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gcr.hpp
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32
33#ifndef GKO_PUBLIC_CORE_SOLVER_GCR_HPP_
34#define GKO_PUBLIC_CORE_SOLVER_GCR_HPP_
35
36
37#include <vector>
38
39
40#include <ginkgo/core/base/array.hpp>
41#include <ginkgo/core/base/exception_helpers.hpp>
42#include <ginkgo/core/base/lin_op.hpp>
43#include <ginkgo/core/base/math.hpp>
44#include <ginkgo/core/base/types.hpp>
45#include <ginkgo/core/log/logger.hpp>
46#include <ginkgo/core/matrix/dense.hpp>
47#include <ginkgo/core/matrix/identity.hpp>
48#include <ginkgo/core/solver/solver_base.hpp>
49#include <ginkgo/core/stop/combined.hpp>
50#include <ginkgo/core/stop/criterion.hpp>
51
52
53namespace gko {
54namespace solver {
55
56
57constexpr size_type gcr_default_krylov_dim = 100u;
58
59
74template <typename ValueType = default_precision>
75class Gcr
76 : public EnableLinOp<Gcr<ValueType>>,
77 public EnablePreconditionedIterativeSolver<ValueType, Gcr<ValueType>>,
78 public Transposable {
79 friend class EnableLinOp<Gcr>;
80 friend class EnablePolymorphicObject<Gcr, LinOp>;
81
82public:
83 using value_type = ValueType;
85
86 std::unique_ptr<LinOp> transpose() const override;
87
88 std::unique_ptr<LinOp> conj_transpose() const override;
89
95 bool apply_uses_initial_guess() const override { return true; }
96
102 size_type get_krylov_dim() const { return parameters_.krylov_dim; }
103
110
111 class Factory;
112
121
122protected:
123 void apply_impl(const LinOp* b, LinOp* x) const override;
124
125 template <typename VectorType>
126 void apply_dense_impl(const VectorType* b, VectorType* x) const;
127
128 void apply_impl(const LinOp* alpha, const LinOp* b, const LinOp* beta,
129 LinOp* x) const override;
130
131 explicit Gcr(std::shared_ptr<const Executor> exec)
132 : EnableLinOp<Gcr>(std::move(exec))
133 {}
134
135 explicit Gcr(const Factory* factory,
136 std::shared_ptr<const LinOp> system_matrix)
137 : EnableLinOp<Gcr>(factory->get_executor(),
138 gko::transpose(system_matrix->get_size())),
139 EnablePreconditionedIterativeSolver<ValueType, Gcr<ValueType>>{
140 std::move(system_matrix), factory->get_parameters()},
141 parameters_{factory->get_parameters()}
142 {
143 if (!parameters_.krylov_dim) {
144 parameters_.krylov_dim = gcr_default_krylov_dim;
145 }
146 }
147};
148
149
150template <typename ValueType>
151struct workspace_traits<Gcr<ValueType>> {
152 using Solver = Gcr<ValueType>;
153 // number of vectors used by this workspace
154 static int num_vectors(const Solver&);
155 // number of arrays used by this workspace
156 static int num_arrays(const Solver&);
157 // array containing the num_vectors names for the workspace vectors
158 static std::vector<std::string> op_names(const Solver&);
159 // array containing the num_arrays names for the workspace vectors
160 static std::vector<std::string> array_names(const Solver&);
161 // array containing all varying scalar vectors (independent of problem size)
162 static std::vector<int> scalars(const Solver&);
163 // array containing all varying vectors (dependent on problem size)
164 static std::vector<int> vectors(const Solver&);
165
166 // residual vector
167 constexpr static int residual = 0;
168 // preconditioned vector
169 constexpr static int precon_residual = 1;
170 // A* preconditioned vector
171 constexpr static int A_precon_residual = 2;
172 // krylov bases (p in the algorithm)
173 constexpr static int krylov_bases_p = 3;
174 // mapped krylov bases (Ap in the algorithm)
175 constexpr static int mapped_krylov_bases_Ap = 4;
176 // tmp rAp parameter (r dot Ap in the algorithm)
177 constexpr static int tmp_rAp = 5;
178 // tmp minus beta parameter (-beta in the algorithm)
179 constexpr static int tmp_minus_beta = 6;
180 // array of norms of Ap
181 constexpr static int Ap_norms = 7;
182 // residual norm scalar
183 constexpr static int residual_norm = 8;
184 // constant 1.0 scalar
185 constexpr static int one = 9;
186 // constant -1.0 scalar
187 constexpr static int minus_one = 10;
188
189 // stopping status array
190 constexpr static int stop = 0;
191 // reduction tmp array
192 constexpr static int tmp = 1;
193 // final iteration number array
194 constexpr static int final_iter_nums = 2;
195};
196
197
198} // namespace solver
199} // namespace gko
200
201
202#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:908
This mixin inherits from (a subclass of) PolymorphicObject and provides a base implementation of a ne...
Definition polymorphic_object.hpp:691
Definition lin_op.hpp:146
std::shared_ptr< const Executor > get_executor() const noexcept
Returns the Executor of the object.
Definition polymorphic_object.hpp:263
Linear operators which support transposition should implement the Transposable interface.
Definition lin_op.hpp:462
A LinOp implementing this interface stores a system matrix and stopping criterion factory.
Definition solver_base.hpp:816
Definition gcr.hpp:119
GCR or the generalized conjugate residual method is an iterative type Krylov subspace method similar ...
Definition gcr.hpp:78
size_type get_krylov_dim() const
Gets the Krylov dimension of the solver.
Definition gcr.hpp:102
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:109
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:95
#define GKO_FACTORY_PARAMETER_SCALAR(_name, _default)
Creates a scalar factory parameter in the factory parameters structure.
Definition abstract_factory.hpp:473
#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:422
#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:1046
The Ginkgo namespace.
Definition abstract_factory.hpp:48
constexpr T one()
Returns the multiplicative identity for T.
Definition math.hpp:803
std::size_t size_type
Integral type used for allocation quantities.
Definition types.hpp:120
Definition gcr.hpp:115
size_type krylov_dim
Krylov subspace dimension/restart value.
Definition gcr.hpp:117
Traits class providing information on the type and location of workspace vectors inside a solver.
Definition solver_base.hpp:267