MFEMWeakForm

Overview

The MFEMWeakForm is a MOOSE object responsible for the construction of an initialised MFEM EquationSystem, based on the set of kernels and boundary conditions provided by the user. If no MFEMWeakFormBase object is specified by the user in a real problem using an MFEMSteady executioner, a default MFEMWeakForm object will be created to set up an EquationSystem using all kernels and boundary conditions added in the input file.

Example Input File Syntax

[WeakForms<<<{"href": "../../../syntax/WeakForms/index.html"}>>>]
  [Darcy]
    type = MFEMWeakForm<<<{"description": "Builds a real-valued MFEM EquationSystem from the kernels and boundary conditions named by this weak form.", "href": "MFEMWeakForm.html"}>>>
    kernels<<<{"description": "List of kernels to add to the weak form"}>>> = 'VelocityMass PressureGrad VelocityDiv'
    bcs<<<{"description": "List of boundary conditions to add to the weak form"}>>> = 'flux_boundaries'
  []
[]

Input Parameters

bcsList of boundary conditions to add to the weak form
C++ Type:std::vector<MFEMBoundaryConditionName>
Controllable:No
Description:List of boundary conditions to add to the weak form
kernelsList of kernels to add to the weak form
C++ Type:std::vector<MFEMKernelName>
Controllable:No
Description:List of kernels to add to the weak form

Optional Parameters

control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Controllable:No
Description:Adds user-defined labels for accessing object parameters via control logic.
enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Controllable:No
Description:Set the enabled status of the MooseObject.

Advanced Parameters

Input Files

(test/tests/mfem/weakforms/real_weakform_complex_problem.i)
(test/tests/mfem/weakforms/unknown_kernel.i)
(test/tests/mfem/weakforms/named_weakform.i)
(test/tests/mfem/weakforms/ambiguous_weakform.i)
(test/tests/mfem/weakforms/unknown_bc.i)
(test/tests/mfem/problemcomposers/two_problem_composers.i)
(test/tests/mfem/weakforms/unknown_weakform.i)
(test/tests/mfem/weakforms/steady_weakform.i)

Child Objects

(framework/include/mfem/weakforms/MFEMEigenproblemWeakForm.h)
(framework/include/mfem/weakforms/MFEMTimeDependentWeakForm.h)

(test/tests/mfem/weakforms/steady_weakform.i)

!include ../kernels/darcy.i

[WeakForms]
  [Darcy]
    type = MFEMWeakForm
    kernels = 'VelocityMass PressureGrad VelocityDiv'
    bcs = 'flux_boundaries'
  []
[]

(test/tests/mfem/weakforms/real_weakform_complex_problem.i)

# Include mfem/complex/complex.i
!include ../complex/complex.i

# A real weak form cannot consume the complex boundary conditions of a complex problem.
[WeakForms]
  [Complex]
    type = MFEMWeakForm
    kernels = 'diffusion_complex mass_complex'
    bcs = 'dbc'
  []
[]

(test/tests/mfem/weakforms/named_weakform.i)

!include ../kernels/darcy.i

# Two weak forms are present, so the problem composer and the solver must each name the one
# whose equation system they act on.
[WeakForms]
  [Darcy]
    type = MFEMWeakForm
    kernels = 'VelocityMass PressureGrad VelocityDiv'
    bcs = 'flux_boundaries'
  []
  [VelocityOnly]
    type = MFEMWeakForm
    kernels = 'VelocityMass'
    bcs = 'flux_boundaries'
  []
[]

[ProblemComposers]
  [Darcy]
    type = MFEMWeakFormProblemComposer
    weak_form = Darcy
  []
[]

[Solvers]
  [main]
    weak_form = Darcy
  []
[]

(test/tests/mfem/weakforms/ambiguous_weakform.i)

!include ../kernels/darcy.i

# Two weak forms, but nothing names which one the default problem composer should use.
[WeakForms]
  [Darcy]
    type = MFEMWeakForm
    kernels = 'VelocityMass PressureGrad VelocityDiv'
    bcs = 'flux_boundaries'
  []
  [VelocityOnly]
    type = MFEMWeakForm
    kernels = 'VelocityMass'
    bcs = 'flux_boundaries'
  []
[]

(test/tests/mfem/weakforms/unknown_bc.i)

!include ../kernels/darcy.i

[WeakForms]
  [Darcy]
    type = MFEMWeakForm
    kernels = 'VelocityMass PressureGrad VelocityDiv'
    bcs = 'NotABC'
  []
[]

(test/tests/mfem/problemcomposers/two_problem_composers.i)

# Two decoupled Poisson problems on the same mesh, each with its own EquationSystem built by its
# own weak form and solved by its own ProblemOperator. Each problem has constant Dirichlet data on
# every boundary, so the exact solution of each is that constant: u1 == 1 and u2 == 2. The
# postprocessors therefore report zero error only if both operators solve their own system without
# disturbing the other.

[Mesh]
  type = MFEMFileMesh
  file = ../mesh/star.mesh
[]

[Problem]
  type = MFEMProblem
[]

[FESpaces]
  [H1FESpace]
    type = MFEMScalarFESpace
    fec_type = H1
    fec_order = FIRST
  []
[]

[Variables]
  [u1]
    type = MFEMVariable
    fespace = H1FESpace
  []
  [u2]
    type = MFEMVariable
    fespace = H1FESpace
  []
[]

[BCs]
  [u1_boundaries]
    type = MFEMScalarDirichletBC
    variable = u1
    boundary = '1'
    coefficient = 1.0
  []
  [u2_boundaries]
    type = MFEMScalarDirichletBC
    variable = u2
    boundary = '1'
    coefficient = 2.0
  []
[]

[Kernels]
  [diff_u1]
    type = MFEMDiffusionKernel
    variable = u1
  []
  [diff_u2]
    type = MFEMDiffusionKernel
    variable = u2
  []
[]

[WeakForms]
  [FirstSystem]
    type = MFEMWeakForm
    kernels = 'diff_u1'
    bcs = 'u1_boundaries'
  []
  [SecondSystem]
    type = MFEMWeakForm
    kernels = 'diff_u2'
    bcs = 'u2_boundaries'
  []
[]

[ProblemComposers]
  [FirstOperator]
    type = MFEMWeakFormProblemComposer
    weak_form = FirstSystem
  []
  [SecondOperator]
    type = MFEMWeakFormProblemComposer
    weak_form = SecondSystem
  []
[]

[Solvers]
  [main]
    type = MFEMMUMPS
    weak_form = FirstSystem
  []
[]

[Executioner]
  type = MFEMSteady
  device = cpu
[]

[Postprocessors]
  [u1_error]
    type = MFEML2Error
    variable = u1
    function = 1.0
  []
  [u2_error]
    type = MFEML2Error
    variable = u2
    function = 2.0
  []
[]

[Outputs]
  [TwoComposersCSV]
    type = CSV
    file_base = OutputData/TwoProblemComposers
  []
[]

(test/tests/mfem/weakforms/unknown_weakform.i)

!include ../kernels/darcy.i

[WeakForms]
  [Darcy]
    type = MFEMWeakForm
    kernels = 'VelocityMass PressureGrad VelocityDiv'
    bcs = 'flux_boundaries'
  []
[]

[Solvers]
  [main]
    weak_form = NotAWeakForm
  []
[]

(test/tests/mfem/weakforms/steady_weakform.i)

!include ../kernels/darcy.i

[WeakForms]
  [Darcy]
    type = MFEMWeakForm
    kernels = 'VelocityMass PressureGrad VelocityDiv'
    bcs = 'flux_boundaries'
  []
[]

(framework/include/mfem/weakforms/MFEMEigenproblemWeakForm.h)

// This file is part of the MOOSE framework
// https://mooseframework.inl.gov
//
// All rights reserved, see COPYRIGHT for full restrictions
// https://github.com/idaholab/moose/blob/master/COPYRIGHT
//
// Licensed under LGPL 2.1, please see LICENSE for details
// https://www.gnu.org/licenses/lgpl-2.1.html

#ifdef MOOSE_MFEM_ENABLED

#pragma once

#include "MFEMWeakForm.h"

/**
 * Constructs and stores a Moose::MFEM::EigenproblemEquationSystem object.
 */
class MFEMEigenproblemWeakForm : public MFEMWeakForm
{
public:
  static InputParameters validParams();

  MFEMEigenproblemWeakForm(const InputParameters & parameters);

protected:
  virtual std::shared_ptr<Moose::MFEM::EquationSystem> makeEquationSystem() override;
};

#endif

(framework/include/mfem/weakforms/MFEMTimeDependentWeakForm.h)

// This file is part of the MOOSE framework
// https://mooseframework.inl.gov
//
// All rights reserved, see COPYRIGHT for full restrictions
// https://github.com/idaholab/moose/blob/master/COPYRIGHT
//
// Licensed under LGPL 2.1, please see LICENSE for details
// https://www.gnu.org/licenses/lgpl-2.1.html

#ifdef MOOSE_MFEM_ENABLED

#pragma once

#include "MFEMWeakForm.h"

/**
 * Constructs and stores a Moose::MFEM::TimeDependentEquationSystem object.
 */
class MFEMTimeDependentWeakForm : public MFEMWeakForm
{
public:
  static InputParameters validParams();

  MFEMTimeDependentWeakForm(const InputParameters & parameters);

protected:
  virtual std::shared_ptr<Moose::MFEM::EquationSystem> makeEquationSystem() override;
};

#endif

Overview
Example Input File Syntax
Input Parameters
Input Files
Child Objects

MFEMWeakForm

Overview

Example Input File Syntax

Input Parameters

Optional Parameters

Advanced Parameters

Input Files

Child Objects

(test/tests/mfem/weakforms/steady_weakform.i)

(test/tests/mfem/weakforms/real_weakform_complex_problem.i)

(test/tests/mfem/weakforms/unknown_kernel.i)

(test/tests/mfem/weakforms/named_weakform.i)

(test/tests/mfem/weakforms/ambiguous_weakform.i)

(test/tests/mfem/weakforms/unknown_bc.i)

(test/tests/mfem/problemcomposers/two_problem_composers.i)

(test/tests/mfem/weakforms/unknown_weakform.i)

(test/tests/mfem/weakforms/steady_weakform.i)

(framework/include/mfem/weakforms/MFEMEigenproblemWeakForm.h)

(framework/include/mfem/weakforms/MFEMTimeDependentWeakForm.h)