Writtin documentation for BICGStab method. (48503fb8) · Commits · TNL / tnl-dev

src/TNL/Solvers/Linear/BICGStab.h

+84 −23

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		@@ -10,30 +10,91 @@

		#pragma once

		#include "LinearSolver.h"
		#include <TNL/Solvers/Linear/LinearSolver.h>

		namespace TNL {
		namespace Solvers {
		namespace Linear {

		/**
		* \brief Iterative solver of linear systems based on the biconjugate gradient stabilized (BICGStab) method.
		*
		* This solver can be used for nonsymmetric linear systems.
		*
		* See [Wikipedia](https://en.wikipedia.org/wiki/Biconjugate_gradient_stabilized_method) for more details.
		*
		* \tparam Matrix is type of matrix describing the linear system.
		*/
		template< typename Matrix >
		class BICGStab
		: public LinearSolver< Matrix >
		{
		using Base = LinearSolver< Matrix >;
		using VectorType = typename Traits< Matrix >::VectorType;

		public:

		/**
		* \brief Floating point type used for computations.
		*/
		using RealType = typename Base::RealType;

		/**
		* \brief Device where the solver will run on and auxillary data will alloacted on.
		*
		* See \ref Devices::Host or \ref Devices::Cuda.
		*/
		using DeviceType = typename Base::DeviceType;

		/**
		* \brief Type for indexing.
		*/
		using IndexType = typename Base::IndexType;

		/**
		* \brief Type for vector view.
		*/
		using VectorViewType = typename Base::VectorViewType;

		/**
		* \brief Type for constant vector view.
		*/
		using ConstVectorViewType = typename Base::ConstVectorViewType;

		/**
		* \brief This is method defines configuration entries for setup of the linear iterative solver.
		*
		* In addition to config entries defined by \ref IterativeSolver::configSetup, this method
		* defines the following:
		*
		* \e bicgstab-exact-residue - says whether the BiCGstab should compute the exact residue in
		* each step (true) or to use a cheap approximation (false).
		*
		* \param config contains description of configuration parameters.
		* \param prefix is a prefix of particular configuration entries.
		*/
		static void configSetup( Config::ConfigDescription& config,
		const String& prefix = "" );

		/**
		* \brief Method for setup of the linear iterative solver based on configuration parameters.
		*
		* \param parameters contains values of the define configuration entries.
		* \param prefix is a prefix of particular configuration entries.
		*/
		bool setup( const Config::ParameterContainer& parameters,
		const String& prefix = "" ) override;

		/**
		* \brief Method for solving of a linear system.
		*
		* See \ref LinearSolver::solve for more details.
		*
		* \param b vector with the right-hand side of the linear system.
		* \param x vector for the solution of the linear system.
		* \return true if the solver converged.
		* \return false if the solver did not converge.
		*/
		bool solve( ConstVectorViewType b, VectorViewType x ) override;

		protected:
		@@ -45,11 +106,11 @@ protected:

		bool exact_residue = false;

		typename Traits< Matrix >::VectorType r, r_ast, p, s, Ap, As, M_tmp;
		VectorType r, r_ast, p, s, Ap, As, M_tmp;
		};

		} // namespace Linear
		} // namespace Solvers
		} // namespace TNL

		#include "BICGStab.hpp"
		#include <TNL/Solvers/Linear/BICGStab.hpp>