move field sover condition check to field solver

- remove static assert from `gridConfig.unitless`
- add condition check for `DirectionalSplitting`
- move Courant Firedrich Levy condition to `YeeSolver` and `NoSolver`

Author: psychocoderHPC

src/picongpu/include/fields/MaxwellSolver/DirSplitting/DirSplitting.hpp

@@ -40,7 +40,34 @@ namespace dirSplitting
 {
 using namespace PMacc;
 
-class DirSplitting
+/** Check Directional Splitting grid and time conditions
+ *
+ * This is a workaround that the condition check is only
+ * triggered if the current used solver is `DirSplitting`
+ */
+template<typename T_UsedSolver, typename T_Dummy=void>
+struct ConditionCheck
+{
+};
+
+template<typename T_Dummy>
+struct ConditionCheck<DirSplitting, T_Dummy>
+{
+    /* Directional Splitting conditions:
+     *
+     * using SI units to avoid round off errors
+     */
+    PMACC_CASSERT_MSG(DirectionSplitting_Set_dX_equal_dt_times_c____check_your_gridConfig_param_file,
+                      (SI::SPEED_OF_LIGHT_SI * SI::DELTA_T_SI) == SI::CELL_WIDTH_SI);
+    PMACC_CASSERT_MSG(DirectionSplitting_use_cubic_cells____check_your_gridConfig_param_file,
+                      SI::CELL_HEIGHT_SI == SI::CELL_WIDTH_SI);
+#if (SIMDIM == DIM3)
+    PMACC_CASSERT_MSG(DirectionSplitting_use_cubic_cells____check_your_gridConfig_param_file,
+                      SI::CELL_DEPTH_SI == SI::CELL_WIDTH_SI);
+#endif
+};
+
+class DirSplitting : private ConditionCheck<fieldSolver::FieldSolver>
 {
 private:
     template<typename CursorE, typename CursorB, typename GridSize>

src/picongpu/include/fields/MaxwellSolver/None/NoSolver.hpp

@@ -34,26 +34,31 @@ namespace picongpu
     {
         using namespace PMacc;
 
+        /** Check Yee grid and time conditions
+         *
+         * This is a workaround that the condition check is only
+         * triggered if the current used solver is `NoSolver`
+         */
+        template<typename T_UsedSolver, typename T_Dummy=void>
+        struct ConditionCheck
+        {
+        };
+
+        template<typename T_Dummy>
+        struct ConditionCheck<NoSolver, T_Dummy>
+        {
+            /* Courant-Friedrichs-Levy-Condition for Yee Field Solver: */
+            PMACC_CASSERT_MSG(Courant_Friedrichs_Levy_condition_failure____check_your_gridConfig_param_file,
+                (SPEED_OF_LIGHT*SPEED_OF_LIGHT*DELTA_T*DELTA_T*INV_CELL2_SUM)<=1.0);
+        };
 
-        class NoSolver
+        class NoSolver : private ConditionCheck<fieldSolver::FieldSolver>
         {
         private:
             typedef MappingDesc::SuperCellSize SuperCellSize;
 
             MappingDesc cellDescription;
 
-            template<uint32_t AREA>
-            void updateE()
-            {
-                return;
-            }
-
-            template<uint32_t AREA>
-            void updateBHalf()
-            {
-                return;
-            }
-
         public:
 
             NoSolver(MappingDesc cellDescription) : cellDescription(cellDescription)

src/picongpu/include/fields/MaxwellSolver/Yee/YeeSolver.hpp

@@ -57,13 +57,18 @@ class YeeSolver
 private:
     typedef MappingDesc::SuperCellSize SuperCellSize;
 
+
     FieldE* fieldE;
     FieldB* fieldB;
     MappingDesc cellDescription;
 
     template<uint32_t AREA>
     void updateE()
     {
+        /* Courant-Friedrichs-Levy-Condition for Yee Field Solver: */
+        PMACC_CASSERT_MSG(Courant_Friedrichs_Levy_condition_failure____check_your_gridConfig_param_file,
+            (SPEED_OF_LIGHT*SPEED_OF_LIGHT*DELTA_T*DELTA_T*INV_CELL2_SUM)<=1.0);
+        
         typedef SuperCellDescription<
                 SuperCellSize,
                 typename CurlB::LowerMargin,

src/picongpu/include/simulation_defines/unitless/gridConfig.unitless

@@ -47,8 +47,4 @@ namespace picongpu
     const float_X INV_CELL2_SUM = 1.0 / ( CELL_WIDTH  * CELL_WIDTH  );
 #endif
 
-    /* Courant-Friedrichs-Levy-Condition for Yee Field Solver: */
-    PMACC_CASSERT_MSG(Courant_Friedrichs_Levy_condition_failure____check_your_gridConfig_param_file,
-                     (SPEED_OF_LIGHT*SPEED_OF_LIGHT*DELTA_T*DELTA_T*INV_CELL2_SUM)<=1.0);
-
 }