Simplify overwrite_amrex_parser_defaults WarpXAMReXInit.cpp (ECP-Warp…

…X#4965)

* simplify WarpXAMReXInit.cpp

* correct some typos

* remove space

Source/Initialization/WarpXAMReXInit.cpp

@@ -17,66 +17,93 @@
 #include <string>
 
 namespace {
-    /** Overwrite defaults in AMReX Inputs
-     *
-     * This overwrites defaults in amrex::ParmParse for inputs.
-     */
-    void
-    overwrite_amrex_parser_defaults ()
-    {
-        amrex::ParmParse pp_amrex("amrex");
 
+#ifdef AMREX_USE_GPU
+        constexpr auto amrex_use_gpu = true;
+#else
+        constexpr auto amrex_use_gpu = false;
+#endif
+
+    void override_default_abort_on_out_of_gpu_memory ()
+    {
         // https://amrex-codes.github.io/amrex/docs_html/GPU.html#inputs-parameters
-        bool abort_on_out_of_gpu_memory = true; // AMReX' default: false
+        auto pp_amrex = amrex::ParmParse{"amrex"};
+        bool abort_on_out_of_gpu_memory = true; // AMReX's default: false
         pp_amrex.queryAdd("abort_on_out_of_gpu_memory", abort_on_out_of_gpu_memory);
+    }
 
-        bool the_arena_is_managed = false; // AMReX' default: true
+    void override_default_the_arena_is_managed ()
+    {
+        auto pp_amrex = amrex::ParmParse{"amrex"};
+        bool the_arena_is_managed = false; // AMReX's default: true
         pp_amrex.queryAdd("the_arena_is_managed", the_arena_is_managed);
+    }
 
+    void override_default_omp_threads ()
+    {
         // https://amrex-codes.github.io/amrex/docs_html/InputsComputeBackends.html
-        std::string omp_threads = "nosmt"; // AMReX' default: system
+        auto pp_amrex = amrex::ParmParse{"amrex"};
+        std::string omp_threads = "nosmt"; // AMReX's default: system
         pp_amrex.queryAdd("omp_threads", omp_threads);
+    }
+
+    void set_device_synchronization ()
+    {
+        //See https://github.com/AMReX-Codes/amrex/pull/3763
+        auto warpx_do_device_synchronize = amrex_use_gpu;
+
+        auto pp_warpx = amrex::ParmParse{"warpx"};
+        pp_warpx.query("do_device_synchronize", warpx_do_device_synchronize);
+        bool do_device_synchronize = warpx_do_device_synchronize;
+
+        auto pp_tiny_profiler = amrex::ParmParse{"tiny_profiler"};
+        if (pp_tiny_profiler.queryAdd("device_synchronize_around_region", do_device_synchronize) )
+        {
+            WARPX_ALWAYS_ASSERT_WITH_MESSAGE(
+                do_device_synchronize == warpx_do_device_synchronize,
+                "tiny_profiler.device_synchronize_around_region overrides warpx.do_device_synchronize.");
+        }
+
+    }
 
+    void apply_workaround_for_warpx_numprocs ()
+    {
         // Work-around:
         // If warpx.numprocs is used for the domain decomposition, we will not use blocking factor
         // to generate grids. Nonetheless, AMReX has asserts in place that validate that the
         // number of cells is a multiple of blocking factor. We set the blocking factor to 1 so those
         // AMReX asserts will always pass.
-        const amrex::ParmParse pp_warpx("warpx");
+        const auto pp_warpx = amrex::ParmParse{"warpx"};
         if (pp_warpx.contains("numprocs"))
         {
             amrex::ParmParse pp_amr("amr");
             pp_amr.add("blocking_factor", 1);
         }
+    }
 
-        //See https://github.com/AMReX-Codes/amrex/pull/3763
-#ifdef AMREX_USE_GPU
-        bool warpx_do_device_synchronize = true;
-#else
-        bool warpx_do_device_synchronize = false;
-#endif
-        pp_warpx.query("do_device_synchronize", warpx_do_device_synchronize);
-        bool do_device_synchronize = warpx_do_device_synchronize;
-        amrex::ParmParse pp_tiny_profiler("tiny_profiler");
-        if (pp_tiny_profiler.queryAdd("device_synchronize_around_region", do_device_synchronize) )
-        {
-            WARPX_ALWAYS_ASSERT_WITH_MESSAGE(
-                do_device_synchronize == warpx_do_device_synchronize,
-                "tiny_profiler.device_synchronize_around_region overrides warpx.do_device_synchronize.");
-        }
-
+    void override_default_tiling_option_for_particles ()
+    {
         // Here we override the default tiling option for particles, which is always
         // "false" in AMReX, to "false" if compiling for GPU execution and "true"
         // if compiling for CPU.
-        {
-            amrex::ParmParse pp_particles("particles");
-#ifdef AMREX_USE_GPU
-            bool do_tiling = false; // By default, tiling is off on GPU
-#else
-            bool do_tiling = true;
-#endif
-            pp_particles.queryAdd("do_tiling", do_tiling);
-        }
+        auto pp_particles = amrex::ParmParse{"particles"};
+        auto do_tiling = !amrex_use_gpu; // By default, tiling is off on GPU
+        pp_particles.queryAdd("do_tiling", do_tiling);
+    }
+
+    /** Overwrite defaults in AMReX Inputs
+     *
+     * This overwrites defaults in amrex::ParmParse for inputs.
+     */
+    void
+    overwrite_amrex_parser_defaults ()
+    {
+        override_default_abort_on_out_of_gpu_memory();
+        override_default_the_arena_is_managed();
+        override_default_omp_threads();
+        apply_workaround_for_warpx_numprocs();
+        set_device_synchronization();
+        override_default_tiling_option_for_particles();
     }
 }