some modification

HySoP/hysop/operator/stretching_d.py

@@ -62,7 +62,6 @@ class Stretching_d(DiscreteOperator):
          -integrate with the chosen method (RK4. RK2. euler)
         """
         self.compute_time = time.time()
-        
 
         if self.method is not None:
 
@@ -97,8 +96,8 @@ class Stretching_d(DiscreteOperator):
             # Time integration 
             for i in range (self.ndt) :
                 methodInt=self.method(self.fonction)
-                self.res_vorticity = methodInt.integrate(self.fonction.apply, t, self.dtstretch, self.vorticity.data)
-            self.vorticity.data= np.copy(self.res_vorticity)
+                self.vorticity.data = methodInt.integrate(self.fonction.apply, t, self.dtstretch, self.vorticity.data)
+
 
             # Ghosts synchronization
 #            self.OpSynchronize.apply([self.vorticity.data, self.velocity.data])

HySoP/hysop/particular_solvers/basic.py

@@ -29,7 +29,7 @@ class ParticleSolver(Solver):
     Link with differents numericals methods used.
     """
     def __init__(self, problem, t_end, dt,
-                 ODESolver=None,
+                 ODESolver=RK3,
                  InterpolationMethod=None,
                  RemeshingMethod=None,
                  splittingMethod='strang',