Cleanup + add comments

2 files changed, 36 insertions, 13 deletions

diff --git a/Source/FieldSolver/SpectralSolver/SpectralSolver.H b/Source/FieldSolver/SpectralSolver/SpectralSolver.H
index 363ac7bd8..9870cbfb5 100644
--- a/Source/FieldSolver/SpectralSolver/SpectralSolver.H
+++ b/Source/FieldSolver/SpectralSolver/SpectralSolver.H
@@ -5,8 +5,11 @@
 #include <PsatdAlgorithm.H>
 #include <SpectralFieldData.H>
 
-/* \brief
- * TODO
+/* \brief Top-level class for the electromagnetic spectral solver
+ *
+ * Stores the field in spectral space, and has member functions
+ * to Fourier-transform the fields between real space and spectral space
+ * and to update fields in spectral space over one time step.
  */
 class SpectralSolver
 {
@@ -16,28 +19,47 @@ class SpectralSolver
         PsatdAlgorithm algorithm; // Contains Psatd coefficients
                                   // and field update equation
     public:
+        // Inline definition of the member functions of `SpectralSolver`
+        // The body of these functions is short, since the work is done in the
+        // underlying classes `SpectralFieldData` and `PsatdAlgorithm`
+
+        /* \brief Initialize the spectral solver */
         SpectralSolver( const amrex::BoxArray& realspace_ba,
                         const amrex::DistributionMapping& dm,
-                        const int norder_x, const int norder_y, const int norder_z,
-                        const bool nodal, const amrex::RealVect dx, const amrex::Real dt )
-        {
+                        const int norder_x, const int norder_y,
+                        const int norder_z, const bool nodal,
+                        const amrex::RealVect dx, const amrex::Real dt ) {
             // Initialize all structures using the same distribution mapping dm
-            // - Initialize k space (Contains size of each box in spectral space,
-            // and corresponding values of the k vectors)
-            const SpectralKSpace k_space = SpectralKSpace( realspace_ba, dm, dx );
-            // - Initialize algorithm (coefficients) over this space
-            algorithm = PsatdAlgorithm( k_space, dm, norder_x, norder_y, norder_z, nodal, dt );
+
+            // - Initialize k space object (Contains info about the size of
+            // the spectral space corresponding to each box in `realspace_ba`,
+            // as well as the value of the corresponding k coordinates)
+            const SpectralKSpace k_space= SpectralKSpace(realspace_ba, dm, dx);
+            // - Initialize the algorithm (coefficients) over this space
+            algorithm = PsatdAlgorithm( k_space, dm, norder_x, norder_y,
+                                        norder_z, nodal, dt );
             // - Initialize arrays for fields in Fourier space + FFT plans
             field_data = SpectralFieldData( realspace_ba, k_space, dm );
         };
+
+        /* \brief Transform the component `i_comp` of MultiFab `mf`
+         *  to spectral space, and store the corresponding result internally
+         *  (in the spectral field specified by `field_index`) */
         void ForwardTransform( const amrex::MultiFab& mf,
-                               const int field_index, const int i_comp=0 ){
+                               const int field_index,
+                               const int i_comp=0 ){
             field_data.ForwardTransform( mf, field_index, i_comp );
         };
+
+        /* \brief Transform spectral field specified by `field_index` back to
+         * real space, and store it in the component `i_comp` of `mf` */
         void BackwardTransform( amrex::MultiFab& mf,
-                                const int field_index, const int i_comp=0 ){
+                                const int field_index,
+                                const int i_comp=0 ){
             field_data.BackwardTransform( mf, field_index, i_comp );
         };
+
+        /* \brief Update the fields in spectral space, over one timestep */
         void pushSpectralFields(){
             algorithm.pushSpectralFields( field_data );
         };
diff --git a/Source/FieldSolver/SpectralSolver/WarpX_Complex.H b/Source/FieldSolver/SpectralSolver/WarpX_Complex.H
index 8e2b3977f..c898c5baa 100644
--- a/Source/FieldSolver/SpectralSolver/WarpX_Complex.H
+++ b/Source/FieldSolver/SpectralSolver/WarpX_Complex.H
@@ -21,6 +21,7 @@ static_assert( sizeof(Complex) == sizeof(fftw_complex),
     "The complex types in WarpX and FFTW do not match.");
 
 #endif
-static_assert(sizeof(Complex) == sizeof(amrex::Real[2]), "Unexpected complex type.");
+static_assert(sizeof(Complex) == sizeof(amrex::Real[2]),
+              "Unexpected complex type.");
 
 #endif //WARPX_COMPLEX_H_