From b0fa728137e1687eac02354e49741c7edaa24aae Mon Sep 17 00:00:00 2001
From: Daniel Schwen <daniel@schwen.de>
Date: Mon, 20 Jan 2020 18:36:06 -0700
Subject: [PATCH] Add aux kernel to read buffer content (#401)

---
 include/auxkernels/FFTBufferAux.h | 32 ++++++++++++++++++++++++++++++
 src/auxkernels/FFTBufferAux.C     | 33 +++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)
 create mode 100644 include/auxkernels/FFTBufferAux.h
 create mode 100644 src/auxkernels/FFTBufferAux.C

diff --git a/include/auxkernels/FFTBufferAux.h b/include/auxkernels/FFTBufferAux.h
new file mode 100644
index 00000000..b78ecf95
--- /dev/null
+++ b/include/auxkernels/FFTBufferAux.h
@@ -0,0 +1,32 @@
+/**********************************************************************/
+/*                     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 "AuxKernel.h"
+
+class FFTBufferAux;
+template <typename T>
+class FFTBufferBase;
+
+template <>
+InputParameters validParams<FFTBufferAux>();
+
+/**
+ *
+ */
+class FFTBufferAux : public AuxKernel
+{
+public:
+  FFTBufferAux(const InputParameters & parameters);
+
+protected:
+  virtual Real computeValue() override;
+
+  const FFTBufferBase<Real> & _buffer;
+};
diff --git a/src/auxkernels/FFTBufferAux.C b/src/auxkernels/FFTBufferAux.C
new file mode 100644
index 00000000..5207a2d5
--- /dev/null
+++ b/src/auxkernels/FFTBufferAux.C
@@ -0,0 +1,33 @@
+/**********************************************************************/
+/*                     DO NOT MODIFY THIS HEADER                      */
+/* MAGPIE - Mesoscale Atomistic Glue Program for Integrated Execution */
+/*                                                                    */
+/*            Copyright 2017 Battelle Energy Alliance, LLC            */
+/*                        ALL RIGHTS RESERVED                         */
+/**********************************************************************/
+
+#include "FFTBufferAux.h"
+#include "FFTBufferBase.h"
+
+registerMooseObject("MagpieApp", FFTBufferAux);
+
+template <>
+InputParameters
+validParams<FFTBufferAux>()
+{
+  InputParameters params = validParams<AuxKernel>();
+  params.addClassDescription("Fetch values from an FFT buffer.");
+  params.addRequiredParam<UserObjectName>("fft_buffer", "Real valued FFT buffer object");
+  return params;
+}
+
+FFTBufferAux::FFTBufferAux(const InputParameters & parameters)
+  : AuxKernel(parameters), _buffer(getUserObject<FFTBufferBase<Real>>("fft_buffer"))
+{
+}
+
+Real
+FFTBufferAux::computeValue()
+{
+  return _buffer(_current_elem->centroid());
+}