Add divergence and gradient auxkernels

include/auxkernels/MFEMCurlAux.h

@@ -3,7 +3,7 @@
 #include "MFEMAuxKernel.h"
 
 /*
-Class to set an auxvariable to be the curl of a variable.
+Class to set an H(div) auxvariable to be the curl of a H(curl) vector variable.
 */
 class MFEMCurlAux : public MFEMAuxKernel
 {
@@ -18,7 +18,7 @@ class MFEMCurlAux : public MFEMAuxKernel
   virtual void execute() override;
 
 protected:
-  // Name of auxvariable to store the result of the auxkernel in.
+  // Name of source MFEMVariable to take the curl of.
   VariableName _source_var_name;
   // Pointer to source gridfunction.
   mfem::ParGridFunction & _source_var;

include/auxkernels/MFEMDivAux.h

@@ -0,0 +1,30 @@
+#pragma once
+#include "../common/pfem_extras.hpp"
+#include "MFEMAuxKernel.h"
+
+/*
+Class to set an L2 auxvariable to be the divergence of a H(div) vector variable.
+*/
+class MFEMDivAux : public MFEMAuxKernel
+{
+public:
+  static InputParameters validParams();
+
+  MFEMDivAux(const InputParameters & parameters);
+
+  virtual ~MFEMDivAux() = default;
+
+  // Computes the auxvariable.
+  virtual void execute() override;
+
+protected:
+  // Name of source MFEMVariable to take the divergence of.
+  VariableName _source_var_name;
+  // Pointer to source gridfunction.
+  mfem::ParGridFunction & _source_var;
+  // FESpaces
+  mfem::ParFiniteElementSpace & _hdiv_fespace;
+  mfem::ParFiniteElementSpace & _l2_fespace;
+  // Divergence operator
+  mfem::common::ParDiscreteCurlOperator _div;
+};

include/auxkernels/MFEMGradAux.h

@@ -0,0 +1,30 @@
+#pragma once
+#include "../common/pfem_extras.hpp"
+#include "MFEMAuxKernel.h"
+
+/*
+Class to set an H(curl) auxvariable to be the gradient of a H1 scalar variable.
+*/
+class MFEMGradAux : public MFEMAuxKernel
+{
+public:
+  static InputParameters validParams();
+
+  MFEMGradAux(const InputParameters & parameters);
+
+  virtual ~MFEMGradAux() = default;
+
+  // Computes the auxvariable.
+  virtual void execute() override;
+
+protected:
+  // Name of source MFEMVariable to take the gradient of.
+  VariableName _source_var_name;
+  // Pointer to source gridfunction.
+  mfem::ParGridFunction & _source_var;
+  // FESpaces
+  mfem::ParFiniteElementSpace & _h1_fespace;
+  mfem::ParFiniteElementSpace & _hcurl_fespace;
+  // Grad operator
+  mfem::common::ParDiscreteGradOperator _grad;
+};

src/auxkernels/MFEMCurlAux.C

@@ -4,7 +4,7 @@
 registerMooseObject("PlatypusApp", MFEMCurlAux);
 
 /*
-Class to set an auxvariable to be the curl of a variable.
+Class to set an H(div) auxvariable to be the curl of a H(curl) vector variable.
 */
 InputParameters
 MFEMCurlAux::validParams()

src/auxkernels/MFEMDivAux.C

@@ -0,0 +1,35 @@
+#pragma once
+#include "MFEMDivAux.h"
+
+registerMooseObject("PlatypusApp", MFEMDivAux);
+
+/*
+Class to set an L2 auxvariable to be the divergence of a H(div) vector variable.
+*/
+InputParameters
+MFEMDivAux::validParams()
+{
+  InputParameters params = MFEMAuxKernel::validParams();
+  params.addRequiredParam<VariableName>("source",
+                                        "Vector H(div) MFEMVariable to take the divergence of.");
+  return params;
+}
+
+MFEMDivAux::MFEMDivAux(const InputParameters & parameters)
+  : MFEMAuxKernel(parameters),
+    _source_var_name(getParam<VariableName>("source")),
+    _source_var(*getMFEMProblem().getProblemData()._gridfunctions.Get(_source_var_name)),
+    _hdiv_fespace(*_source_var.ParFESpace()),
+    _l2_fespace(*_result_var.ParFESpace()),
+    _div(&_hdiv_fespace, &_l2_fespace)
+{
+  _div.Assemble();
+  _div.Finalize();
+}
+
+// Computes the auxvariable.
+void
+MFEMDivAux::execute()
+{
+  _div.Mult(_source_var, _result_var);
+}

src/auxkernels/MFEMGradAux.C

@@ -0,0 +1,35 @@
+#pragma once
+#include "MFEMGradAux.h"
+
+registerMooseObject("PlatypusApp", MFEMGradAux);
+
+/*
+Class to set an H(curl) auxvariable to be the gradient of a H1 scalar variable.
+*/
+InputParameters
+MFEMGradAux::validParams()
+{
+  InputParameters params = MFEMAuxKernel::validParams();
+  params.addRequiredParam<VariableName>("source",
+                                        "Scalar H1 MFEMVariable to take the gradient of.");
+  return params;
+}
+
+MFEMGradAux::MFEMGradAux(const InputParameters & parameters)
+  : MFEMAuxKernel(parameters),
+    _source_var_name(getParam<VariableName>("source")),
+    _source_var(*getMFEMProblem().getProblemData()._gridfunctions.Get(_source_var_name)),
+    _h1_fespace(*_source_var.ParFESpace()),
+    _hcurl_fespace(*_result_var.ParFESpace()),
+    _grad(&_h1_fespace, &_hcurl_fespace)
+{
+  _grad.Assemble();
+  _grad.Finalize();
+}
+
+// Computes the auxvariable.
+void
+MFEMGradAux::execute()
+{
+  _grad.Mult(_source_var, _result_var);
+}