Ginkgo Generated from develop branch based on develop. Ginkgo version 1.8.0
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
12#include <ginkgo/core/base/array.hpp>
13#include <ginkgo/core/base/exception_helpers.hpp>
14#include <ginkgo/core/base/lin_op.hpp>
15#include <ginkgo/core/base/math.hpp>
16#include <ginkgo/core/base/types.hpp>
17#include <ginkgo/core/log/logger.hpp>
18#include <ginkgo/core/matrix/dense.hpp>
19#include <ginkgo/core/matrix/identity.hpp>
20#include <ginkgo/core/solver/solver_base.hpp>
21#include <ginkgo/core/stop/combined.hpp>
22#include <ginkgo/core/stop/criterion.hpp>
23
24
25namespace gko {
26namespace solver {
27
28
42template <typename ValueType = default_precision>
43class Cgs
44 : public EnableLinOp<Cgs<ValueType>>,
45 public EnablePreconditionedIterativeSolver<ValueType, Cgs<ValueType>>,
46 public Transposable {
47 friend class EnableLinOp<Cgs>;
48 friend class EnablePolymorphicObject<Cgs, LinOp>;
49
50public:
51 using value_type = ValueType;
53
54 std::unique_ptr<LinOp> transpose() const override;
55
56 std::unique_ptr<LinOp> conj_transpose() const override;
57
63 bool apply_uses_initial_guess() const override { return true; }
64
65 class Factory;
66
70
73
74protected:
75 void apply_impl(const LinOp* b, LinOp* x) const override;
76
77 template <typename VectorType>
78 void apply_dense_impl(const VectorType* b, VectorType* x) const;
79
80 void apply_impl(const LinOp* alpha, const LinOp* b, const LinOp* beta,
81 LinOp* x) const override;
82
83 explicit Cgs(std::shared_ptr<const Executor> exec)
84 : EnableLinOp<Cgs>(std::move(exec))
85 {}
86
87 explicit Cgs(const Factory* factory,
88 std::shared_ptr<const LinOp> system_matrix)
89 : EnableLinOp<Cgs>(factory->get_executor(),
90 gko::transpose(system_matrix->get_size())),
91 EnablePreconditionedIterativeSolver<ValueType, Cgs<ValueType>>{
92 std::move(system_matrix), factory->get_parameters()},
93 parameters_{factory->get_parameters()}
94 {}
95};
96
97
98template <typename ValueType>
99struct workspace_traits<Cgs<ValueType>> {
100 using Solver = Cgs<ValueType>;
101 // number of vectors used by this workspace
102 static int num_vectors(const Solver&);
103 // number of arrays used by this workspace
104 static int num_arrays(const Solver&);
105 // array containing the num_vectors names for the workspace vectors
106 static std::vector<std::string> op_names(const Solver&);
107 // array containing the num_arrays names for the workspace vectors
108 static std::vector<std::string> array_names(const Solver&);
109 // array containing all varying scalar vectors (independent of problem size)
110 static std::vector<int> scalars(const Solver&);
111 // array containing all varying vectors (dependent on problem size)
112 static std::vector<int> vectors(const Solver&);
113
114 // residual vector
115 constexpr static int r = 0;
116 // r tilde vector
117 constexpr static int r_tld = 1;
118 // p vector
119 constexpr static int p = 2;
120 // q vector
121 constexpr static int q = 3;
122 // u vector
123 constexpr static int u = 4;
124 // u hat vector
125 constexpr static int u_hat = 5;
126 // v hat vector
127 constexpr static int v_hat = 6;
128 // t vector
129 constexpr static int t = 7;
130 // alpha scalar
131 constexpr static int alpha = 8;
132 // beta scalar
133 constexpr static int beta = 9;
134 // beta scalar
135 constexpr static int gamma = 10;
136 // previous rho scalar
137 constexpr static int prev_rho = 11;
138 // current rho scalar
139 constexpr static int rho = 12;
140 // constant 1.0 scalar
141 constexpr static int one = 13;
142 // constant -1.0 scalar
143 constexpr static int minus_one = 14;
144
145 // stopping status array
146 constexpr static int stop = 0;
147 // reduction tmp array
148 constexpr static int tmp = 1;
149};
150
151
152} // namespace solver
153} // namespace gko
154
155
156#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:880
This mixin inherits from (a subclass of) PolymorphicObject and provides a base implementation of a ne...
Definition polymorphic_object.hpp:663
Definition lin_op.hpp:118
std::shared_ptr< const Executor > get_executor() const noexcept
Returns the Executor of the object.
Definition polymorphic_object.hpp:235
Linear operators which support transposition should implement the Transposable interface.
Definition lin_op.hpp:434
Definition cgs.hpp:71
CGS or the conjugate gradient square method is an iterative type Krylov subspace method which is suit...
Definition cgs.hpp:46
bool apply_uses_initial_guess() const override
Return true as iterative solvers use the data in x as an initial guess.
Definition cgs.hpp:63
std::unique_ptr< LinOp > conj_transpose() const override
Returns a LinOp representing the conjugate transpose of the Transposable object.
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:788
#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:1018
The Ginkgo namespace.
Definition abstract_factory.hpp:20
constexpr T one()
Returns the multiplicative identity for T.
Definition math.hpp:775
Traits class providing information on the type and location of workspace vectors inside a solver.
Definition solver_base.hpp:239