Enable cfl only of explicit schemes

Signed-off-by: Santiago Ospina <santiago.ospina@iup.uni-heidelberg.de>

dune/dorie/interface/transport_simulation.cc

@@ -144,9 +144,12 @@ void TransportSimulation<Traits>::step ()
     auto t = controller->getTime();
     suggest_timestep(controller->getDT());
 
-    // for some reason dt!=this->dt
-    const auto _dt = this->dt;
+    double courant_number = 0.5; //FIXME: add keyword in inifile
+    if (not ts_param->implicit())
+      this->suggest_timestep(courant_number*Dune::Dorie::cfl_condition(*gf_water_flux));
 
+    // for some reason dt!=this->dt, any idea why?
+    
     // Check whether time intervals of grid functions are valid
     if (Dune::FloatCmp::gt(water_flux_interval.begin,t+this->dt))
       DUNE_THROW(Dune::Exception," ");

dune/dorie/interface/transport_simulation.hh

@@ -298,11 +298,7 @@ public:
 
   void suggest_timestep(TimeField _dt) override
   {
-    auto cfl_dt = 0.3*Dune::Dorie::cfl_condition(*gf_water_flux); // FIXME
-    std::cout << "cfl_dt: " << cfl_dt << std::endl;
-    this->dt = std::min(_dt,controller->getDT());
-    this->dt = std::min(dt,cfl_dt);
-    std::cout << "dt: " << cfl_dt << std::endl;
+    dt = std::min(_dt,controller->getDT());
   }
 
   // TODO: Define data exchange with richards

dune/dorie/solver/util_cfl_condition.hh

@@ -55,7 +55,7 @@ namespace Dorie{
       for (int i = 1; i < geo.corners(); ++i)
         for (int j = 0; j < i-1; ++j)
           h_T = std::max(h_T,(geo.corner(i)-geo.corner(j)).two_norm());
-      std::cout << "h_T: " << h_T << std::endl;
+
       // Check that h_T is not zero in debug mode, who knows.
       assert(Dune::FloatCmp::gt(h_T,0.));
 
@@ -69,15 +69,12 @@ namespace Dorie{
         gf.evaluate(cell,x,water_flux);
         max_water_flux = std::max(max_water_flux,water_flux.two_norm());
       }
-      std::cout << "max_water_flux: " << max_water_flux << std::endl;
+
       // Calculate the cfl for this cell 
       if (Dune::FloatCmp::gt(max_water_flux,0.))
         suggested_dt = std::min(suggested_dt,h_T/max_water_flux);
-
-      std::cout << "suggested_dt: " << suggested_dt << std::endl;
     }
 
-    std::cout << "FINAL suggested_dt: " << suggested_dt << std::endl;
     // Communicate the lowest cfl number to all procesors
     suggested_dt = gv.comm().min(suggested_dt);
     return suggested_dt;