OGS
ProcessLib::CentralDifferencesJacobianAssembler Class Referencefinal

Detailed Description

Assembles the Jacobian matrix using central differences.

Definition at line 18 of file CentralDifferencesJacobianAssembler.h.

#include <CentralDifferencesJacobianAssembler.h>

Inheritance diagram for ProcessLib::CentralDifferencesJacobianAssembler:
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Collaboration diagram for ProcessLib::CentralDifferencesJacobianAssembler:
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Public Member Functions

 CentralDifferencesJacobianAssembler (std::vector< double > &&absolute_epsilons)
void assembleWithJacobian (LocalAssemblerInterface &local_assembler, double const t, double const dt, std::vector< double > const &local_x_data, std::vector< double > const &local_x_prev_data, std::vector< double > &local_b_data, std::vector< double > &local_Jac_data) override
std::unique_ptr< AbstractJacobianAssembler > copy () const override
Public Member Functions inherited from ProcessLib::AbstractJacobianAssembler
 AbstractJacobianAssembler (std::vector< double > const &&absolute_epsilons)
 AbstractJacobianAssembler ()
virtual void assembleWithJacobianForStaggeredScheme (LocalAssemblerInterface &, double const, double const, Eigen::VectorXd const &, Eigen::VectorXd const &, int const, std::vector< double > &, std::vector< double > &)
virtual ~AbstractJacobianAssembler ()=default
void checkPerturbationSize (int const max_non_deformation_dofs_per_node) const
void setNonDeformationComponentIDs (std::vector< int > const &non_deformation_component_ids)
void setNonDeformationComponentIDsNoSizeCheck (std::vector< int > const &non_deformation_component_ids)
auto getVariableComponentEpsilonsView () const
auto isPerturbationEnabled () const

Private Attributes

std::vector< double > _local_M_data
std::vector< double > _local_K_data
std::vector< double > _local_b_data
std::vector< double > _local_x_perturbed_data

Additional Inherited Members

Protected Attributes inherited from ProcessLib::AbstractJacobianAssembler
std::vector< int > non_deformation_component_ids_
std::vector< double > const absolute_epsilons_

Constructor & Destructor Documentation

◆ CentralDifferencesJacobianAssembler()

ProcessLib::CentralDifferencesJacobianAssembler::CentralDifferencesJacobianAssembler ( std::vector< double > && absolute_epsilons)
explicit

Constructs a new instance.

Parameters
absolute_epsilonsperturbations of the variable components used for evaluating the finite differences.
Note
The size of absolute_epsilons defines the "number of components" of the local solution vector (This is not the number of elements of the vector!). Therefore the size of the local solution vector must be divisible by the size of absolute_epsilons. This is the only consistency check performed. It is not checked whether said "number of components" is sensible. E.g., one could pass one epsilon per node, which would be valid but would not make sense at all.

Definition at line 13 of file CentralDifferencesJacobianAssembler.cpp.

15 : AbstractJacobianAssembler(std::move(absolute_epsilons))
16{
17}

References ProcessLib::AbstractJacobianAssembler::AbstractJacobianAssembler().

Member Function Documentation

◆ assembleWithJacobian()

void ProcessLib::CentralDifferencesJacobianAssembler::assembleWithJacobian ( LocalAssemblerInterface & local_assembler,
double const t,
double const dt,
std::vector< double > const & local_x_data,
std::vector< double > const & local_x_prev_data,
std::vector< double > & local_b_data,
std::vector< double > & local_Jac_data )
overridevirtual

Assembles the Jacobian, the matrices \(M\) and \(K\), and the vector \(b\). For the assembly the assemble() method of the given local_assembler is called several times and the Jacobian is built from finite differences. The number of calls of the assemble() method is \(2N+1\) if \(N\) is the size of local_x_data.

Attention
It is assumed that the local vectors and matrices are ordered by component.

Implements ProcessLib::AbstractJacobianAssembler.

Definition at line 19 of file CentralDifferencesJacobianAssembler.cpp.

24{
25 std::vector<double> local_M_data(local_Jac_data.size());
26 std::vector<double> local_K_data(local_Jac_data.size());
27
28 auto const num_r_c =
29 static_cast<Eigen::MatrixXd::Index>(local_x_data.size());
30
31 auto const local_x =
32 MathLib::toVector<Eigen::VectorXd>(local_x_data, num_r_c);
33 auto const local_x_prev =
34 MathLib::toVector<Eigen::VectorXd>(local_x_prev_data, num_r_c);
35 Eigen::VectorXd const local_xdot = (local_x - local_x_prev) / dt;
36
37 auto local_Jac =
38 MathLib::createZeroedMatrix(local_Jac_data, num_r_c, num_r_c);
39 _local_x_perturbed_data = local_x_data;
40
41 assert(this->non_deformation_component_ids_.size() > 0);
42 auto const num_dofs_per_component =
43 local_x_data.size() / this->non_deformation_component_ids_.size();
44
45 auto const nved = local_assembler.getNumberOfVectorElementsForDeformation();
46
47 // Residual res := M xdot + K x - b
48 // Computing Jac := dres/dx
49 // = M dxdot/dx + dM/dx xdot + K dx/dx + dK/dx x - db/dx
50 // with dxdot/dx = 1/dt and dx/dx = 1
51 // (Note: dM/dx and dK/dx actually have the second and
52 // third index transposed.)
53 // The loop computes the dM/dx, dK/dx and db/dx terms, the rest is computed
54 // afterwards. The loop skips the entries corresponding to the deformation
55 // part of the solution vector if a vector segment size is given by nved.
56 // This is to avoid recomputing the analytic block of the deformation
57 // process.
58 auto const num_purterbated_colums = num_r_c - nved;
59 auto const perturbations = this->getVariableComponentEpsilonsView();
60 for (Eigen::MatrixXd::Index i = 0; i < num_purterbated_colums; ++i)
61 {
62 // assume that local_x_data is ordered by component.
63 auto const component = i / num_dofs_per_component;
64 auto const eps = perturbations[component];
65
66 _local_x_perturbed_data[i] += eps;
67 local_assembler.assemble(t, dt, _local_x_perturbed_data,
68 local_x_prev_data, local_M_data, local_K_data,
69 local_b_data);
70
71 _local_x_perturbed_data[i] = local_x_data[i] - eps;
72 local_assembler.assemble(t, dt, _local_x_perturbed_data,
73 local_x_prev_data, _local_M_data,
74 _local_K_data, _local_b_data);
75
76 _local_x_perturbed_data[i] = local_x_data[i];
77
78 if (!local_M_data.empty())
79 {
80 auto const local_M_p =
81 MathLib::toMatrix(local_M_data, num_r_c, num_r_c);
82 auto const local_M_m =
83 MathLib::toMatrix(_local_M_data, num_r_c, num_r_c);
84 local_Jac.col(i).noalias() +=
85 // dM/dxi * x_dot
86 (local_M_p - local_M_m) * local_xdot / (2.0 * eps);
87 local_M_data.clear();
88 _local_M_data.clear();
89 }
90 if (!local_K_data.empty())
91 {
92 auto const local_K_p =
93 MathLib::toMatrix(local_K_data, num_r_c, num_r_c);
94 auto const local_K_m =
95 MathLib::toMatrix(_local_K_data, num_r_c, num_r_c);
96 local_Jac.col(i).noalias() +=
97 // dK/dxi * x
98 (local_K_p - local_K_m) * local_x / (2.0 * eps);
99 local_K_data.clear();
100 _local_K_data.clear();
101 }
102 if (!local_b_data.empty())
103 {
104 auto const local_b_p =
105 MathLib::toVector<Eigen::VectorXd>(local_b_data, num_r_c);
106 auto const local_b_m =
107 MathLib::toVector<Eigen::VectorXd>(_local_b_data, num_r_c);
108 local_Jac.col(i).noalias() -=
109 // db/dxi
110 (local_b_p - local_b_m) / (2.0 * eps);
111 local_b_data.clear();
112 _local_b_data.clear();
113 }
114 }
115
116 // Assemble with unperturbed local x, i.e. compute M dxdot/dx + K dx/dx =
117 // M/dt + K
118 local_assembler.assemble(t, dt, local_x_data, local_x_prev_data,
119 local_M_data, local_K_data, local_b_data);
120
121 // Compute remaining terms of the Jacobian.
122 if (!local_M_data.empty())
123 {
124 auto local_M = MathLib::toMatrix(local_M_data, num_r_c, num_r_c);
125 local_Jac.noalias() += local_M / dt;
126 }
127 if (!local_K_data.empty())
128 {
129 auto local_K = MathLib::toMatrix(local_K_data, num_r_c, num_r_c);
130 local_Jac.noalias() += local_K;
131 }
132
133 // Move the M and K contributions to the residuum for evaluation of nodal
134 // forces, flow rates, and the like. Cleaning up the M's and K's storage so
135 // it is not accounted for twice.
136 auto b = [&]()
137 {
138 if (!local_b_data.empty())
139 {
140 return MathLib::toVector<Eigen::VectorXd>(local_b_data, num_r_c);
141 }
142 return MathLib::createZeroedVector<Eigen::VectorXd>(local_b_data,
143 num_r_c);
144 }();
145
146 if (!local_M_data.empty())
147 {
148 auto M = MathLib::toMatrix(local_M_data, num_r_c, num_r_c);
149 b -= M * local_xdot;
150 local_M_data.clear();
151 }
152 if (!local_K_data.empty())
153 {
154 auto K = MathLib::toMatrix(local_K_data, num_r_c, num_r_c);
155
156 // Note: The deformation segment of \c b is already computed as
157 // int{B^T sigma}dA, which is identical to K_uu * u. Therefore the
158 // corresponding K block is set to zero.
159 if (nved != 0)
160 {
161 auto const dm_start_index = num_purterbated_colums;
162 auto const dm_size = nved;
163 K.block(dm_start_index, dm_start_index, dm_size, dm_size).setZero();
164 }
165
166 b -= K * local_x;
167 local_K_data.clear();
168 }
169}
MathLib::createZeroedVector
Eigen::Map< Vector > createZeroedVector(std::vector< double > &data, Eigen::VectorXd::Index size)
Definition EigenMapTools.h:146
MathLib::toVector
Eigen::Map< const Vector > toVector(std::vector< double > const &data, Eigen::VectorXd::Index size)
Creates an Eigen mapped vector from the given data vector.
Definition EigenMapTools.h:160
MathLib::createZeroedMatrix
Eigen::Map< Matrix > createZeroedMatrix(std::vector< double > &data, Eigen::MatrixXd::Index rows, Eigen::MatrixXd::Index cols)
Definition EigenMapTools.h:25
MathLib::toMatrix
Eigen::Map< const Matrix > toMatrix(std::vector< double > const &data, Eigen::MatrixXd::Index rows, Eigen::MatrixXd::Index cols)
Definition EigenMapTools.h:65

References _local_b_data, _local_K_data, _local_M_data, _local_x_perturbed_data, ProcessLib::LocalAssemblerInterface::assemble(), MathLib::createZeroedMatrix(), MathLib::createZeroedVector(), ProcessLib::LocalAssemblerInterface::getNumberOfVectorElementsForDeformation(), ProcessLib::AbstractJacobianAssembler::getVariableComponentEpsilonsView(), ProcessLib::AbstractJacobianAssembler::non_deformation_component_ids_, MathLib::toMatrix(), and MathLib::toVector().

◆ copy()

std::unique_ptr< AbstractJacobianAssembler > ProcessLib::CentralDifferencesJacobianAssembler::copy ( ) const
overridevirtual

Implements ProcessLib::AbstractJacobianAssembler.

Definition at line 172 of file CentralDifferencesJacobianAssembler.cpp.

173{
174 return std::make_unique<CentralDifferencesJacobianAssembler>(*this);
175}

Member Data Documentation

◆ _local_b_data

std::vector<double> ProcessLib::CentralDifferencesJacobianAssembler::_local_b_data
private

Definition at line 61 of file CentralDifferencesJacobianAssembler.h.

Referenced by assembleWithJacobian().

◆ _local_K_data

std::vector<double> ProcessLib::CentralDifferencesJacobianAssembler::_local_K_data
private

Definition at line 60 of file CentralDifferencesJacobianAssembler.h.

Referenced by assembleWithJacobian().

◆ _local_M_data

std::vector<double> ProcessLib::CentralDifferencesJacobianAssembler::_local_M_data
private

Definition at line 59 of file CentralDifferencesJacobianAssembler.h.

Referenced by assembleWithJacobian().

◆ _local_x_perturbed_data

std::vector<double> ProcessLib::CentralDifferencesJacobianAssembler::_local_x_perturbed_data
private

Definition at line 62 of file CentralDifferencesJacobianAssembler.h.

Referenced by assembleWithJacobian().

The documentation for this class was generated from the following files: