Line data    Source code

       1             : //* This file is part of the MOOSE framework
       2             : //* https://mooseframework.inl.gov
       3             : //*
       4             : //* All rights reserved, see COPYRIGHT for full restrictions
       5             : //* https://github.com/idaholab/moose/blob/master/COPYRIGHT
       6             : //*
       7             : //* Licensed under LGPL 2.1, please see LICENSE for details
       8             : //* https://www.gnu.org/licenses/lgpl-2.1.html
       9             : 
      10             : #pragma once
      11             : 
      12             : #include "ExplicitTimeIntegrator.h"
      13             : 
      14             : // Forward declarations
      15             : namespace libMesh
      16             : {
      17             : template <typename T>
      18             : class SparseMatrix;
      19             : }
      20             : 
      21             : /**
      22             :  * Implements a form of the central difference time integrator that calculates acceleration directly
      23             :  * from the residual forces.
      24             :  */
      25             : class ExplicitMixedOrder : public ExplicitTimeIntegrator
      26             : {
      27             : public:
      28             :   static InputParameters validParams();
      29             : 
      30             :   ExplicitMixedOrder(const InputParameters & parameters);
      31             : 
      32           0 :   virtual int order() override { return 1; }
      33             :   virtual void computeTimeDerivatives() override;
      34             : 
      35             :   virtual void solve() override;
      36             :   virtual void postResidual(NumericVector<Number> & residual) override;
      37         696 :   virtual bool overridesSolve() const override { return true; }
      38             : 
      39         348 :   virtual void postSolve() override
      40             :   { // Once we have the new solution, we want to adanceState to make sure the
      41             :     // coupling between the solution and the computed material properties is kept correctly.
      42         348 :     _fe_problem.advanceState();
      43         348 :   }
      44         348 :   virtual bool advancesProblemState() const override { return true; }
      45             : 
      46             :   virtual bool performExplicitSolve(SparseMatrix<Number> & mass_matrix) override;
      47             : 
      48           0 :   void computeADTimeDerivatives(ADReal &, const dof_id_type &, ADReal &) const override
      49             :   {
      50           0 :     mooseError("NOT SUPPORTED");
      51             :   }
      52             :   virtual void init() override;
      53             : 
      54             :   enum TimeOrder
      55             :   {
      56             :     FIRST,
      57             :     SECOND
      58             :   };
      59             : 
      60             :   /**
      61             :    * Retrieve the order of the highest time derivative of a variable.
      62             :    * @return Returns the time order enum of this variable.
      63             :    */
      64             :   TimeOrder findVariableTimeOrder(unsigned int var_num) const;
      65             : 
      66             : protected:
      67             :   virtual TagID massMatrixTagID() const override;
      68             : 
      69             :   /// Whether we are reusing the mass matrix
      70             :   const bool & _constant_mass;
      71             : 
      72             :   /// Mass matrix name
      73             :   const TagName & _mass_matrix;
      74             : 
      75             :   /// The older solution
      76             :   const NumericVector<Number> & _solution_older;
      77             : 
      78             :   // Variables that forward Euler time integration will be used for
      79             :   std::unordered_set<unsigned int> & _vars_first;
      80             : 
      81             :   // local dofs that will have forward euler time integration
      82             :   std::vector<dof_id_type> & _local_first_order_indices;
      83             : 
      84             :   // Variables that central difference time integration will be used for
      85             :   std::unordered_set<unsigned int> & _vars_second;
      86             : 
      87             :   // local dofs that will have central difference time integration
      88             :   std::vector<dof_id_type> & _local_second_order_indices;
      89             : 
      90             :   /**
      91             :    * Helper function that actually does the math for computing the time derivative
      92             :    */
      93             :   template <typename T, typename T2, typename T3, typename T4>
      94             :   void
      95             :   computeTimeDerivativeHelper(T & u_dot, T2 & u_dotdot, const T3 & u_old, const T4 & u_older) const;
      96             : 
      97             :   void computeICs();
      98             : };
      99             : 
     100             : template <typename T, typename T2, typename T3, typename T4>
     101             : void
     102             : ExplicitMixedOrder::computeTimeDerivativeHelper(T & u_dot,
     103             :                                                 T2 & u_dotdot,
     104             :                                                 const T3 & u_old,
     105             :                                                 const T4 & u_older) const
     106             : {
     107             :   // computing first derivative
     108             :   // using the Central Difference method
     109             :   // u_dot_old = (first_term - second_term) / 2 / dt
     110             :   //       first_term = u
     111             :   //      second_term = u_older
     112             :   u_dot -= u_older; // 'older than older' solution
     113             :   u_dot *= 1.0 / (2.0 * _dt);
     114             : 
     115             :   // computing second derivative
     116             :   // using the Central Difference method
     117             :   // u_dotdot_old = (first_term - second_term + third_term) / dt / dt
     118             :   //       first_term = u
     119             :   //      second_term = 2 * u_old
     120             :   //       third_term = u_older
     121             :   u_dotdot -= u_old;
     122             :   u_dotdot -= u_old;
     123             :   u_dotdot += u_older;
     124             :   u_dotdot *= 1.0 / (_dt * _dt);
     125             : }