Better definition of CFL condition. Now able to cope with changes of kernel.

src/const.h

@@ -38,7 +38,7 @@
   1.f /* Value taken from (Price,2008), not used in legacy gadget mode */
 
 /* Time integration constants. */
-#define const_cfl 0.2f
+#define const_cfl 0.1f
 #define const_ln_max_h_change                                           \
   0.231111721f /* Particle can't change volume by more than a factor of \
                   2=1.26^3 over one time step */

src/hydro/Gadget2/hydro.h

@@ -34,7 +34,7 @@ __attribute__((always_inline)) INLINE static float hydro_compute_timestep(
   const float dt_accel = sqrtf(2.f);  // MATTHIEU
 
   /* CFL condition */
-  const float dt_cfl = 2.f * const_cfl * p->h / p->v_sig;
+  const float dt_cfl = 2.f * const_cfl * kernel_gamma * p->h / p->v_sig;
 
   return fminf(dt_cfl, dt_accel);
 }