Better notation for some Gadget2-SPH variables.

src/hydro/Gadget2/hydro.h

@@ -231,18 +231,18 @@ __attribute__((always_inline)) INLINE static void hydro_end_density(
   p->density.wcount *= kernel_norm;
   p->density.wcount_dh *= h_inv * kernel_gamma * kernel_norm;
 
-  const float irho = 1.f / p->rho;
+  const float rho_inv = 1.f / p->rho;
 
   /* Compute the derivative term */
-  p->rho_dh = 1.f / (1.f + hydro_dimension_inv * p->h * p->rho_dh * irho);
+  p->rho_dh = 1.f / (1.f + hydro_dimension_inv * p->h * p->rho_dh * rho_inv);
 
   /* Finish calculation of the velocity curl components */
-  p->density.rot_v[0] *= h_inv_dim_plus_one * irho;
-  p->density.rot_v[1] *= h_inv_dim_plus_one * irho;
-  p->density.rot_v[2] *= h_inv_dim_plus_one * irho;
+  p->density.rot_v[0] *= h_inv_dim_plus_one * rho_inv;
+  p->density.rot_v[1] *= h_inv_dim_plus_one * rho_inv;
+  p->density.rot_v[2] *= h_inv_dim_plus_one * rho_inv;
 
   /* Finish calculation of the velocity divergence */
-  p->density.div_v *= h_inv_dim_plus_one * irho;
+  p->density.div_v *= h_inv_dim_plus_one * rho_inv;
 }
 
 /**
@@ -273,13 +273,13 @@ __attribute__((always_inline)) INLINE static void hydro_prepare_force(
   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 irho = 1.f / p->rho;
+  const float rho_inv = 1.f / p->rho;
 
   /* Divide the pressure by the density and density gradient */
-  const float P_over_rho2 = pressure * irho * irho * p->rho_dh;
+  const float P_over_rho2 = pressure * rho_inv * rho_inv * p->rho_dh;
 
   /* Compute the sound speed */
-  const float soundspeed = sqrtf(hydro_gamma * pressure * irho);
+  const float soundspeed = sqrtf(hydro_gamma * pressure * rho_inv);
 
   /* Compute the Balsara switch */
   const float balsara =
@@ -349,13 +349,13 @@ __attribute__((always_inline)) INLINE static void hydro_predict_extra(
   const float dt_entr = (t1 - (p->ti_begin + p->ti_end) / 2) * timeBase;
   const float pressure = hydro_get_pressure(p, dt_entr);
 
-  const float irho = 1.f / p->rho;
+  const float rho_inv = 1.f / p->rho;
 
   /* Divide the pressure by the density and density gradient */
-  const float P_over_rho2 = pressure * irho * irho * p->rho_dh;
+  const float P_over_rho2 = pressure * rho_inv * rho_inv * p->rho_dh;
 
   /* Compute the new sound speed */
-  const float soundspeed = sqrtf(hydro_gamma * pressure * irho);
+  const float soundspeed = sqrtf(hydro_gamma * pressure * rho_inv);
 
   /* Update variables */
   p->force.P_over_rho2 = P_over_rho2;

src/hydro/Gadget2/hydro_iact.h

@@ -248,17 +248,17 @@ __attribute__((always_inline)) INLINE static void runner_iact_nonsym_density(
   const float ri = 1.0f / r;
 
   /* Compute the kernel function */
-  const float h_inv = 1.0f / hi;
-  const float u = r * h_inv;
-  kernel_deval(u, &wi, &wi_dx);
+  const float hi_inv = 1.0f / hi;
+  const float ui = r * hi_inv;
+  kernel_deval(ui, &wi, &wi_dx);
 
   /* Compute contribution to the density */
   pi->rho += mj * wi;
-  pi->rho_dh -= mj * (hydro_dimension * wi + u * wi_dx);
+  pi->rho_dh -= mj * (hydro_dimension * wi + ui * wi_dx);
 
   /* Compute contribution to the number of neighbours */
   pi->density.wcount += wi;
-  pi->density.wcount_dh -= u * wi_dx;
+  pi->density.wcount_dh -= ui * wi_dx;
 
   const float fac = mj * wi_dx * ri;