From 4d02241503922dafa79c0b4346a83e8d170e59e1 Mon Sep 17 00:00:00 2001
From: Daniel Schwen <daniel.schwen@inl.gov>
Date: Mon, 20 Jan 2020 13:01:02 -0700
Subject: [PATCH] Add variable shim for FFT (#401)

---
 include/variables/MooseFFTVariable.h | 153 +++++++++++++++++++++++++++
 src/variables/MooseFFTVariable.C     |  20 ++++
 2 files changed, 173 insertions(+)
 create mode 100644 include/variables/MooseFFTVariable.h
 create mode 100644 src/variables/MooseFFTVariable.C

diff --git a/include/variables/MooseFFTVariable.h b/include/variables/MooseFFTVariable.h
new file mode 100644
index 00000000..8107c32b
--- /dev/null
+++ b/include/variables/MooseFFTVariable.h
@@ -0,0 +1,153 @@
+/**********************************************************************/
+/*                     DO NOT MODIFY THIS HEADER                      */
+/* MAGPIE - Mesoscale Atomistic Glue Program for Integrated Execution */
+/*                                                                    */
+/*            Copyright 2017 Battelle Energy Alliance, LLC            */
+/*                        ALL RIGHTS RESERVED                         */
+/**********************************************************************/
+
+#pragma once
+
+#include "MooseVariable.h"
+
+class MooseFFTVariable : public MooseVariable
+{
+public:
+  static InputParameters validParams();
+
+  MooseFFTVariable(const InputParameters & parameters);
+
+  virtual bool isNodal() const { return false; }
+
+  /**
+   * Clear out the dof indices.  We do this in case this variable is not going to be prepared at
+   * all...
+   */
+  virtual void clearDofIndices() {}
+
+  /**
+   * Prepare the elemental degrees of freedom
+   */
+  virtual void prepare() {}
+
+  /**
+   * Prepare the neighbor element degrees of freedom
+   */
+  virtual void prepareNeighbor() { mooseError("Neighbor FFT variables are not supported yet."); }
+
+  /**
+   * Prepare a lower dimensional element's degrees of freedom
+   */
+  virtual void prepareLowerD()
+  {
+    mooseError("Lower dimensional FFT variables are not supported yet.");
+  }
+
+  virtual void prepareAux() {}
+
+  virtual void reinitNode() {}
+  virtual void reinitAux() {}
+  virtual void reinitAuxNeighbor() { mooseError("Neighbor FFT variables are not supported yet."); }
+
+  virtual void reinitNodes(const std::vector<dof_id_type> &)
+  {
+    mooseError("Nodal FFT variables are not supported.");
+  }
+  virtual void reinitNodesNeighbor(const std::vector<dof_id_type> & nodes)
+  {
+    mooseError("Nodal FFT variables are not supported.");
+  }
+
+  /**
+   * Field type of this variable
+   */
+  virtual Moose::VarFieldType fieldType() const { return Moose::VarFieldType::VAR_FIELD_STANDARD; }
+
+  /**
+   * @returns true if this is a vector-valued element, false otherwise.
+   */
+  virtual bool isVector() const { return false; };
+
+  /**
+   * Is this variable defined at nodes
+   * @return true if it the variable is defined at nodes, otherwise false
+   */
+  virtual bool isNodalDefined() const { return false; }
+
+  virtual const dof_id_type & nodalDofIndex() const
+  {
+    mooseError("Nodal FFT variables are not supported.");
+  }
+
+  virtual const dof_id_type & nodalDofIndexNeighbor() const
+  {
+    mooseError("Nodal FFT variables are not supported.");
+  }
+
+  /**
+   * Current element this variable is evaluated at
+   */
+  virtual const Elem * const & currentElem() const
+  {
+    mooseError("Current element access not supported.");
+  }
+
+  /**
+   * The subdomains the variable is active on
+   */
+  virtual const std::set<SubdomainID> & activeSubdomains() const { return _all_subdomains; }
+  /**
+   * Is the variable active on the subdomain?
+   * @param subdomain The subdomain id in question
+   * @return true if active on subdomain, false otherwise
+   */
+  virtual bool activeOnSubdomain(SubdomainID subdomain) const { return true; }
+
+  /**
+   * Prepare the initial condition
+   */
+  virtual void prepareIC() {}
+
+  /**
+   * Compute values at interior quadrature points
+   */
+  virtual void computeElemValues()
+  { // meat!
+  }
+
+  /**
+   * Compute values at facial quadrature points
+   */
+  virtual void computeElemValuesFace() {}
+  /**
+   * Compute values at facial quadrature points for the neighbor
+   */
+  virtual void computeNeighborValuesFace() {}
+  /**
+   * Compute values at quadrature points for the neighbor
+   */
+  virtual void computeNeighborValues() {}
+  /**
+   * compute values at quadrature points on the lower dimensional element
+   */
+  virtual void computeLowerDValues() {}
+  /**
+   * Compute nodal values of this variable in the neighbor
+   */
+  virtual void computeNodalNeighborValues() {}
+  /**
+   * Compute nodal values of this variable
+   */
+  virtual void computeNodalValues() {}
+
+  virtual void getDofIndices(const Elem * elem, std::vector<dof_id_type> & dof_indices) const {}
+
+  virtual unsigned int numberOfDofsNeighbor() { return 0; }
+
+  virtual void insert(NumericVector<Number> & residual) {}
+  virtual void add(NumericVector<Number> & residual) {}
+
+protected:
+  std::vector<dof_id_type> _no_dofs;
+  std::set<SubdomainID> _all_subdomains;
+};
diff --git a/src/variables/MooseFFTVariable.C b/src/variables/MooseFFTVariable.C
new file mode 100644
index 00000000..eedf1db4
--- /dev/null
+++ b/src/variables/MooseFFTVariable.C
@@ -0,0 +1,20 @@
+/**********************************************************************/
+/*                     DO NOT MODIFY THIS HEADER                      */
+/* MAGPIE - Mesoscale Atomistic Glue Program for Integrated Execution */
+/*                                                                    */
+/*            Copyright 2017 Battelle Energy Alliance, LLC            */
+/*                        ALL RIGHTS RESERVED                         */
+/**********************************************************************/
+
+#include <MooseFFTVariable.h>
+
+InputParameters
+MooseFFTVariable::validParams()
+{
+  InputParameters params = MooseVariableFEBase::validParams();
+  return params;
+}
+
+MooseFFTVariable::MooseFFTVariable(const InputParameters & parameters) : MooseVariable(parameters)
+{
+}