Line data    Source code

       1             : // The libMesh Finite Element Library.
       2             : // Copyright (C) 2002-2026 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             : #ifndef LIBMESH_CONSTRAINT_ELIMINATION_DOF_MAP_H
      19             : #define LIBMESH_CONSTRAINT_ELIMINATION_DOF_MAP_H
      20             : 
      21             : #include "libmesh/reduced_dof_map.h"
      22             : 
      23             : namespace libMesh
      24             : {
      25             : 
      26             : /**
      27             :  * The reduced space of the unconstrained degrees of freedom of a \p DofMap.
      28             :  *
      29             :  * Every \p DofMap constraint is affine: the full solution is \f$ x = C y + h \f$, where \f$ y \f$
      30             :  * holds the unconstrained degrees of freedom, \f$ C \f$ is the identity on them and holds the
      31             :  * constraint coefficients on constrained rows, and \f$ h \f$ holds the constraint values. The
      32             :  * reduced residual and Jacobian are \f$ C^T F(C y + h) \f$ and \f$ C^T J C \f$. Element matrices
      33             :  * and vectors constrained with \p DofMap::constrain_element_matrix() and its relatives are \f$ C^T
      34             :  * K C \f$ and \f$ C^T F \f$ on their unconstrained rows and columns, so dropping their constrained
      35             :  * rows and columns at insertion assembles the reduced system exactly.
      36             :  */
      37          56 : class ConstraintEliminationDofMap : public ReducedDofMap
      38             : {
      39             : public:
      40             :   ConstraintEliminationDofMap(MeshBase & mesh, System & system, const DofMap & dof_map);
      41             :   virtual ~ConstraintEliminationDofMap();
      42             : 
      43             :   /**
      44             :    * Unconstrained degrees of freedom are retained
      45             :    */
      46             :   virtual bool retain_field_dof(const Elem & elem,
      47             :                                 unsigned int node_num,
      48             :                                 unsigned int var_num,
      49             :                                 dof_id_type field_dof) const override;
      50             : 
      51             :   /**
      52             :    * Unconstrained degrees of freedom are retained
      53             :    */
      54             :   virtual bool retain_scalar_dof(dof_id_type scalar_dof) const override;
      55             : 
      56             : private:
      57             :   bool is_unconstrained(dof_id_type dof) const;
      58             : };
      59             : 
      60             : }
      61             : 
      62             : #endif // LIBMESH_CONSTRAINT_ELIMINATION_DOF_MAP_H