1 files changed, 71 insertions, 3 deletions

diff --git a/Source/WarpX.H b/Source/WarpX.H
index decde3dc2..3bab73833 100644
--- a/Source/WarpX.H
+++ b/Source/WarpX.H
@@ -24,6 +24,7 @@
 #include <AMReX_LayoutData.H>
 #include <AMReX_Interpolater.H>
 #include <AMReX_FillPatchUtil.H>
+#include <WarpXParserWrapper.H>
 
 #ifdef _OPENMP
 #   include <omp.h>
@@ -73,8 +74,10 @@ public:
 
     MultiParticleContainer& GetPartContainer () { return *mypc; }
 
-    static void shiftMF(amrex::MultiFab& mf, const amrex::Geometry& geom, int num_shift, int dir,
-                        amrex::Real external_field = 0.);
+    static void shiftMF (amrex::MultiFab& mf, const amrex::Geometry& geom,
+                         int num_shift, int dir, amrex::Real external_field=0.0,
+                         bool useparser = false,
+                         ParserWrapper *field_parser=nullptr);
 
     static void GotoNextLine (std::istream& is);
 
@@ -86,6 +89,28 @@ public:
     static amrex::Vector<amrex::Real> E_external_grid;
     static amrex::Vector<amrex::Real> B_external_grid;
 
+    // Initialization Type for External E and B
+    static std::string B_ext_grid_s;
+    static std::string E_ext_grid_s;
+
+    // Parser for B_external on the grid
+    static std::string str_Bx_ext_grid_function;
+    static std::string str_By_ext_grid_function;
+    static std::string str_Bz_ext_grid_function;
+    // Parser for E_external on the grid
+    static std::string str_Ex_ext_grid_function;
+    static std::string str_Ey_ext_grid_function;
+    static std::string str_Ez_ext_grid_function;
+
+    // ParserWrapper for B_external on the grid
+    std::unique_ptr<ParserWrapper> Bxfield_parser;
+    std::unique_ptr<ParserWrapper> Byfield_parser;
+    std::unique_ptr<ParserWrapper> Bzfield_parser;
+    // ParserWrapper for E_external on the grid
+    std::unique_ptr<ParserWrapper> Exfield_parser;
+    std::unique_ptr<ParserWrapper> Eyfield_parser;
+    std::unique_ptr<ParserWrapper> Ezfield_parser;
+
     // Algorithms
     static long current_deposition_algo;
     static long charge_deposition_algo;
@@ -323,6 +348,49 @@ public:
 
 protected:
 
+    /**
+     * \brief
+     *  This function initializes E, B, rho, and F, at all the levels
+     *  of the multifab. rho and F are initialized with 0.
+     *  The E and B fields are initialized using user-defined inputs.
+     *  The initialization type is set using "B_ext_grid_init_style"
+     *  and "E_ext_grid_init_style". The initialization style is set to "default"
+     *  if not explicitly defined by the user, and the E and B fields are
+     *  initialized with E_external_grid and B_external_grid, respectively, each with
+     *  a default value of 0.
+     *  If the initialization type for the E and B field is "constant",
+     *  then, the E and B fields at all the levels are initialized with
+     *  user-defined values for E_external_grid and B_external_grid.
+     *  If the initialization type for B-field is set to
+     *  "parse_B_ext_grid_function", then, the parser is used to read
+     *  Bx_external_grid_function(x,y,z), By_external_grid_function(x,y,z),
+     *  and Bz_external_grid_function(x,y,z).
+     *  Similarly, if the E-field initialization type is set to
+     *  "parse_E_ext_grid_function", then, the parser is used to read
+     *  Ex_external_grid_function(x,y,z), Ey_external_grid_function(x,y,z),
+     *  and Ex_external_grid_function(x,y,z). The parser for the E and B
+     *  initialization assumes that the function has three independent
+     *  variables, at max, namely, x, y, z. However, any number of constants
+     *  can be used in the function used to define the E and B fields on the grid.
+     */
+    void InitLevelData (int lev, amrex::Real time);
+
+    /**
+     * \brief
+     * This function initializes the E and B fields on each level
+     * using the parser and the user-defined function for the external fields.
+     * The subroutine will parse the x_/y_z_external_grid_function and
+     * then, the B or E multifab is initialized based on the (x,y,z) position
+     * on the staggered yee-grid or cell-centered grid.
+     */
+    void InitializeExternalFieldsOnGridUsingParser (
+         amrex::MultiFab *mfx, amrex::MultiFab *mfy, amrex::MultiFab *mfz,
+         ParserWrapper *xfield_parser, ParserWrapper *yfield_parser,
+         ParserWrapper *zfield_parser, amrex::IntVect x_nodal_flag,
+         amrex::IntVect y_nodal_flag, amrex::IntVect z_nodal_flag,
+         const int lev);
+
+
     //! Tagging cells for refinement
     virtual void ErrorEst (int lev, amrex::TagBoxArray& tags, amrex::Real time, int /*ngrow*/) final;
 
@@ -410,7 +478,6 @@ private:
 
     void AllocLevelData (int lev, const amrex::BoxArray& new_grids,
                          const amrex::DistributionMapping& new_dmap);
-    void InitLevelData (int lev, amrex::Real time);
 
     void InitFromCheckpoint ();
     void PostRestart ();
@@ -665,4 +732,5 @@ private:
     int insitu_pin_mesh;
 };
 
+
 #endif