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A numerical linear algebra library targeting many-core architectures
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cg.hpp
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32
33#ifndef GKO_PUBLIC_CORE_SOLVER_CG_HPP_
34#define GKO_PUBLIC_CORE_SOLVER_CG_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
73template <typename ValueType = default_precision>
74class Cg : public EnableLinOp<Cg<ValueType>>,
75 public EnablePreconditionedIterativeSolver<ValueType, Cg<ValueType>>,
76 public Transposable {
77 friend class EnableLinOp<Cg>;
78 friend class EnablePolymorphicObject<Cg, LinOp>;
79
80public:
81 using value_type = ValueType;
83
84 std::unique_ptr<LinOp> transpose() const override;
85
86 std::unique_ptr<LinOp> conj_transpose() const override;
87
93 bool apply_uses_initial_guess() const override { return true; }
94
95 class Factory;
96
100
103
104protected:
105 void apply_impl(const LinOp* b, LinOp* x) const override;
106
107 template <typename VectorType>
108 void apply_dense_impl(const VectorType* b, VectorType* x) const;
109
110 void apply_impl(const LinOp* alpha, const LinOp* b, const LinOp* beta,
111 LinOp* x) const override;
112
113 explicit Cg(std::shared_ptr<const Executor> exec)
114 : EnableLinOp<Cg>(std::move(exec))
115 {}
116
117 explicit Cg(const Factory* factory,
118 std::shared_ptr<const LinOp> system_matrix)
119 : EnableLinOp<Cg>(factory->get_executor(),
120 gko::transpose(system_matrix->get_size())),
121 EnablePreconditionedIterativeSolver<ValueType, Cg<ValueType>>{
122 std::move(system_matrix), factory->get_parameters()},
123 parameters_{factory->get_parameters()}
124 {}
125};
126
127
128template <typename ValueType>
129struct workspace_traits<Cg<ValueType>> {
130 using Solver = Cg<ValueType>;
131 // number of vectors used by this workspace
132 static int num_vectors(const Solver&);
133 // number of arrays used by this workspace
134 static int num_arrays(const Solver&);
135 // array containing the num_vectors names for the workspace vectors
136 static std::vector<std::string> op_names(const Solver&);
137 // array containing the num_arrays names for the workspace vectors
138 static std::vector<std::string> array_names(const Solver&);
139 // array containing all varying scalar vectors (independent of problem size)
140 static std::vector<int> scalars(const Solver&);
141 // array containing all varying vectors (dependent on problem size)
142 static std::vector<int> vectors(const Solver&);
143
144 // residual vector
145 constexpr static int r = 0;
146 // preconditioned residual vector
147 constexpr static int z = 1;
148 // p vector
149 constexpr static int p = 2;
150 // q vector
151 constexpr static int q = 3;
152 // alpha scalar
153 constexpr static int alpha = 4;
154 // beta scalar
155 constexpr static int beta = 5;
156 // previous rho scalar
157 constexpr static int prev_rho = 6;
158 // current rho scalar
159 constexpr static int rho = 7;
160 // constant 1.0 scalar
161 constexpr static int one = 8;
162 // constant -1.0 scalar
163 constexpr static int minus_one = 9;
164
165 // stopping status array
166 constexpr static int stop = 0;
167 // reduction tmp array
168 constexpr static int tmp = 1;
169};
170
171
172} // namespace solver
173} // namespace gko
174
175
176#endif // GKO_PUBLIC_CORE_SOLVER_CG_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
Definition cg.hpp:101
CG or the conjugate gradient method is an iterative type Krylov subspace method which is suitable for...
Definition cg.hpp:76
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.
bool apply_uses_initial_guess() const override
Return true as iterative solvers use the data in x as an initial guess.
Definition cg.hpp:93
A LinOp implementing this interface stores a system matrix and stopping criterion factory.
Definition solver_base.hpp:816
#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
Traits class providing information on the type and location of workspace vectors inside a solver.
Definition solver_base.hpp:267