Line data    Source code

       1             : //* This file is part of the MOOSE framework
       2             : //* https://www.mooseframework.org
       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 "KokkosKernelBase.h"
      13             : 
      14             : namespace Moose::Kokkos
      15             : {
      16             : 
      17             : /**
      18             :  * The base class for a user to derive their own Kokkos kernels using automatic differentiation
      19             :  * (AD).
      20             :  *
      21             :  * The user should define computeQpResidual() as inlined public method in their derived class (not
      22             :  * virtual override). The signature of computeQpResidual() expected to be defined in the derived
      23             :  * class is as follows:
      24             :  *
      25             :  * @tparam Derived The object type
      26             :  * @param i The element-local DOF index
      27             :  * @param qp The local quadrature point index
      28             :  * @param datum The AssemblyDatum object of the current thread
      29             :  * @returns The residual contribution
      30             :  *
      31             :  * template <typename Derived>
      32             :  * KOKKOS_FUNCTION Moose::Kokkos::ADReal computeQpResidual(const unsigned int i,
      33             :  *                                                         const unsigned int qp,
      34             :  *                                                         AssemblyDatum & datum) const;
      35             :  *
      36             :  * Note that computeQpJacobian() and computeQpOffDiagJacobian() are unused for AD kernels.
      37             :  */
      38             : class ADKernel : public KernelBase
      39             : {
      40             : public:
      41             :   static InputParameters validParams();
      42             : 
      43             :   /**
      44             :    * Constructor
      45             :    */
      46             :   ADKernel(const InputParameters & parameters);
      47             : 
      48             :   virtual void computeResidual() override;
      49             :   virtual void computeJacobian() override;
      50             :   virtual void computeResidualAndJacobian() override;
      51             : 
      52             :   /**
      53             :    * The parallel computation entry function called by Kokkos
      54             :    */
      55             :   template <typename Derived>
      56             :   KOKKOS_FUNCTION void operator()(ResidualLoop, const ThreadID tid, const Derived & kernel) const;
      57             : 
      58             :   /**
      59             :    * Compute residual
      60             :    * @param kernel The kernel object of the final derived type
      61             :    * @param datum The AssemblyDatum object of the current thread
      62             :    */
      63             :   template <typename Derived>
      64             :   KOKKOS_FUNCTION void computeResidualInternal(const Derived & kernel, AssemblyDatum & datum) const;
      65             : 
      66             : protected:
      67             :   /**
      68             :    * Dispatch parallel calculation
      69             :    */
      70             :   virtual void dispatch();
      71             : 
      72             :   /**
      73             :    * Current test function
      74             :    */
      75             :   const ADVariableTestValue _test;
      76             :   /**
      77             :    * Gradient of the current test function
      78             :    */
      79             :   const ADVariableTestGradient _grad_test;
      80             :   /**
      81             :    * Current shape function
      82             :    */
      83             :   const ADVariablePhiValue _phi;
      84             :   /**
      85             :    * Gradient of the current shape function
      86             :    */
      87             :   const ADVariablePhiGradient _grad_phi;
      88             :   /**
      89             :    * Current solution at quadrature points
      90             :    */
      91             :   const ADVariableValue _u;
      92             :   /**
      93             :    * Gradient of the current solution at quadrature points
      94             :    */
      95             :   const ADVariableGradient _grad_u;
      96             :   /**
      97             :    * Whether computing residual
      98             :    */
      99             :   bool _computing_residual = false;
     100             :   /**
     101             :    * Whether computing Jacobian
     102             :    */
     103             :   bool _computing_jacobian = false;
     104             : };
     105             : 
     106             : template <typename Derived>
     107             : KOKKOS_FUNCTION void
     108     1214896 : ADKernel::operator()(ResidualLoop, const ThreadID tid, const Derived & kernel) const
     109             : {
     110     1214896 :   auto elem = kokkosBlockElementID(_thread(tid, 1));
     111             : 
     112     2429792 :   AssemblyDatum datum(elem,
     113             :                       libMesh::invalid_uint,
     114             :                       kokkosAssembly(),
     115             :                       kokkosSystems(),
     116     1214896 :                       _kokkos_var,
     117             :                       _kokkos_var.var());
     118             : 
     119     1214896 :   datum.set_local_parallel(_thread(tid, 0), _thread.size(0));
     120             : 
     121     1214896 :   datum.do_derivatives(_computing_jacobian);
     122             : 
     123     1214896 :   kernel.computeResidualInternal(kernel, datum);
     124     1214896 : }
     125             : 
     126             : template <typename Derived>
     127             : KOKKOS_FUNCTION void
     128     1214896 : ADKernel::computeResidualInternal(const Derived & kernel, AssemblyDatum & datum) const
     129             : {
     130     2393152 :   for (unsigned int i = datum.local_thread_id(); i < datum.n_dofs(); i += datum.num_local_threads())
     131             :   {
     132     1178256 :     ADReal local_re = 0;
     133             : 
     134     5818000 :     for (unsigned int qp = 0; qp < datum.n_qps(); ++qp)
     135     4639744 :       local_re += datum.JxW(qp) * kernel.template computeQpResidual<Derived>(i, qp, datum);
     136             : 
     137     1178256 :     if (_computing_residual)
     138     1174056 :       accumulateTaggedElementalResidual(local_re.value(), datum.elem().id, i);
     139     1178256 :     if (_computing_jacobian)
     140     1101876 :       accumulateTaggedElementalMatrix(local_re.derivatives(), datum, i);
     141             :   }
     142     1214896 : }
     143             : 
     144             : } // namespace Moose::Kokkos