Clean-up before merge

src/const.h

@@ -40,8 +40,8 @@
 #define const_isothermal_internal_energy 20.2615290634f
 
 /* Dimensionality of the problem */
-//#define HYDRO_DIMENSION_3D
-#define HYDRO_DIMENSION_2D
+#define HYDRO_DIMENSION_3D
+//#define HYDRO_DIMENSION_2D
 //#define HYDRO_DIMENSION_1D
 
 /* Hydrodynamical adiabatic index. */
@@ -64,8 +64,8 @@
 
 /* SPH variant to use */
 //#define MINIMAL_SPH
-//#define GADGET2_SPH
-#define HOPKINS_PE_SPH
+#define GADGET2_SPH
+//#define HOPKINS_PE_SPH
 //#define DEFAULT_SPH
 //#define GIZMO_SPH
 

src/hydro/PressureEntropy/hydro.h

@@ -305,20 +305,21 @@ __attribute__((always_inline)) INLINE static void hydro_prepare_force(
 
   /* Compute the pressure */
   const float half_dt = (ti_current - (p->ti_begin + p->ti_end) / 2) * timeBase;
-  const float pressure = hydro_get_pressure(p, half_dt);
+  const float entropy = hydro_get_entropy(p, half_dt);
+  const float pressure = gas_pressure_from_entropy(p->rho_bar, entropy);
 
   /* Compute the sound speed from the pressure*/
   const float soundspeed = gas_soundspeed_from_pressure(p->rho_bar, pressure);
 
-  /* Divide the pressure by the density squared to get the SPH term */
-  const float rho_bar_inv = 1.f / p->rho_bar;
-  const float P_over_rho2 = pressure * rho_bar_inv * rho_bar_inv;
-
   /* Compute the Balsara switch */
   const float balsara =
       abs_div_v / (abs_div_v + curl_v + 0.0001f * soundspeed / fac_mu / p->h);
 
-  /* Compute "grad h" term */
+  /* Divide the pressure by the density squared to get the SPH term */
+  const float rho_bar_inv = 1.f / p->rho_bar;
+  const float P_over_rho2 = pressure * rho_bar_inv * rho_bar_inv;
+
+  /* Compute "grad h" term (note we use rho here and not rho_bar !)*/
   const float rho_inv = 1.f / p->rho;
   const float entropy_minus_one_over_gamma = 1.f / p->entropy_one_over_gamma;
   const float rho_dh =