCG or the flexible conjugate gradient method is an iterative type Krylov subspace method which is suitable for symmetric positive definite methods. More...
#include <ginkgo/core/solver/fcg.hpp>
Classes | |
| struct | parameters_type |
| class | Factory |
Public Types | |
| using | value_type = ValueType |
| using | transposed_type = Fcg<ValueType> |
| Public Types inherited from gko::EnablePolymorphicAssignment< Fcg< default_precision > > | |
| using | result_type |
Public Member Functions | |
| std::unique_ptr< LinOp > | transpose () const override |
| Returns a LinOp representing the transpose of the Transposable object. | |
| std::unique_ptr< LinOp > | conj_transpose () const override |
| Returns a LinOp representing the conjugate transpose of the Transposable object. | |
| bool | apply_uses_initial_guess () const override |
| Return true as iterative solvers use the data in x as an initial guess. | |
| const parameters_type & | get_parameters () const |
| Public Member Functions inherited from gko::EnableLinOp< Fcg< default_precision > > | |
| const Fcg< default_precision > * | apply (ptr_param< const LinOp > b, ptr_param< LinOp > x) const |
| Public Member Functions inherited from gko::EnablePolymorphicAssignment< Fcg< default_precision > > | |
| void | convert_to (result_type *result) const override |
| void | move_to (result_type *result) override |
| Public Member Functions inherited from gko::solver::EnableSolverBase< Fcg< default_precision > > | |
| EnableSolverBase & | operator= (const EnableSolverBase &other) |
| Creates a shallow copy of the provided system matrix, clones it onto this executor if executors don't match. | |
| int | get_num_workspace_ops () const override |
| std::vector< std::string > | get_workspace_op_names () const override |
| std::vector< int > | get_workspace_scalars () const override |
| Returns the IDs of all scalars (workspace vectors with system dimension-independent size, usually 1 x num_rhs). | |
| std::vector< int > | get_workspace_vectors () const override |
| Returns the IDs of all vectors (workspace vectors with system dimension-dependent size, usually system_matrix_size x num_rhs). | |
| Public Member Functions inherited from gko::solver::SolverBase< LinOp > | |
| std::shared_ptr< const LinOp > | get_system_matrix () const |
| Returns the system matrix, with its concrete type, used by the solver. | |
| Public Member Functions inherited from gko::solver::EnableIterativeBase< Fcg< default_precision > > | |
| EnableIterativeBase & | operator= (const EnableIterativeBase &other) |
| Creates a shallow copy of the provided stopping criterion, clones it onto this executor if executors don't match. | |
| void | set_stop_criterion_factory (std::shared_ptr< const stop::CriterionFactory > new_stop_factory) override |
| Sets the stopping criterion of the solver. | |
| Public Member Functions inherited from gko::solver::IterativeBase | |
| std::shared_ptr< const stop::CriterionFactory > | get_stop_criterion_factory () const |
| Gets the stopping criterion factory of the solver. | |
| Public Member Functions inherited from gko::solver::EnablePreconditionable< Fcg< default_precision > > | |
| void | set_preconditioner (std::shared_ptr< const LinOp > new_precond) override |
| Sets the preconditioner operator used by the Preconditionable. | |
| EnablePreconditionable & | operator= (const EnablePreconditionable &other) |
| Creates a shallow copy of the provided preconditioner, clones it onto this executor if executors don't match. | |
| Public Member Functions inherited from gko::Preconditionable | |
| virtual std::shared_ptr< const LinOp > | get_preconditioner () const |
| Returns the preconditioner operator used by the Preconditionable. | |
Static Public Member Functions | |
| static auto | build () -> decltype(Factory::create()) |
| static parameters_type | parse (const config::pnode &config, const config::registry &context, const config::type_descriptor &td_for_child=config::make_type_descriptor< ValueType >()) |
| Create the parameters from the property_tree. | |
Friends | |
| class | EnableLinOp< Fcg > |
| class | EnablePolymorphicObject< Fcg, LinOp > |
FCG or the flexible conjugate gradient method is an iterative type Krylov subspace method which is suitable for symmetric positive definite methods.
Though this method performs very well for symmetric positive definite matrices, it is in general not suitable for general matrices.
In contrast to the standard CG based on the Polack-Ribiere formula, the flexible CG uses the Fletcher-Reeves formula for creating the orthonormal vectors spanning the Krylov subspace. This increases the computational cost of every Krylov solver iteration but allows for non-constant preconditioners.
The implementation in Ginkgo makes use of the merged kernel to make the best use of data locality. The inner operations in one iteration of FCG are merged into 2 separate steps.
| ValueType | precision of matrix elements |
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inlineoverride |
Return true as iterative solvers use the data in x as an initial guess.
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overridevirtual |
Returns a LinOp representing the conjugate transpose of the Transposable object.
Implements gko::Transposable.
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static |
Create the parameters from the property_tree.
Because this is directly tied to the specific type, the value/index type settings within config are ignored and type_descriptor is only used for children configs.
| config | the property tree for setting |
| context | the registry |
| td_for_child | the type descriptor for children configs. The default uses the value type of this class. |
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overridevirtual |
Returns a LinOp representing the transpose of the Transposable object.
Implements gko::Transposable.
1.15.0