1 files changed, 98 insertions, 0 deletions
diff --git a/Source/FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/CylindricalYeeAlgorithm.H b/Source/FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/CylindricalYeeAlgorithm.H
new file mode 100644
index 000000000..5d160d865
--- /dev/null
+++ b/Source/FieldSolver/FiniteDifferenceSolver/FiniteDifferenceAlgorithms/CylindricalYeeAlgorithm.H
@@ -0,0 +1,98 @@
+#ifndef WARPX_FINITE_DIFFERENCE_ALGORITHM_CYLINDRICAL_YEE_H_
+#define WARPX_FINITE_DIFFERENCE_ALGORITHM_CYLINDRICAL_YEE_H_
+
+#include <AMReX_REAL.H>
+#include <AMReX_Array4.H>
+#include <AMReX_Gpu.H>
+
+struct CylindricalYeeAlgorithm {
+
+    static void InitializeStencilCoefficients(
+        std::array<amrex::Real,3>& cell_size,
+        amrex::Gpu::ManagedVector<amrex::Real>& stencil_coefs_r,
+        amrex::Gpu::ManagedVector<amrex::Real>& stencil_coefs_z ) {
+
+        // Store the inverse cell size along each direction in the coefficients
+        stencil_coefs_r.resize(1);
+        stencil_coefs_r[0] = 1./cell_size[0];  // 1./dr
+        stencil_coefs_z.resize(1);
+        stencil_coefs_z[0] = 1./cell_size[2];  // 1./dz
+    }
+
+    /** Applies the differential operator `1/r * d(rF)/dr`,
+     * where `F` is on a *nodal* grid in `r`
+     * and the differential operator is evaluated on *cell-centered* grid.
+     * The input parameter `r` is given at the cell-centered position*/
+    AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
+    static amrex::Real UpwardDrr_over_r(
+        amrex::Array4<amrex::Real> const& F,
+        amrex::Real const r, int const dr,
+        amrex::Real const* coefs_r, int const n_coefs_r,
+        int const i, int const j, int const k, int const comp ) {
+
+        amrex::Real inv_dr = coefs_r[0];
+        return inv_dr*( (r+0.5*dr)*F(i+1,j,k,comp) - (r-0.5*dr)*F(i,j,k,comp) );
+    };
+
+    AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
+    static amrex::Real UpwardDr(
+        amrex::Array4<amrex::Real> const& F,
+        amrex::Real const* coefs_r, int const n_coefs_r,
+        int const i, int const j, int const k, int const comp ) {
+
+        amrex::Real inv_dr = coefs_r[0];
+        return inv_dr*( F(i+1,j,k,comp) - F(i,j,k,comp) );
+    };
+
+    AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
+    static amrex::Real DownwardDr(
+        amrex::Array4<amrex::Real> const& F,
+        amrex::Real const* coefs_r, int const n_coefs_r,
+        int const i, int const j, int const k, int const comp ) {
+
+        amrex::Real inv_dr = coefs_r[0];
+        return inv_dr*( F(i,j,k,comp) - F(i-1,j,k,comp) );
+    };
+
+    AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
+    static amrex::Real UpwardDz(
+        amrex::Array4<amrex::Real> const& F,
+        amrex::Real const* coefs_z, int const n_coefs_z,
+        int const i, int const j, int const k, int const comp ) {
+
+        amrex::Real inv_dz = coefs_z[0];
+        return inv_dz*( F(i,j+1,k,comp) - F(i,j,k,comp) );
+    };
+
+    AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
+    static amrex::Real DownwardDz(
+        amrex::Array4<amrex::Real> const& F,
+        amrex::Real const* coefs_z, int const n_coefs_z,
+        int const i, int const j, int const k, int const comp ) {
+
+        amrex::Real inv_dz = coefs_z[0];
+        return inv_dz*( F(i,j,k,comp) - F(i,j-1,k,comp) );
+    };
+
+    AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE
+    static amrex::Real DivideByR(
+        amrex::Array4<amrex::Real> const& F,
+        amrex::Real const r, int const dr, int const m,
+        int const i, int const j, int const k, int const comp) {
+
+        if (r != 0) {
+            return F(i,j,k,comp)/r;
+        } else { // r==0 ; singularity when dividing by r
+            if (m==1) {
+                // For m==1, F is linear in r, for small r
+                // Therefore, the formula below regularizes the singularity
+                return F(i+1,j,k,comp)/dr;
+            } else {
+                return 0;
+            }
+        }
+    };
+
+};
+
+#endif // WARPX_FINITE_DIFFERENCE_ALGORITHM_CYLINDRICAL_YEE_H_