Line data    Source code

       1             : // The libMesh Finite Element Library.
       2             : // Copyright (C) 2002-2025 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner
       3             : 
       4             : // This library is free software; you can redistribute it and/or
       5             : // modify it under the terms of the GNU Lesser General Public
       6             : // License as published by the Free Software Foundation; either
       7             : // version 2.1 of the License, or (at your option) any later version.
       8             : 
       9             : // This library is distributed in the hope that it will be useful,
      10             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      11             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12             : // Lesser General Public License for more details.
      13             : 
      14             : // You should have received a copy of the GNU Lesser General Public
      15             : // License along with this library; if not, write to the Free Software
      16             : // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
      17             : 
      18             : 
      19             : 
      20             : #ifndef LIBMESH_LINEAR_IMPLICIT_SYSTEM_H
      21             : #define LIBMESH_LINEAR_IMPLICIT_SYSTEM_H
      22             : 
      23             : // Local Includes
      24             : #include "libmesh/implicit_system.h"
      25             : 
      26             : // C++ includes
      27             : #include <cstddef>
      28             : 
      29             : namespace libMesh
      30             : {
      31             : 
      32             : 
      33             : // Forward Declarations
      34             : template <typename T> class LinearSolver;
      35             : template <typename T> class ShellMatrix;
      36             : 
      37             : 
      38             : /**
      39             :  * \brief Manages consistently variables, degrees of freedom, coefficient
      40             :  * vectors, matrices and linear solvers for implicit systems.
      41             :  *
      42             :  * An implicit system is a system that requires the solution of a
      43             :  * system of equations. This class has the ability to create and use a
      44             :  * linear solver to solve the system.
      45             :  *
      46             :  * The matrix LinearImplicitSystem::matrix and the vector
      47             :  * LinearImplicitSystem::rhs should be filled during assembly.
      48             :  *
      49             :  * \note Additional vectors/matrices can be added via parent class
      50             :  * interfaces.
      51             :  *
      52             :  * \author Benjamin Kirk
      53             :  * \date 2005
      54             :  */
      55        1240 : class LinearImplicitSystem : public ImplicitSystem
      56             : {
      57             : public:
      58             : 
      59             :   /**
      60             :    * Constructor.
      61             :    */
      62             :   LinearImplicitSystem (EquationSystems & es,
      63             :                         const std::string & name,
      64             :                         const unsigned int number);
      65             : 
      66             :   /**
      67             :    * Special functions.
      68             :    * - This class has the same restrictions/defaults as its base class.
      69             :    * - The destructor is defaulted out-of-line.
      70             :    */
      71             :   LinearImplicitSystem (const LinearImplicitSystem &) = delete;
      72             :   LinearImplicitSystem & operator= (const LinearImplicitSystem &) = delete;
      73             :   LinearImplicitSystem (LinearImplicitSystem &&) = default;
      74             :   LinearImplicitSystem & operator= (LinearImplicitSystem &&) = delete;
      75             :   virtual ~LinearImplicitSystem ();
      76             : 
      77             :   /**
      78             :    * The type of system.
      79             :    */
      80             :   typedef LinearImplicitSystem sys_type;
      81             : 
      82             :   /**
      83             :    * The type of the parent.
      84             :    */
      85             :   typedef ImplicitSystem Parent;
      86             : 
      87             :   /**
      88             :    * \returns A reference to *this.
      89             :    */
      90             :   sys_type & system () { return *this; }
      91             : 
      92             :   /**
      93             :    * Clear all the data structures associated with
      94             :    * the system.
      95             :    */
      96             :   virtual void clear () override;
      97             : 
      98             :   /**
      99             :    * Initializes new data members of the system
     100             :    */
     101             :   virtual void init_data () override;
     102             : 
     103             :   /**
     104             :    * Reinitializes the member data fields associated with
     105             :    * the system, so that, e.g., \p assemble() may be used.
     106             :    */
     107             :   virtual void reinit () override;
     108             : 
     109             :   /**
     110             :    * Prepares \p matrix and \p _dof_map for matrix assembly.
     111             :    * Does not actually assemble anything.  For matrix assembly,
     112             :    * use the \p assemble() in derived classes.
     113             :    * Should be overridden in derived classes.
     114             :    */
     115       38939 :   virtual void assemble () override { ImplicitSystem::assemble(); }
     116             : 
     117             :   /**
     118             :    * After calling this method, any solve will be limited to the given
     119             :    * subset.  To disable this mode, call this method with \p subset
     120             :    * being a \p nullptr.
     121             :    */
     122             :   virtual void restrict_solve_to (const SystemSubset * subset,
     123             :                                   const SubsetSolveMode subset_solve_mode=SUBSET_ZERO) override;
     124             : 
     125             :   /**
     126             :    * Assembles & solves the linear system A*x=b.
     127             :    */
     128             :   virtual void solve () override;
     129             : 
     130             :   /**
     131             :    * \returns A pointer to a linear solver appropriate for use in
     132             :    * adjoint and/or sensitivity solves
     133             :    */
     134             :   virtual LinearSolver<Number> * get_linear_solver() const override;
     135             : 
     136             :   /**
     137             :    * Assembles a residual in \p rhs and/or a jacobian in \p matrix,
     138             :    * as requested.
     139             :    */
     140             :   virtual void assembly(bool get_residual,
     141             :                         bool get_jacobian,
     142             :                         bool apply_heterogeneous_constraints = false,
     143             :                         bool apply_no_constraints = false) override;
     144             : 
     145             :   /**
     146             :    * \returns \p "LinearImplicit".  Helps in identifying
     147             :    * the system type in an equation system file.
     148             :    */
     149       10754 :   virtual std::string system_type () const override { return "LinearImplicit"; }
     150             : 
     151             :   /**
     152             :    * \returns The number of iterations
     153             :    * taken for the most recent linear solve.
     154             :    */
     155           0 :   unsigned int n_linear_iterations() const { return _n_linear_iterations; }
     156             : 
     157             :   /**
     158             :    * \returns The final residual for the linear system solve.
     159             :    */
     160           0 :   Real final_linear_residual() const { return _final_linear_residual; }
     161             : 
     162             :   /**
     163             :    * This function enables the user to provide a shell matrix, i.e. a
     164             :    * matrix that is not stored element-wise, but as a function.  When
     165             :    * you register your shell matrix using this function, calling \p
     166             :    * solve() will no longer use the \p matrix member but the
     167             :    * registered shell matrix instead.  You can reset this behaviour to
     168             :    * its original state by supplying a \p nullptr to this
     169             :    * function.
     170             :    */
     171             :   void attach_shell_matrix (ShellMatrix<Number> * shell_matrix);
     172             : 
     173             :   /**
     174             :    * Detaches a shell matrix.  Same as \p attach_shell_matrix(nullptr).
     175             :    */
     176             :   void detach_shell_matrix () { attach_shell_matrix(nullptr); }
     177             : 
     178             :   /**
     179             :    * \returns A pointer to the currently attached shell matrix, if any,
     180             :    * otherwise \p nullptr.
     181             :    */
     182             :   ShellMatrix<Number> * get_shell_matrix() { return _shell_matrix; }
     183             : 
     184             :   virtual void create_static_condensation() override;
     185             : 
     186             : protected:
     187             : 
     188             :   /**
     189             :    * The number of linear iterations required to solve the linear
     190             :    * system Ax=b.
     191             :    */
     192             :   unsigned int _n_linear_iterations;
     193             : 
     194             :   /**
     195             :    * The final residual for the linear system Ax=b.
     196             :    */
     197             :   Real _final_linear_residual;
     198             : 
     199             :   /**
     200             :    * User supplies shell matrix or \p nullptr if no shell matrix is used.
     201             :    */
     202             :   ShellMatrix<Number> * _shell_matrix;
     203             : 
     204             :   /**
     205             :    * The current subset on which to solve (or \p nullptr if none).
     206             :    */
     207             :   const SystemSubset * _subset;
     208             : 
     209             :   /**
     210             :    * If restrict-solve-to-subset mode is active, this member decides
     211             :    * what happens with the dofs outside the subset.
     212             :    */
     213             :   SubsetSolveMode _subset_solve_mode;
     214             : };
     215             : 
     216             : } // namespace libMesh
     217             : 
     218             : #endif // LIBMESH_LINEAR_IMPLICIT_SYSTEM_H