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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gcr.hpp
1// SPDX-FileCopyrightText: 2017 - 2024 The Ginkgo authors
2//
3// SPDX-License-Identifier: BSD-3-Clause
4
5#ifndef GKO_PUBLIC_CORE_SOLVER_GCR_HPP_
6#define GKO_PUBLIC_CORE_SOLVER_GCR_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
29constexpr size_type gcr_default_krylov_dim = 100u;
30
31
46template <typename ValueType = default_precision>
47class Gcr
48 : public EnableLinOp<Gcr<ValueType>>,
49 public EnablePreconditionedIterativeSolver<ValueType, Gcr<ValueType>>,
50 public Transposable {
51 friend class EnableLinOp<Gcr>;
52 friend class EnablePolymorphicObject<Gcr, LinOp>;
53
54public:
55 using value_type = ValueType;
57
58 std::unique_ptr<LinOp> transpose() const override;
59
60 std::unique_ptr<LinOp> conj_transpose() const override;
61
67 bool apply_uses_initial_guess() const override { return true; }
68
74 size_type get_krylov_dim() const { return parameters_.krylov_dim; }
75
82
83 class Factory;
84
93
94protected:
95 void apply_impl(const LinOp* b, LinOp* x) const override;
96
97 template <typename VectorType>
98 void apply_dense_impl(const VectorType* b, VectorType* x) const;
99
100 void apply_impl(const LinOp* alpha, const LinOp* b, const LinOp* beta,
101 LinOp* x) const override;
102
103 explicit Gcr(std::shared_ptr<const Executor> exec)
104 : EnableLinOp<Gcr>(std::move(exec))
105 {}
106
107 explicit Gcr(const Factory* factory,
108 std::shared_ptr<const LinOp> system_matrix)
109 : EnableLinOp<Gcr>(factory->get_executor(),
110 gko::transpose(system_matrix->get_size())),
111 EnablePreconditionedIterativeSolver<ValueType, Gcr<ValueType>>{
112 std::move(system_matrix), factory->get_parameters()},
113 parameters_{factory->get_parameters()}
114 {
115 if (!parameters_.krylov_dim) {
116 parameters_.krylov_dim = gcr_default_krylov_dim;
117 }
118 }
119};
120
121
122template <typename ValueType>
123struct workspace_traits<Gcr<ValueType>> {
124 using Solver = Gcr<ValueType>;
125 // number of vectors used by this workspace
126 static int num_vectors(const Solver&);
127 // number of arrays used by this workspace
128 static int num_arrays(const Solver&);
129 // array containing the num_vectors names for the workspace vectors
130 static std::vector<std::string> op_names(const Solver&);
131 // array containing the num_arrays names for the workspace vectors
132 static std::vector<std::string> array_names(const Solver&);
133 // array containing all varying scalar vectors (independent of problem size)
134 static std::vector<int> scalars(const Solver&);
135 // array containing all varying vectors (dependent on problem size)
136 static std::vector<int> vectors(const Solver&);
137
138 // residual vector
139 constexpr static int residual = 0;
140 // preconditioned vector
141 constexpr static int precon_residual = 1;
142 // A* preconditioned vector
143 constexpr static int A_precon_residual = 2;
144 // krylov bases (p in the algorithm)
145 constexpr static int krylov_bases_p = 3;
146 // mapped krylov bases (Ap in the algorithm)
147 constexpr static int mapped_krylov_bases_Ap = 4;
148 // tmp rAp parameter (r dot Ap in the algorithm)
149 constexpr static int tmp_rAp = 5;
150 // tmp minus beta parameter (-beta in the algorithm)
151 constexpr static int tmp_minus_beta = 6;
152 // array of norms of Ap
153 constexpr static int Ap_norms = 7;
154 // residual norm scalar
155 constexpr static int residual_norm = 8;
156 // constant 1.0 scalar
157 constexpr static int one = 9;
158 // constant -1.0 scalar
159 constexpr static int minus_one = 10;
160
161 // stopping status array
162 constexpr static int stop = 0;
163 // reduction tmp array
164 constexpr static int tmp = 1;
165 // final iteration number array
166 constexpr static int final_iter_nums = 2;
167};
168
169
170} // namespace solver
171} // namespace gko
172
173
174#endif // GKO_PUBLIC_CORE_SOLVER_GCR_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
A LinOp implementing this interface stores a system matrix and stopping criterion factory.
Definition solver_base.hpp:788
Definition gcr.hpp:91
GCR or the generalized conjugate residual method is an iterative type Krylov subspace method similar ...
Definition gcr.hpp:50
size_type get_krylov_dim() const
Gets the Krylov dimension of the solver.
Definition gcr.hpp:74
std::unique_ptr< LinOp > conj_transpose() const override
Returns a LinOp representing the conjugate transpose of the Transposable object.
void set_krylov_dim(size_type other)
Sets the Krylov dimension.
Definition gcr.hpp:81
std::unique_ptr< LinOp > transpose() const override
Returns a LinOp representing the 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.
Definition gcr.hpp:67
#define GKO_FACTORY_PARAMETER_SCALAR(_name, _default)
Creates a scalar factory parameter in the factory parameters structure.
Definition abstract_factory.hpp:445
#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
std::size_t size_type
Integral type used for allocation quantities.
Definition types.hpp:92
size_type krylov_dim
Krylov subspace dimension/restart value.
Definition gcr.hpp:89
Traits class providing information on the type and location of workspace vectors inside a solver.
Definition solver_base.hpp:239