Implement div(E) diagnostics for spectral case (#720)

* Implement div(E) diagnostics for spectral case.

* split travis tests in bigger matrix

* split more TravisCI tests, add electrostatic, use defaults values

* typo

* Move computation of div(E) to base class SpectralBaseAlgorithm.

* need to split psatd too

* consistent variable names and use function to avoid duplication

* fix typo for qed tests

* typo

* also need to update run_tests.sg

* Update copyright tags.

* change matrix

* Add test of div(E) vs rho/epsilon_0 in PML test.

* SpectralFieldIndex: reuse memory slot for Bx when computing divE.

Co-authored-by: MaxThevenet <mthevenet@lbl.gov>

1 files changed, 17 insertions, 7 deletions

diff --git a/Source/FieldSolver/SpectralSolver/SpectralSolver.H b/Source/FieldSolver/SpectralSolver/SpectralSolver.H
index 6685e489c..8b33707d0 100644
--- a/Source/FieldSolver/SpectralSolver/SpectralSolver.H
+++ b/Source/FieldSolver/SpectralSolver/SpectralSolver.H
@@ -1,4 +1,4 @@
-/* Copyright 2019-2020 Maxence Thevenet, Remi Lehe
+/* Copyright 2019-2020 Maxence Thevenet, Remi Lehe, Edoardo Zoni
  *
  * This file is part of WarpX.
  *
@@ -57,14 +57,24 @@ class SpectralSolver
          */
         void pushSpectralFields();
 
+        /**
+          * \brief Public interface to call the member function ComputeSpectralDivE
+          * of the base class SpectralBaseAlgorithm from objects of class SpectralSolver
+          */
+        void ComputeSpectralDivE ( const std::array<std::unique_ptr<amrex::MultiFab>,3>& Efield,
+                                   amrex::MultiFab& divE ) {
+            algorithm->ComputeSpectralDivE( field_data, Efield, divE );
+        };
+
     private:
-        SpectralFieldData field_data; // Store field in spectral space
-                                      // and perform the Fourier transforms
+
+        // Store field in spectral space and perform the Fourier transforms
+        SpectralFieldData field_data;
+
+        // Defines field update equation in spectral space and the associated coefficients.
+        // SpectralBaseAlgorithm is a base class; this pointer is meant to point
+        // to an instance of a sub-class defining a specific algorithm
         std::unique_ptr<SpectralBaseAlgorithm> algorithm;
-        // Defines field update equation in spectral space,
-        // and the associated coefficients.
-        // SpectralBaseAlgorithm is a base class ; this pointer is meant
-        // to point an instance of a *sub-class* defining a specific algorithm
 };
 #endif // WARPX_USE_PSATD
 #endif // WARPX_SPECTRAL_SOLVER_H_