FDTD: Real Literals and Formatting (#736)

Clean up `amrex::Real` literals (aka "numbers"). This avoids
calculating a line in double precision and casting it down to
`Real` on assignment.

Also fixes some formatting issues.

(Commit credited to Remi.)

Co-authored-by: Axel Huebl <axel.huebl@plasma.ninja>

Co-authored-by: Remi Lehe <remi.lehe@normalesup.org>

1 files changed, 36 insertions, 29 deletions

diff --git a/Source/FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/CartesianNodalAlgorithm.H b/Source/FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/CartesianNodalAlgorithm.H
index 69622c5fe..a8d95ee74 100644
--- a/Source/FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/CartesianNodalAlgorithm.H
+++ b/Source/FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/CartesianNodalAlgorithm.H
@@ -12,6 +12,8 @@
 #include <AMReX_Array4.H>
 #include <AMReX_Gpu.H>
 
+#include <array>
+
 /**
  * This struct contains only static functions to initialize the stencil coefficients
  * and to compute finite-difference derivatives for the Cartesian nodal algorithm.
@@ -24,33 +26,36 @@ struct CartesianNodalAlgorithm {
         amrex::Gpu::ManagedVector<amrex::Real>& stencil_coefs_y,
         amrex::Gpu::ManagedVector<amrex::Real>& stencil_coefs_z ) {
 
+        using namespace amrex;
+
         // Store the inverse cell size along each direction in the coefficients
         stencil_coefs_x.resize(1);
-        stencil_coefs_x[0] = 1./cell_size[0];
+        stencil_coefs_x[0] = 1._rt/cell_size[0];
         stencil_coefs_y.resize(1);
-        stencil_coefs_y[0] = 1./cell_size[1];
+        stencil_coefs_y[0] = 1._rt/cell_size[1];
         stencil_coefs_z.resize(1);
-        stencil_coefs_z[0] = 1./cell_size[2];
+        stencil_coefs_z[0] = 1._rt/cell_size[2];
     }
 
     /**
-    /* Perform derivative along x
-    /* (For a solver on a staggered grid, `UpwardDx` and `DownwardDx` take into
-    /* account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
+     * Perform derivative along x
+     * (For a solver on a staggered grid, `UpwardDx` and `DownwardDx` take into
+     * account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
     static amrex::Real UpwardDx (
         amrex::Array4<amrex::Real> const& F,
         amrex::Real const * const coefs_x, int const n_coefs_x,
         int const i, int const j, int const k ) {
 
-        amrex::Real const inv_dx = coefs_x[0];
-        return 0.5*inv_dx*( F(i+1,j,k) - F(i-1,j,k) );
+        using namespace amrex;
+        Real const inv_dx = coefs_x[0];
+        return 0.5_rt*inv_dx*( F(i+1,j,k) - F(i-1,j,k) );
     };
 
     /**
-    /* Perform derivative along x
-    /* (For a solver on a staggered grid, `UpwardDx` and `DownwardDx` take into
-    /* account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
+     * Perform derivative along x
+     * (For a solver on a staggered grid, `UpwardDx` and `DownwardDx` take into
+     * account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
     static amrex::Real DownwardDx (
         amrex::Array4<amrex::Real> const& F,
@@ -62,27 +67,28 @@ struct CartesianNodalAlgorithm {
     };
 
     /**
-    /* Perform derivative along y
-    /* (For a solver on a staggered grid, `UpwardDy` and `DownwardDy` take into
-    /* account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
+     * Perform derivative along y
+     * (For a solver on a staggered grid, `UpwardDy` and `DownwardDy` take into
+     * account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
     static amrex::Real UpwardDy (
         amrex::Array4<amrex::Real> const& F,
         amrex::Real const * const coefs_y, int const n_coefs_y,
         int const i, int const j, int const k ) {
 
+        using namespace amrex;
 #if defined WARPX_DIM_3D
-            amrex::Real const inv_dy = coefs_y[0];
-            return 0.5*inv_dy*( F(i,j+1,k) - F(i,j-1,k) );
+        Real const inv_dy = coefs_y[0];
+        return 0.5_rt*inv_dy*( F(i,j+1,k) - F(i,j-1,k) );
 #elif (defined WARPX_DIM_XZ)
-            return 0; // 2D Cartesian: derivative along y is 0
+        return 0._rt; // 2D Cartesian: derivative along y is 0
 #endif
     };
 
     /**
-    /* Perform derivative along y
-    /* (For a solver on a staggered grid, `UpwardDy` and `DownwardDy` take into
-    /* account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
+     * Perform derivative along y
+     * (For a solver on a staggered grid, `UpwardDy` and `DownwardDy` take into
+     * account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
     static amrex::Real DownwardDy (
         amrex::Array4<amrex::Real> const& F,
@@ -94,27 +100,28 @@ struct CartesianNodalAlgorithm {
     };
 
     /**
-    /* Perform derivative along z
-    /* (For a solver on a staggered grid, `UpwardDz` and `DownwardDz` take into
-    /* account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
+     * Perform derivative along z
+     * (For a solver on a staggered grid, `UpwardDz` and `DownwardDz` take into
+     * account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
     static amrex::Real UpwardDz (
         amrex::Array4<amrex::Real> const& F,
         amrex::Real const * const coefs_z, int const n_coefs_z,
         int const i, int const j, int const k ) {
 
-        amrex::Real const inv_dz = coefs_z[0];
+        using namespace amrex;
+        Real const inv_dz = coefs_z[0];
 #if defined WARPX_DIM_3D
-            return 0.5*inv_dz*( F(i,j,k+1) - F(i,j,k-1) );
+        return 0.5_rt*inv_dz*( F(i,j,k+1) - F(i,j,k-1) );
 #elif (defined WARPX_DIM_XZ)
-            return 0.5*inv_dz*( F(i,j+1,k) - F(i,j-1,k) );
+        return 0.5_rt*inv_dz*( F(i,j+1,k) - F(i,j-1,k) );
 #endif
     };
 
     /**
-    /* Perform derivative along z
-    /* (For a solver on a staggered grid, `UpwardDz` and `DownwardDz` take into
-    /* account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
+     * Perform derivative along z
+     * (For a solver on a staggered grid, `UpwardDz` and `DownwardDz` take into
+     * account the staggering; but for `CartesianNodalAlgorithm`, they are equivalent) */
     AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
     static amrex::Real DownwardDz (
         amrex::Array4<amrex::Real> const& F,