Drift entopy in grad-h term for PE-SPH

src/hydro/PressureEntropy/hydro.h

@@ -338,11 +338,10 @@ __attribute__((always_inline)) INLINE static void hydro_prepare_force(
 
   /* 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 =
       1.f / (1.f + hydro_dimension_inv * p->h * p->density.rho_dh * rho_inv);
-  const float pressure_dh = p->density.pressure_dh * rho_inv * p->h *
-                            hydro_dimension_inv * entropy_minus_one_over_gamma;
+  const float pressure_dh =
+      p->density.pressure_dh * rho_inv * p->h * hydro_dimension_inv;
 
   const float grad_h_term = rho_dh * pressure_dh;
 

src/hydro/PressureEntropy/hydro_iact.h

@@ -255,8 +255,9 @@ __attribute__((always_inline)) INLINE static void runner_iact_force(
 
   /* Now, convolve with the kernel */
   const float visc_term = 0.5f * visc * (wi_dr + wj_dr);
-  const float sph_term = (S_gamma_j / S_gamma_i - f_i) * P_over_rho2_i * wi_dr +
-                         (S_gamma_i / S_gamma_j - f_j) * P_over_rho2_j * wj_dr;
+  const float sph_term =
+      (S_gamma_j / S_gamma_i - f_i / S_gamma_i) * P_over_rho2_i * wi_dr +
+      (S_gamma_i / S_gamma_j - f_j / S_gamma_j) * P_over_rho2_j * wj_dr;
 
   /* Eventually got the acceleration */
   const float acc = (visc_term + sph_term) * r_inv;
@@ -365,8 +366,9 @@ __attribute__((always_inline)) INLINE static void runner_iact_nonsym_force(
 
   /* Now, convolve with the kernel */
   const float visc_term = 0.5f * visc * (wi_dr + wj_dr);
-  const float sph_term = (S_gamma_j / S_gamma_i - f_i) * P_over_rho2_i * wi_dr +
-                         (S_gamma_i / S_gamma_j - f_j) * P_over_rho2_j * wj_dr;
+  const float sph_term =
+      (S_gamma_j / S_gamma_i - f_i / S_gamma_i) * P_over_rho2_i * wi_dr +
+      (S_gamma_i / S_gamma_j - f_j / S_gamma_j) * P_over_rho2_j * wj_dr;
 
   /* Eventually got the acceleration */
   const float acc = (visc_term + sph_term) * r_inv;