feat: [WIP] Add diffusion load balancing

demos/FiniteVolume/advection_2d.cpp

@@ -16,6 +16,9 @@
 #include <samurai/stencil_field.hpp>
 #include <samurai/subset/node.hpp>
 
+#include <samurai/load_balancing.hpp>
+#include <samurai/load_balancing_diffusion.hpp>
+
 #include <filesystem>
 namespace fs = std::filesystem;
 
@@ -149,18 +152,24 @@ void save(const fs::path& path, const std::string& filename, const Field& u, con
     auto mesh   = u.mesh();
     auto level_ = samurai::make_scalar_field<std::size_t>("level", mesh);
 
+    auto domain_ = samurai::make_scalar_field<int>("domain", mesh);
+
     if (!fs::exists(path))
     {
         fs::create_directory(path);
     }
 
+    int mrank = 0;
+
     samurai::for_each_cell(mesh,
                            [&](const auto& cell)
                            {
-                               level_[cell] = cell.level;
+                               level_[cell]  = cell.level;
+                               domain_[cell] = mrank;
                            });
 #ifdef SAMURAI_WITH_MPI
     mpi::communicator world;
+    mrank = world.rank();
     samurai::save(path, fmt::format("{}_size_{}{}", filename, world.size(), suffix), mesh, u, level_);
 #else
     samurai::save(path, fmt::format("{}{}", filename, suffix), mesh, u, level_);
@@ -194,9 +203,10 @@ int main(int argc, char* argv[])
     bool correction       = false;
 
     // Output parameters
-    fs::path path        = fs::current_path();
-    std::string filename = "FV_advection_2d";
-    std::size_t nfiles   = 1;
+    fs::path path              = fs::current_path();
+    std::string filename       = "FV_advection_2d";
+    std::size_t nfiles         = 1;
+    std::size_t nt_loadbalance = 10; // nombre d'iteration entre les equilibrages
 
     app.add_option("--min-corner", min_corner, "The min corner of the box")->capture_default_str()->group("Simulation parameters");
     app.add_option("--max-corner", max_corner, "The max corner of the box")->capture_default_str()->group("Simulation parameters");
@@ -207,6 +217,9 @@ int main(int argc, char* argv[])
     app.add_option("--restart-file", restart_file, "Restart file")->capture_default_str()->group("Simulation parameters");
     app.add_option("--min-level", min_level, "Minimum level of the multiresolution")->capture_default_str()->group("Multiresolution");
     app.add_option("--max-level", max_level, "Maximum level of the multiresolution")->capture_default_str()->group("Multiresolution");
+#ifdef SAMURAI_WITH_MPI
+    app.add_option("--nt-loadbalance", nt_loadbalance, "Maximum level of the multiresolution")->capture_default_str()->group("Multiresolution");
+#endif
     app.add_option("--mr-eps", mr_epsilon, "The epsilon used by the multiresolution to adapt the mesh")
         ->capture_default_str()
         ->group("Multiresolution");
@@ -251,8 +264,19 @@ int main(int argc, char* argv[])
     std::size_t nsave = 1;
     std::size_t nt    = 0;
 
+#ifdef SAMURAI_WITH_MPI
+    Load_balancing::Diffusion balancer;
+#endif
+
     while (t != Tf)
     {
+#ifdef SAMURAI_WITH_MPI
+        if (((nt % nt_loadbalance == 0) && nt > 1) || nt == 1)
+        {
+            balancer.load_balance(mesh, u);
+        }
+#endif
+
         MRadaptation(mr_epsilon, mr_regularity);
 
         t += dt;

demos/FiniteVolume/burgers.cpp

@@ -8,6 +8,9 @@
 #include <samurai/samurai.hpp>
 #include <samurai/schemes/fv.hpp>
 
+#include <samurai/load_balancing.hpp>
+#include <samurai/load_balancing_diffusion.hpp>
+
 #include <filesystem>
 namespace fs = std::filesystem;
 
@@ -85,6 +88,10 @@ int main_dim(int argc, char* argv[])
     std::string filename = "burgers_" + std::to_string(dim) + "D";
     std::size_t nfiles   = 50;
 
+#if SAMURAI_WITH_MPI
+    std::size_t nt_loadbalance = 10; // nombre d'iteration entre les equilibrages
+#endif
+
     app.add_option("--left", left_box, "The left border of the box")->capture_default_str()->group("Simulation parameters");
     app.add_option("--right", right_box, "The right border of the box")->capture_default_str()->group("Simulation parameters");
     app.add_option("--init-sol", init_sol, "Initial solution: hat/linear/bands")->capture_default_str()->group("Simulation parameters");
@@ -120,6 +127,10 @@ int main_dim(int argc, char* argv[])
     Box box(box_corner1, box_corner2);
     samurai::MRMesh<Config> mesh;
 
+#ifdef SAMURAI_WITH_MPI
+    Load_balancing::Diffusion balancer;
+#endif
+
     auto u    = samurai::make_vector_field<n_comp>("u", mesh);
     auto u1   = samurai::make_vector_field<n_comp>("u1", mesh);
     auto u2   = samurai::make_vector_field<n_comp>("u2", mesh);
@@ -247,6 +258,13 @@ int main_dim(int argc, char* argv[])
 
     while (t != Tf)
     {
+#ifdef SAMURAI_WITH_MPI
+        if ((nt % nt_loadbalance == 0) && nt > 1)
+        {
+            balancer.load_balance(mesh, u);
+        }
+#endif
+
         // Move to next timestep
         t += dt;
         if (t > Tf)

demos/FiniteVolume/linear_convection.cpp

@@ -8,6 +8,9 @@
 #include <samurai/samurai.hpp>
 #include <samurai/schemes/fv.hpp>
 
+#include <samurai/load_balancing.hpp>
+#include <samurai/load_balancing_diffusion.hpp>
+
 #include <filesystem>
 namespace fs = std::filesystem;
 
@@ -46,7 +49,6 @@ int main(int argc, char* argv[])
     //--------------------//
     // Program parameters //
     //--------------------//
-
     // Simulation parameters
     double left_box  = -1;
     double right_box = 1;
@@ -68,7 +70,9 @@ int main(int argc, char* argv[])
     fs::path path        = fs::current_path();
     std::string filename = "linear_convection_" + std::to_string(dim) + "D";
     std::size_t nfiles   = 0;
-
+#ifdef SAMURAI_WITH_MPI
+    std::size_t nt_loadbalance = 10;
+#endif
     app.add_option("--left", left_box, "The left border of the box")->capture_default_str()->group("Simulation parameters");
     app.add_option("--right", right_box, "The right border of the box")->capture_default_str()->group("Simulation parameters");
     app.add_option("--Ti", t, "Initial time")->capture_default_str()->group("Simulation parameters");
@@ -78,6 +82,9 @@ int main(int argc, char* argv[])
     app.add_option("--cfl", cfl, "The CFL")->capture_default_str()->group("Simulation parameters");
     app.add_option("--min-level", min_level, "Minimum level of the multiresolution")->capture_default_str()->group("Multiresolution");
     app.add_option("--max-level", max_level, "Maximum level of the multiresolution")->capture_default_str()->group("Multiresolution");
+#ifdef SAMURAI_WITH_MPI
+    app.add_option("--nt-loadbalance", nt_loadbalance, "Maximum level of the multiresolution")->capture_default_str()->group("Multiresolution");
+#endif
     app.add_option("--mr-eps", mr_epsilon, "The epsilon used by the multiresolution to adapt the mesh")
         ->capture_default_str()
         ->group("Multiresolution");
@@ -150,6 +157,10 @@ int main(int argc, char* argv[])
     }
     auto conv = samurai::make_convection_weno5<decltype(u)>(velocity);
 
+#ifdef SAMURAI_WITH_MPI
+    Load_balancing::Diffusion balancer;
+#endif
+
     //--------------------//
     //   Time iteration   //
     //--------------------//
@@ -174,6 +185,12 @@ int main(int argc, char* argv[])
     }
     while (t != Tf)
     {
+#ifdef SAMURAI_WITH_MPI
+        if (nt % nt_loadbalance == 0 && nt > 1)
+        {
+            balancer.load_balance(mesh, u);
+        }
+#endif
         // Move to next timestep
         t += dt;
         if (t > Tf)
@@ -182,7 +199,6 @@ int main(int argc, char* argv[])
             t = Tf;
         }
         std::cout << fmt::format("iteration {}: t = {:.2f}, dt = {}", nt++, t, dt) << std::flush;
-
         // Mesh adaptation
         MRadaptation(mr_epsilon, mr_regularity);
         samurai::update_ghost_mr(u);