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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cgs.hpp
1// SPDX-FileCopyrightText: 2017 - 2024 The Ginkgo authors
2//
3// SPDX-License-Identifier: BSD-3-Clause
4
5#ifndef GKO_PUBLIC_CORE_SOLVER_CGS_HPP_
6#define GKO_PUBLIC_CORE_SOLVER_CGS_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
43template <typename ValueType = default_precision>
44class Cgs
45 : public EnableLinOp<Cgs<ValueType>>,
46 public EnablePreconditionedIterativeSolver<ValueType, Cgs<ValueType>>,
47 public Transposable {
48 friend class EnableLinOp<Cgs>;
49 friend class EnablePolymorphicObject<Cgs, LinOp>;
50
51public:
52 using value_type = ValueType;
54
55 std::unique_ptr<LinOp> transpose() const override;
56
57 std::unique_ptr<LinOp> conj_transpose() const override;
58
64 bool apply_uses_initial_guess() const override { return true; }
65
66 class Factory;
67
71
74
88 static parameters_type parse(const config::pnode& config,
89 const config::registry& context,
90 const config::type_descriptor& td_for_child =
91 config::make_type_descriptor<ValueType>());
92
93protected:
94 void apply_impl(const LinOp* b, LinOp* x) const override;
95
96 template <typename VectorType>
97 void apply_dense_impl(const VectorType* b, VectorType* x) const;
98
99 void apply_impl(const LinOp* alpha, const LinOp* b, const LinOp* beta,
100 LinOp* x) const override;
101
102 explicit Cgs(std::shared_ptr<const Executor> exec)
103 : EnableLinOp<Cgs>(std::move(exec))
104 {}
105
106 explicit Cgs(const Factory* factory,
107 std::shared_ptr<const LinOp> system_matrix)
108 : EnableLinOp<Cgs>(factory->get_executor(),
109 gko::transpose(system_matrix->get_size())),
110 EnablePreconditionedIterativeSolver<ValueType, Cgs<ValueType>>{
111 std::move(system_matrix), factory->get_parameters()},
112 parameters_{factory->get_parameters()}
113 {}
114};
115
116
117template <typename ValueType>
118struct workspace_traits<Cgs<ValueType>> {
119 using Solver = Cgs<ValueType>;
120 // number of vectors used by this workspace
121 static int num_vectors(const Solver&);
122 // number of arrays used by this workspace
123 static int num_arrays(const Solver&);
124 // array containing the num_vectors names for the workspace vectors
125 static std::vector<std::string> op_names(const Solver&);
126 // array containing the num_arrays names for the workspace vectors
127 static std::vector<std::string> array_names(const Solver&);
128 // array containing all varying scalar vectors (independent of problem size)
129 static std::vector<int> scalars(const Solver&);
130 // array containing all varying vectors (dependent on problem size)
131 static std::vector<int> vectors(const Solver&);
132
133 // residual vector
134 constexpr static int r = 0;
135 // r tilde vector
136 constexpr static int r_tld = 1;
137 // p vector
138 constexpr static int p = 2;
139 // q vector
140 constexpr static int q = 3;
141 // u vector
142 constexpr static int u = 4;
143 // u hat vector
144 constexpr static int u_hat = 5;
145 // v hat vector
146 constexpr static int v_hat = 6;
147 // t vector
148 constexpr static int t = 7;
149 // alpha scalar
150 constexpr static int alpha = 8;
151 // beta scalar
152 constexpr static int beta = 9;
153 // beta scalar
154 constexpr static int gamma = 10;
155 // previous rho scalar
156 constexpr static int prev_rho = 11;
157 // current rho scalar
158 constexpr static int rho = 12;
159 // constant 1.0 scalar
160 constexpr static int one = 13;
161 // constant -1.0 scalar
162 constexpr static int minus_one = 14;
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_CGS_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
Definition cgs.hpp:72
CGS or the conjugate gradient square method is an iterative type Krylov subspace method which is suit...
Definition cgs.hpp:47
bool apply_uses_initial_guess() const override
Return true as iterative solvers use the data in x as an initial guess.
Definition cgs.hpp:64
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.
std::unique_ptr< LinOp > transpose() const override
Returns a LinOp representing the transpose of the Transposable object.
A LinOp implementing this interface stores a system matrix and stopping criterion factory.
Definition solver_base.hpp:787
#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