From cd174d505acbd8b17a03dceb3070548e95a26dc2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Del=20Pino?= <stephane.delpino44@gmail.com>
Date: Mon, 26 Mar 2018 15:17:04 +0200
Subject: [PATCH] Added a "cleaner" class version of the Accoustic solver

---
 experimental/AcousticSolver.cpp          | 253 +++++++++++++++++++++++
 experimental/AcousticSolver.hpp          |  31 +++
 experimental/CMakeLists.txt              |   1 +
 experimental/RawKokkosAcousticSolver.cpp |  13 --
 main.cpp                                 |  38 +++-
 5 files changed, 318 insertions(+), 18 deletions(-)
 create mode 100644 experimental/AcousticSolver.cpp
 create mode 100644 experimental/AcousticSolver.hpp

diff --git a/experimental/AcousticSolver.cpp b/experimental/AcousticSolver.cpp
new file mode 100644
index 000000000..3f9984d2b
--- /dev/null
+++ b/experimental/AcousticSolver.cpp
@@ -0,0 +1,253 @@
+#include <AcousticSolver.hpp>
+#include <rang.hpp>
+
+
+KOKKOS_INLINE_FUNCTION
+double AcousticSolver::e(double rho, double p, double gamma) const
+{
+  return p/(rho*(gamma-1));
+}
+
+KOKKOS_INLINE_FUNCTION
+double AcousticSolver::p(double rho, double e, double gamma) const
+{
+  return (gamma-1)*rho*e;
+}
+
+typedef const double my_double;
+
+struct AcousticSolver::ReduceMin {
+private:
+  const Kokkos::View<my_double*> x_;
+
+public:
+  typedef Kokkos::View<my_double*>::non_const_value_type value_type;
+
+  ReduceMin(const Kokkos::View<my_double*>& x) : x_ (x) {}
+
+  typedef Kokkos::View<my_double*>::size_type size_type;
+    
+  KOKKOS_INLINE_FUNCTION void
+  operator() (const size_type i, value_type& update) const
+  {
+    if (x_(i) < update) {
+      update = x_(i);
+    }
+  }
+
+  KOKKOS_INLINE_FUNCTION void
+  join (volatile value_type& dst,
+	const volatile value_type& src) const
+  {
+    if (src < dst) {
+      dst = src;
+    }
+  }
+
+  KOKKOS_INLINE_FUNCTION void
+  init (value_type& dst) const
+  { // The identity under max is -Inf.
+    dst= Kokkos::reduction_identity<value_type>::min();
+  }
+};
+    
+
+KOKKOS_INLINE_FUNCTION
+double AcousticSolver::
+acoustic_dt(const Kokkos::View<const double*>& Vj,
+	    const Kokkos::View<const double*>& cj) const
+{
+  const size_t nj = Vj.size();
+  double dt = std::numeric_limits<double>::max();
+
+  Kokkos::View<double*> Vj_cj("Vj_cj", nj);
+
+  Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+      Vj_cj[j] = Vj[j]/cj[j];
+    });
+
+  Kokkos::parallel_reduce(nj, ReduceMin(Vj_cj), dt);
+
+  return dt;
+}
+
+
+KOKKOS_INLINE_FUNCTION
+void AcousticSolver::computeExplicitFluxes(const Kokkos::View<const double*>& xr,
+					   const Kokkos::View<const double*>& xj,
+					   const Kokkos::View<const double*>& rhoj,
+					   const Kokkos::View<const double*>& uj,
+					   const Kokkos::View<const double*>& pj,
+					   const Kokkos::View<const double*>& cj,
+					   const Kokkos::View<const double*>& Vj,
+					   Kokkos::View<double*>& ur,
+					   Kokkos::View<double*>& pr) const
+{
+  // calcul de ur
+  ur[0]=0;
+  const size_t nr = ur.size();
+  const size_t nj = uj.size();
+
+  Kokkos::parallel_for(nj-1, KOKKOS_LAMBDA(const int& j) {
+    const int r = j+1;
+    const int k = r;
+
+    const double ujr = uj[j];
+    const double ukr = uj[k];
+    const double pjr = pj[j];
+    const double pkr = pj[k];
+
+    ur[r]=(rhoj[j]*cj[j]*ujr + rhoj[k]*cj[k]*ukr + pjr-pkr)/(rhoj[j]*cj[j]+rhoj[k]*cj[k]);
+    });
+  ur[nr-1]=0;
+
+  // calcul de pr
+  pr[0] = pj[0] + rhoj[0]*cj[0]*(ur[0] - uj[0]);
+  Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j) {
+    const int r = j+1;
+
+    const double ujr = uj[j];
+    const double pjr = pj[j];
+
+    pr[r]=pjr+rhoj[j]*cj[j]*(ujr-ur[r]);
+    });
+}
+
+
+AcousticSolver::AcousticSolver(const long int& nj)
+{
+  Kokkos::View<double*> xj("xj", nj);
+  Kokkos::View<double*> rhoj("rhoj", nj);
+
+  Kokkos::View<double*> uj("uj", nj);
+
+  Kokkos::View<double*> Ej("Ej", nj);
+  Kokkos::View<double*> ej("ej", nj);
+  Kokkos::View<double*> pj("pj", nj);
+  Kokkos::View<double*> Vj("Vj", nj);
+  Kokkos::View<double*> gammaj("gammaj", nj);
+  Kokkos::View<double*> cj("cj", nj);
+  Kokkos::View<double*> mj("mj", nj);
+  Kokkos::View<double*> inv_mj("inv_mj", nj);
+
+  const int nr=nj+1;
+
+  Kokkos::View<double*>  xr("xr", nr);
+
+  const double delta_x = 1./nj;
+
+  Kokkos::parallel_for(nr, KOKKOS_LAMBDA(const int& r){
+      xr[r] = r*delta_x;
+    });
+
+
+  Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+      xj[j] = 0.5*(xr[j]+xr[j+1]);
+    });
+
+  Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+      Vj[j] = xr[j+1]-xr[j];
+    });
+
+  Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+    if (xj[j]<0.5) {
+      rhoj[j]=1;
+    } else {
+      rhoj[j]=0.125;
+    }
+  });
+
+  Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+    if (xj[j]<0.5) {
+      pj[j]=1;
+    } else {
+      pj[j]=0.1;
+    }
+  });
+
+  Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+      gammaj[j] = 1.4;
+    });
+
+  Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+    ej[j] = e(rhoj[j],pj[j],gammaj[j]);
+  });
+
+  Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+    Ej[j] = ej[j]+0.5*uj[j]*uj[j];
+  });
+
+  Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+    cj[j] = std::sqrt(gammaj[j]*pj[j]/rhoj[j]);
+  });
+
+  Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+    mj[j] = rhoj[j] * Vj[j];
+  });
+
+  const double tmax=0.2;
+  double t=0;
+
+  int itermax=std::numeric_limits<int>::max();
+  int iteration=0;
+
+  while((t<tmax) and (iteration<itermax)) {
+    double dt = 0.4*acoustic_dt(Vj, cj);
+    if (t+dt<tmax) {
+      t+=dt;
+    } else {
+      dt=tmax-t;
+      t=tmax;
+    }
+
+    // if (iteration%100 == 0) {
+    //   std::cout << "dt=" << dt << " t=" << t << " i=" << iteration << std::endl;
+    // }
+    
+    Kokkos::View<double*> ur("ur", nr);
+    Kokkos::View<double*> pr("pr", nr);
+
+    computeExplicitFluxes(xr, xj,
+			  rhoj, uj, pj, cj, Vj,
+			  ur, pr);
+
+    Kokkos::View<double*> new_uj("new_uj", nj);
+    Kokkos::View<double*> new_Ej("new_Ej", nj);
+    
+    Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+      int rm=j;
+      int rp=j+1;
+
+      new_uj[j] = uj[j] + dt/mj[j]*(pr[rm]-pr[rp]);
+      new_Ej[j] = Ej[j] + dt/mj[j]*(pr[rm]*ur[rm]-pr[rp]*ur[rp]);
+      });
+
+    uj=new_uj;
+    Ej=new_Ej;
+
+    Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+	ej[j] = Ej[j] - 0.5 * uj[j]*uj[j];
+      });
+
+    Kokkos::parallel_for(nr, KOKKOS_LAMBDA(const int& r){
+      xr[r] += dt*ur[r];
+      });
+
+    Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+      xj[j] = 0.5*(xr[j]+xr[j+1]);
+      Vj[j] = xr[j+1]-xr[j];
+      });
+
+    Kokkos::parallel_for(nj, KOKKOS_LAMBDA(const int& j){
+	rhoj[j] = mj[j]/Vj[j];
+	pj[j] = p(rhoj[j], ej[j], gammaj[j]);
+	cj[j] = std::sqrt(gammaj[j]*pj[j]/rhoj[j]); // inv_mj*vj
+      });
+    
+    ++iteration;
+  }
+
+  std::cout << "* " << rang::style::underline << "Final time" << rang::style::reset
+	    << ":  " << rang::fgB::green << t << rang::fg::reset << " (" << iteration << " iterations)\n";
+
+}
diff --git a/experimental/AcousticSolver.hpp b/experimental/AcousticSolver.hpp
new file mode 100644
index 000000000..153d64f56
--- /dev/null
+++ b/experimental/AcousticSolver.hpp
@@ -0,0 +1,31 @@
+#ifndef ACOUSTIC_SOLVER_HPP
+#define ACOUSTIC_SOLVER_HPP
+
+#include <Kokkos_Core.hpp>
+
+class AcousticSolver 
+{
+private:
+
+  inline double e(double rho, double p, double gamma) const;
+  inline double p(double rho, double e, double gamma) const;
+
+  inline double acoustic_dt(const Kokkos::View<const double*>& Vj,
+			    const Kokkos::View<const double*>& cj) const;
+
+  inline void computeExplicitFluxes(const Kokkos::View<const double*>& xr,
+				    const Kokkos::View<const double*>& xj,
+				    const Kokkos::View<const double*>& rhoj,
+				    const Kokkos::View<const double*>& uj,
+				    const Kokkos::View<const double*>& pj,
+				    const Kokkos::View<const double*>& cj,
+				    const Kokkos::View<const double*>& Vj,
+				    Kokkos::View<double*>& ur,
+				    Kokkos::View<double*>& pr) const;
+
+  struct ReduceMin;
+public:
+  AcousticSolver(const long int& nj);
+};
+
+#endif // ACOUSTIC_SOLVER_HPP
diff --git a/experimental/CMakeLists.txt b/experimental/CMakeLists.txt
index 30584083c..1625c89b3 100644
--- a/experimental/CMakeLists.txt
+++ b/experimental/CMakeLists.txt
@@ -9,6 +9,7 @@ include_directories(${PASTIS_SOURCE_DIR}/packages/rang/include)
 add_library(
   PastisExperimental
   RawKokkosAcousticSolver.cpp
+  AcousticSolver.cpp
   )
 
 
diff --git a/experimental/RawKokkosAcousticSolver.cpp b/experimental/RawKokkosAcousticSolver.cpp
index 77b68454c..b7369fde4 100644
--- a/experimental/RawKokkosAcousticSolver.cpp
+++ b/experimental/RawKokkosAcousticSolver.cpp
@@ -199,10 +199,6 @@ void AcousticSolver(const long int& nj)
       dt=tmax-t;
       t=tmax;
     }
-
-    if (iteration%100 == 0) {
-      std::cout << "dt=" << dt << " t=" << t << " i=" << iteration << std::endl;
-    }
     
     Kokkos::View<double*> ur("ur", nr);
     Kokkos::View<double*> pr("pr", nr);
@@ -243,15 +239,6 @@ void AcousticSolver(const long int& nj)
 
   std::cout << "* " << rang::style::underline << "Final time" << rang::style::reset
 	    << ":  " << rang::fgB::green << t << rang::fg::reset << " (" << iteration << " iterations)\n";
-
-  // {
-  //   std::ofstream fout("rho");
-  
-  //   for (int j=0; j<nj; ++j) {
-  //     fout << xj[j] << ' ' << rhoj[j] << '\n';
-  //   }
-  // }
-
 }
 
 }
diff --git a/main.cpp b/main.cpp
index ee597d14f..f1b143f45 100644
--- a/main.cpp
+++ b/main.cpp
@@ -7,10 +7,12 @@
 #include <ConsoleManager.hpp>
 
 #include <RawKokkosAcousticSolver.hpp>
+#include <AcousticSolver.hpp>
 
 #include <CLI/CLI.hpp>
 #include <cassert>
 #include <limits>
+#include <map>
 
 int main(int argc, char *argv[])
 {
@@ -73,13 +75,39 @@ int main(int argc, char *argv[])
   Kokkos::initialize(argc, argv);
   Kokkos::DefaultExecutionSpace::print_configuration(std::cout);
 
-  Kokkos::Timer timer;
-  timer.reset();
-  RawKokkos::AcousticSolver(number);
-  double count_time = timer.seconds();
-  std::cout << "* Execution time: " << rang::style::bold << count_time << rang::style::reset << '\n';
+  std::map<std::string, double> method_cost_map;
+  // {
+  //   Kokkos::Timer timer;
+  //   timer.reset();
+  //   RawKokkos::AcousticSolver(number);
+  //   method_cost_map["RawKokkos"] = timer.seconds();
+  // }
+
+  {
+    Kokkos::Timer timer;
+    timer.reset();
+    AcousticSolver acoustic_solver(number);
+    method_cost_map["Class"] = timer.seconds();
+  }
 
   Kokkos::finalize();
 
+  std::cout << "----------------------\n";
+
+  std::string::size_type size=0;
+  for (const auto& method_cost : method_cost_map) {
+    size = std::max(size, method_cost.first.size());
+  }
+  size+=2;
+
+  for (const auto& method_cost : method_cost_map) {
+    std::cout << "* [" << std::setw(size) << std::left
+	      << method_cost.first
+	      << " ] Execution time: "
+	      << rang::style::bold
+	      << method_cost.second
+	      << rang::style::reset << '\n';
+  }
+
   return 0;
 }
-- 
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