Fix PEC_insulators (#6424)

The vectors holding the parsers were not being setup correctly, leading
to out of bounds access. The fix is to add empty parsers for the fields
that are normal to the boundaries so that the vectors have the correct
length (the number of dimensions).

Also, comments were cleaned up for clarity.

Author: dpgrote

Source/BoundaryConditions/PEC_Insulator.cpp

@@ -247,24 +247,24 @@ namespace
     /* \brief Sets up the parsers, taking the input data and arranging it as needed
      *        for the loops, and compiling the parser expressions.
      *
-     * \param[in] set_field_lo      flags whether the insulator expressions were specified
-     * \param[in] set_field_hi      flags whether the insulator expressions were specified
-     * \param[in] parser_field1_lo  the parser for the first transverse field at the low boundary
-     * \param[in] parser_field2_lo  the parser for the second transverse field at the low boundary
-     * \param[in] parser_field1_hi  the parser for the first transverse field at the high boundary
-     * \param[in] parser_field2_hi  the parser for the second transverse field at the high boundary
-     * \param[out] set_fields_x_lo  the flags for the field along x at the lower boundary
-     * \param[out] set_fields_y_lo  the flags for the field along y at the lower boundary
-     * \param[out] set_fields_z_lo  the flags for the field along z at the lower boundary
-     * \param[out] set_fields_x_hi  the flags for the field along x at the upper boundary
-     * \param[out] set_fields_y_hi  the flags for the field along y at the upper boundary
-     * \param[out] set_fields_z_hi  the flags for the field along z at the upper boundary
-     * \param[out] Fx_parsers_lo    the parsers for the field along x at the lower boundary
-     * \param[out] Fy_parsers_lo    the parsers for the field along y at the lower boundary
-     * \param[out] Fz_parsers_lo    the parsers for the field along z at the lower boundary
-     * \param[out] Fx_parsers_hi    the parsers for the field along x at the upper boundary
-     * \param[out] Fy_parsers_hi    the parsers for the field along y at the upper boundary
-     * \param[out] Fz_parsers_hi    the parsers for the field along z at the upper boundary
+     * \param[in] set_field_lo      flags whether the insulator expressions were specified at the lower boundaries
+     * \param[in] set_field_hi      flags whether the insulator expressions were specified at the upper boundaries
+     * \param[in] parser_field1_lo  the parser for the first transverse field at the lower boundaries
+     * \param[in] parser_field2_lo  the parser for the second transverse field at the lower boundaries
+     * \param[in] parser_field1_hi  the parser for the first transverse field at the upper boundaries
+     * \param[in] parser_field2_hi  the parser for the second transverse field at the upper boundaries
+     * \param[out] set_fields_x_lo  the flags for the x-field at the lower boundaries
+     * \param[out] set_fields_y_lo  the flags for the y-field at the lower boundaries
+     * \param[out] set_fields_z_lo  the flags for the z-field at the lower boundaries
+     * \param[out] set_fields_x_hi  the flags for the x-field at the upper boundaries
+     * \param[out] set_fields_y_hi  the flags for the y-field at the upper boundaries
+     * \param[out] set_fields_z_hi  the flags for the z-field at the upper boundaries
+     * \param[out] Fx_parsers_lo    the parsers for the x-field at the lower boundaries
+     * \param[out] Fy_parsers_lo    the parsers for the y-field at the lower boundaries
+     * \param[out] Fz_parsers_lo    the parsers for the z-field at the lower boundaries
+     * \param[out] Fx_parsers_hi    the parsers for the x-field at the upper boundaries
+     * \param[out] Fy_parsers_hi    the parsers for the y-field at the upper boundaries
+     * \param[out] Fz_parsers_hi    the parsers for the z-field at the upper boundaries
     */
     void SetupFieldParsers(amrex::Vector<int> const & set_field_lo,
                            amrex::Vector<int> const & set_field_hi,
@@ -292,13 +292,18 @@ namespace
         set_fields_y_hi.resize(AMREX_SPACEDIM, false);
         set_fields_z_hi.resize(AMREX_SPACEDIM, false);
 
+        // For the fields normal to the boundaries, empty parsers are added to the vectors as
+        // place holders. They will not be used.
+
 #ifndef WARPX_DIM_1D_Z
         set_fields_y_lo[0] = set_field_lo[0];
         set_fields_z_lo[0] = set_field_lo[0];
         set_fields_y_hi[0] = set_field_hi[0];
         set_fields_z_hi[0] = set_field_hi[0];
+        Fx_parsers_lo.push_back(amrex::ParserExecutor<3>());
         Fy_parsers_lo.push_back(parser_field1_lo[0]->compile<3>());
         Fz_parsers_lo.push_back(parser_field2_lo[0]->compile<3>());
+        Fx_parsers_hi.push_back(amrex::ParserExecutor<3>());
         Fy_parsers_hi.push_back(parser_field1_hi[0]->compile<3>());
         Fz_parsers_hi.push_back(parser_field2_hi[0]->compile<3>());
 #endif
@@ -308,8 +313,10 @@ namespace
         set_fields_x_hi[1] = set_field_hi[1];
         set_fields_z_hi[1] = set_field_hi[1];
         Fx_parsers_lo.push_back(parser_field1_lo[1]->compile<3>());
+        Fy_parsers_lo.push_back(amrex::ParserExecutor<3>());
         Fz_parsers_lo.push_back(parser_field2_lo[1]->compile<3>());
         Fx_parsers_hi.push_back(parser_field1_hi[1]->compile<3>());
+        Fy_parsers_hi.push_back(amrex::ParserExecutor<3>());
         Fz_parsers_hi.push_back(parser_field2_hi[1]->compile<3>());
 #endif
 #if defined(WARPX_ZINDEX)
@@ -319,8 +326,10 @@ namespace
         set_fields_y_hi[WARPX_ZINDEX] = set_field_hi[WARPX_ZINDEX];
         Fx_parsers_lo.push_back(parser_field1_lo[WARPX_ZINDEX]->compile<3>());
         Fy_parsers_lo.push_back(parser_field2_lo[WARPX_ZINDEX]->compile<3>());
+        Fz_parsers_lo.push_back(amrex::ParserExecutor<3>());
         Fx_parsers_hi.push_back(parser_field1_hi[WARPX_ZINDEX]->compile<3>());
         Fy_parsers_hi.push_back(parser_field2_hi[WARPX_ZINDEX]->compile<3>());
+        Fz_parsers_hi.push_back(amrex::ParserExecutor<3>());
 #endif
     }
 
@@ -593,15 +602,9 @@ PEC_Insulator::ApplyPEC_InsulatortoField (
 
                 amrex::ParserExecutor<2> const & area_parser = ( (iside == -1) ? m_area_parsers_lo[idim] : m_area_parsers_hi[idim]);
 
-                // A special check is needed for Fx and Fz since in 1D cases no parsers will be defined for one
-                // or the other. Instead, create a dummy ParserExecutor.
-                amrex::ParserExecutor<3> const & Fx_parser = ( Fx_parsers_lo.size() > 0 ?
-                                                             ( (iside == -1) ? Fx_parsers_lo[idim] : Fx_parsers_hi[idim]) :
-                                                             amrex::ParserExecutor<3>() );
+                amrex::ParserExecutor<3> const & Fx_parser = ( (iside == -1) ? Fx_parsers_lo[idim] : Fx_parsers_hi[idim]);
                 amrex::ParserExecutor<3> const & Fy_parser = ( (iside == -1) ? Fy_parsers_lo[idim] : Fy_parsers_hi[idim]);
-                amrex::ParserExecutor<3> const & Fz_parser = ( Fz_parsers_lo.size() > 0 ?
-                                                             ( (iside == -1) ? Fz_parsers_lo[idim] : Fz_parsers_hi[idim]) :
-                                                             amrex::ParserExecutor<3>() );
+                amrex::ParserExecutor<3> const & Fz_parser = ( (iside == -1) ? Fz_parsers_lo[idim] : Fz_parsers_hi[idim]);
 
                 // loop over cells and update fields
                 amrex::ParallelFor(