Ginkgo Generated from branch based on main. Ginkgo version 1.9.0
A numerical linear algebra library targeting many-core architectures
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fcg.hpp
1// SPDX-FileCopyrightText: 2017 - 2024 The Ginkgo authors
2//
3// SPDX-License-Identifier: BSD-3-Clause
4
5#ifndef GKO_PUBLIC_CORE_SOLVER_FCG_HPP_
6#define GKO_PUBLIC_CORE_SOLVER_FCG_HPP_
7
8
9#include <vector>
10
11#include <ginkgo/core/base/array.hpp>
12#include <ginkgo/core/base/exception_helpers.hpp>
13#include <ginkgo/core/base/lin_op.hpp>
14#include <ginkgo/core/base/math.hpp>
15#include <ginkgo/core/base/types.hpp>
16#include <ginkgo/core/config/config.hpp>
17#include <ginkgo/core/config/registry.hpp>
18#include <ginkgo/core/log/logger.hpp>
19#include <ginkgo/core/matrix/dense.hpp>
20#include <ginkgo/core/matrix/identity.hpp>
21#include <ginkgo/core/solver/solver_base.hpp>
22#include <ginkgo/core/stop/combined.hpp>
23#include <ginkgo/core/stop/criterion.hpp>
24
25
26namespace gko {
27namespace solver {
28
29
51template <typename ValueType = default_precision>
52class Fcg
53 : public EnableLinOp<Fcg<ValueType>>,
54 public EnablePreconditionedIterativeSolver<ValueType, Fcg<ValueType>>,
55 public Transposable {
56 friend class EnableLinOp<Fcg>;
57 friend class EnablePolymorphicObject<Fcg, LinOp>;
58
59public:
60 using value_type = ValueType;
62
63 std::unique_ptr<LinOp> transpose() const override;
64
65 std::unique_ptr<LinOp> conj_transpose() const override;
66
72 bool apply_uses_initial_guess() const override { return true; }
73
74 class Factory;
75
79
82
96 static parameters_type parse(const config::pnode& config,
97 const config::registry& context,
98 const config::type_descriptor& td_for_child =
99 config::make_type_descriptor<ValueType>());
100
101protected:
102 void apply_impl(const LinOp* b, LinOp* x) const override;
103
104 template <typename VectorType>
105 void apply_dense_impl(const VectorType* b, VectorType* x) const;
106
107 void apply_impl(const LinOp* alpha, const LinOp* b, const LinOp* beta,
108 LinOp* x) const override;
109
110 explicit Fcg(std::shared_ptr<const Executor> exec)
111 : EnableLinOp<Fcg>(std::move(exec))
112 {}
113
114 explicit Fcg(const Factory* factory,
115 std::shared_ptr<const LinOp> system_matrix)
116 : EnableLinOp<Fcg>(factory->get_executor(),
117 gko::transpose(system_matrix->get_size())),
118 EnablePreconditionedIterativeSolver<ValueType, Fcg<ValueType>>{
119 std::move(system_matrix), factory->get_parameters()},
120 parameters_{factory->get_parameters()}
121 {}
122};
123
124
125template <typename ValueType>
126struct workspace_traits<Fcg<ValueType>> {
127 using Solver = Fcg<ValueType>;
128 // number of vectors used by this workspace
129 static int num_vectors(const Solver&);
130 // number of arrays used by this workspace
131 static int num_arrays(const Solver&);
132 // array containing the num_vectors names for the workspace vectors
133 static std::vector<std::string> op_names(const Solver&);
134 // array containing the num_arrays names for the workspace vectors
135 static std::vector<std::string> array_names(const Solver&);
136 // array containing all varying scalar vectors (independent of problem size)
137 static std::vector<int> scalars(const Solver&);
138 // array containing all varying vectors (dependent on problem size)
139 static std::vector<int> vectors(const Solver&);
140
141 // residual vector
142 constexpr static int r = 0;
143 // preconditioned residual vector
144 constexpr static int z = 1;
145 // p vector
146 constexpr static int p = 2;
147 // q vector
148 constexpr static int q = 3;
149 // t vector
150 constexpr static int t = 4;
151 // beta scalar
152 constexpr static int beta = 5;
153 // previous rho scalar
154 constexpr static int prev_rho = 6;
155 // current rho scalar
156 constexpr static int rho = 7;
157 // current rho_t scalar
158 constexpr static int rho_t = 8;
159 // constant 1.0 scalar
160 constexpr static int one = 9;
161 // constant -1.0 scalar
162 constexpr static int minus_one = 10;
163
164 // stopping status array
165 constexpr static int stop = 0;
166 // reduction tmp array
167 constexpr static int tmp = 1;
168};
169
170
171} // namespace solver
172} // namespace gko
173
174
175#endif // GKO_PUBLIC_CORE_SOLVER_FCG_HPP_
The EnableLinOp mixin can be used to provide sensible default implementations of the majority of the ...
Definition lin_op.hpp:879
This mixin inherits from (a subclass of) PolymorphicObject and provides a base implementation of a ne...
Definition polymorphic_object.hpp:662
Definition lin_op.hpp:117
const dim< 2 > & get_size() const noexcept
Returns the size of the operator.
Definition lin_op.hpp:210
std::shared_ptr< const Executor > get_executor() const noexcept
Returns the Executor of the object.
Definition polymorphic_object.hpp:234
Linear operators which support transposition should implement the Transposable interface.
Definition lin_op.hpp:433
pnode describes a tree of properties.
Definition property_tree.hpp:28
This class stores additional context for creating Ginkgo objects from configuration files.
Definition registry.hpp:167
This class describes the value and index types to be used when building a Ginkgo type from a configur...
Definition type_descriptor.hpp:39
A LinOp implementing this interface stores a system matrix and stopping criterion factory.
Definition solver_base.hpp:787
Definition fcg.hpp:80
FCG or the flexible conjugate gradient method is an iterative type Krylov subspace method which is su...
Definition fcg.hpp:55
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.
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.
bool apply_uses_initial_guess() const override
Return true as iterative solvers use the data in x as an initial guess.
Definition fcg.hpp:72
#define GKO_ENABLE_BUILD_METHOD(_factory_name)
Defines a build method for the factory, simplifying its construction by removing the repetitive typin...
Definition abstract_factory.hpp:394
#define GKO_ENABLE_LIN_OP_FACTORY(_lin_op, _parameters_name, _factory_name)
This macro will generate a default implementation of a LinOpFactory for the LinOp subclass it is defi...
Definition lin_op.hpp:1017
The Ginkgo namespace.
Definition abstract_factory.hpp:20
constexpr T one()
Returns the multiplicative identity for T.
Definition math.hpp:630
STL namespace.
Traits class providing information on the type and location of workspace vectors inside a solver.
Definition solver_base.hpp:238