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             : #include "PorousFlowLumpedKernelBase.h"
      11             : 
      12             : template <bool is_ad>
      13        4622 : PorousFlowLumpedKernelBaseTempl<is_ad>::PorousFlowLumpedKernelBaseTempl(
      14             :     const InputParameters & parameters)
      15        4622 :   : GenericKernel<is_ad>(parameters)
      16             : {
      17             :   // Mass lumping evaluates each residual row using the nodal material property at that node, which
      18             :   // identifies each element test function with a mesh node.  This is only valid for nodal
      19             :   // (Lagrange) variables.
      20        4622 :   if (!_var.isNodal())
      21           2 :     mooseError("The variable '",
      22           2 :                _var.name(),
      23             :                "' is not a nodal (Lagrange) variable.  This kernel uses mass lumping, which "
      24             :                "requires a nodal variable.  For non-nodal variables use the non-lumped "
      25             :                "PorousFlowFullySaturated* kernels instead.");
      26        4620 : }
      27             : 
      28             : template <bool is_ad>
      29             : void
      30      151065 : PorousFlowLumpedKernelBaseTempl<is_ad>::jacobianSetup()
      31             : {
      32      151065 :   GenericKernel<is_ad>::jacobianSetup();
      33      151065 :   _my_elem_lma = nullptr;
      34      151065 : }
      35             : 
      36             : // AD-path Jacobian assembly for kernels that use mass-lumped (nodal) material properties.
      37             : //
      38             : // The default ADKernel path (ADKernel::computeADJacobian -> addJacobian) routes through
      39             : // Assembly::cacheJacobian, which takes the sparse column set from residuals[0] and reuses it for
      40             : // every row.  That assumes every test function's residual depends on the same set of DOFs, which
      41             : // holds for ordinary qp-based weak forms because the solution at any QP is sum_j u_j*phi_j(qp)
      42             : // and therefore involves every element DOF.
      43             : //
      44             : // With mass lumping each residual row _i depends only on the nodal material properties at node _i
      45             : // (i.e. on the DOFs at node _i alone), so the column set from residuals[0] is only valid for row 0;
      46             : // the off-node rows are assembled against the wrong columns and come out zero.
      47             : //
      48             : // addJacobianWithoutConstraints reads each row's own column indices from
      49             : // residuals[_i].derivatives().nude_indices(), giving the correct per-node block structure.
      50             : //
      51             : // This is consistent with how the framework handles analogous cases:
      52             : //   - ADNodalKernel::computeJacobian passes a size-1 residual array; Assembly::cacheJacobian's
      53             : //     residuals.size()==1 branch falls straight through to cacheJacobianWithoutConstraints.
      54             : //   - MassLumpedTimeDerivative::computeJacobian (non-AD) overrides assembly to fill only the
      55             : //     node-diagonal entries, for the same structural reason.
      56             : //
      57             : // constrain_element_matrix is therefore skipped.  It cannot be applied to a node-diagonal block
      58             : // structure: the constraint machinery assumes a fully-coupled local matrix where all rows share a
      59             : // column space.  Neither the non-AD lumped path nor the framework AD nodal path applies it either.
      60             : template <bool is_ad>
      61             : void
      62     3062116 : PorousFlowLumpedKernelBaseTempl<is_ad>::computeJacobian()
      63             : {
      64             :   if constexpr (!is_ad)
      65     3062116 :     GenericKernel<is_ad>::computeJacobian();
      66             :   else
      67             :   {
      68           0 :     if (_my_elem_lma != this->_current_elem)
      69             :     {
      70           0 :       this->computeResidualsForJacobian();
      71           0 :       this->addJacobianWithoutConstraints(
      72           0 :           this->_assembly, this->_residuals, this->dofIndices(), this->_var.scalingFactor());
      73           0 :       _my_elem_lma = this->_current_elem;
      74             :     }
      75             :   }
      76     3062116 : }
      77             : 
      78             : // A single AD residual evaluation carries derivatives wrt every coupled variable, so the
      79             : // off-diagonal blocks are assembled by the same addJacobianWithoutConstraints call as the diagonal.
      80             : // _my_elem_lma caches the element so computation happens once per element rather than once per
      81             : // coupled jvar, mirroring ADKernel's own _my_elem guard in ADKernel::computeOffDiagJacobian.
      82             : template <bool is_ad>
      83             : void
      84     6423397 : PorousFlowLumpedKernelBaseTempl<is_ad>::computeOffDiagJacobian(unsigned int jvar)
      85             : {
      86             :   if constexpr (!is_ad)
      87     6423329 :     GenericKernel<is_ad>::computeOffDiagJacobian(jvar);
      88             :   else
      89             :   {
      90             :     libmesh_ignore(jvar);
      91          68 :     if (_my_elem_lma != this->_current_elem)
      92             :     {
      93          36 :       this->computeResidualsForJacobian();
      94          36 :       this->addJacobianWithoutConstraints(
      95          36 :           this->_assembly, this->_residuals, this->dofIndices(), this->_var.scalingFactor());
      96          36 :       _my_elem_lma = this->_current_elem;
      97             :     }
      98             :   }
      99     6423397 : }
     100             : 
     101             : template class PorousFlowLumpedKernelBaseTempl<false>;
     102             : template class PorousFlowLumpedKernelBaseTempl<true>;