Interpolate mu to B-location when computing H (#2252)

* interpolate mu to B-location when computing H

* add comments

* modify comment to reflect interpolation

* eol

* add struct to compute macroparameters at x,y,z, and util function to compute cellcoordinates

* fix eol

* remove unused variables, multifabs, and initialization of macro multifabs

* host device function

* fix typo

* doxygen comments

1 files changed, 35 insertions, 10 deletions

diff --git a/Source/FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/FieldAccessorFunctors.H b/Source/FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/FieldAccessorFunctors.H
index 0b5245228..c6cb7f9db 100644
--- a/Source/FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/FieldAccessorFunctors.H
+++ b/Source/FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/FieldAccessorFunctors.H
@@ -1,41 +1,66 @@
+/* Copyright 2020 Revathi Jambunathan
+ *
+ * This file is part of WarpX.
+ *
+ * License: BSD-3-Clause-LBNL
+ */
+
 #ifndef WARPX_FIELD_ACCESSOR_FUNCTORS_H
 #define WARPX_FIELD_ACCESSOR_FUNCTORS_H
 
 #include "WarpX.H"
+#include "Utils/CoarsenIO.H"
+#include "Utils/WarpXUtil.H"
+#include "FieldSolver/FiniteDifferenceSolver/MacroscopicProperties/MacroscopicProperties.H"
+#include <AMReX_Array.H>
 
 /**
  * \brief Functor that returns the division of the source m_field Array4 value
-          by macroparameter, m_parameter value at the respective (i,j,k,ncomp).
+          by macroparameter obtained using functor, m_getParameter,
+          at the respective (i,j,k,ncomp).
  */
+template< typename T_GetMacroparameter>
 struct FieldAccessorMacroscopic
 {
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
     FieldAccessorMacroscopic ( amrex::Array4<amrex::Real const> const a_field,
-                               amrex::Array4<amrex::Real const> const a_parameter )
-        : m_field(a_field), m_parameter(a_parameter) {}
+                               T_GetMacroparameter const& a_getParameter,
+                               amrex::GpuArray<int,3> const& a_field_stag,
+                               amrex::GpuArray<amrex::Real, AMREX_SPACEDIM> const a_domain_lo,
+                               amrex::GpuArray<amrex::Real, AMREX_SPACEDIM> const a_dx )
+        : m_field(a_field), m_getParameter(a_getParameter), m_field_stag(a_field_stag),
+          m_domain_lo(a_domain_lo), m_dx(a_dx) {}
 
     /**
-     * \brief return field value at (i,j,k,ncomp) scaled by (1/m_parameters(i,j,k,ncomp))
+     * \brief return field value at (i,j,k,ncomp) scaled by (1/m_getParameter(x,y,z))
+     *
      * \param[in] i      index along x of the Array4, m_field and m_parameter.
      * \param[in] j      index along y of the Array4, m_field and m_parameter.
      * \param[in] k      index along z of the Array4, m_field and m_parameter.
      * \param[in] ncomp  index along fourth component of the Array4, containing field-data
-                         to be returned after diving with zero-th component
-                         of m_paramter.
+                         to be returned after dividing by the macroparameter.
      *
-     * \return           m_field/m_paramter at (i,j,k,ncomp)
+     * \return           m_field/m_getParameter(x,y,z) at (i,j,k,ncomp)
      */
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
     amrex::Real operator() (int const i, int const j,
                             int const k, int const ncomp) const noexcept
     {
-        return ( m_field(i, j, k, ncomp)  /  m_parameter(i, j, k, 0) ) ;
+        amrex::Real x, y, z;
+        WarpXUtilAlgo::getCellCoordinates(i, j, k, m_field_stag, m_domain_lo, m_dx, x, y, z);
+        return ( m_field(i, j, k, ncomp)  /  m_getParameter(x, y, z) ) ;
     }
 private:
     /** Array4 of the source field to be scaled and returned by the operator() */
     amrex::Array4<amrex::Real const> const m_field;
-    /** Array4 of the macroscopic parameter used to divide m_field in the operator() */
-    amrex::Array4<amrex::Real const> const m_parameter;
+    /** Functor object to return the macroparameter at a given position on the grid.*/
+    T_GetMacroparameter const m_getParameter;
+    /** Staggering of the field multifab, m_field */
+    amrex::GpuArray<int,3> const m_field_stag;
+    /** Lower physical coordinates of the simulation domain. */
+    amrex::GpuArray<amrex::Real,AMREX_SPACEDIM> const m_domain_lo;
+    /** Cell-size array */
+    amrex::GpuArray<amrex::Real,AMREX_SPACEDIM> const m_dx;
 };