Port changes to other hydro schemes. Adevertize what we do at start-up

src/hydro/Default/hydro.h

@@ -18,6 +18,7 @@
  ******************************************************************************/
 
 #include "approx_math.h"
+#include "gamma.h"
 
 /**
  * @brief Computes the hydro time-step of a given particle
@@ -138,12 +139,11 @@ __attribute__((always_inline)) INLINE static void hydro_prepare_force(
 
   /* Compute this particle's sound speed. */
   const float u = p->u;
-  const float fc = p->force.c =
-      sqrtf(const_hydro_gamma * (const_hydro_gamma - 1.0f) * u);
+  const float fc = p->force.c = sqrtf(hydro_gamma * hydro_gamma_minus_one * u);
 
   /* Compute the P/Omega/rho2. */
   xp->omega = 1.0f + 0.3333333333f * h * p->rho_dh / p->rho;
-  p->force.POrho2 = u * (const_hydro_gamma - 1.0f) / (p->rho * xp->omega);
+  p->force.POrho2 = u * hydro_gamma_minus_one / (p->rho * xp->omega);
 
   /* Balsara switch */
   p->force.balsara = normDiv_v / (normDiv_v + normCurl_v + 0.0001f * fc * ih);
@@ -207,7 +207,7 @@ __attribute__((always_inline)) INLINE static void hydro_predict_extra(
     u = p->u *= expf(w);
 
   /* Predict gradient term */
-  p->force.POrho2 = u * (const_hydro_gamma - 1.0f) / (p->rho * xp->omega);
+  p->force.POrho2 = u * hydro_gamma_minus_one / (p->rho * xp->omega);
 }
 
 /**

src/hydro/Default/hydro_iact.h

@@ -20,6 +20,8 @@
 #ifndef SWIFT_RUNNER_IACT_H
 #define SWIFT_RUNNER_IACT_H
 
+#include "gamma.h"
+
 /**
  * @brief SPH interaction functions following the Gadget-2 version of SPH.
  *
@@ -408,7 +410,7 @@ __attribute__((always_inline)) INLINE static void runner_iact_force(
   Pi_ij *= (pi->force.balsara + pj->force.balsara);
 
   /* Thermal conductivity */
-  v_sig_u = sqrtf(2.f * (const_hydro_gamma - 1.f) *
+  v_sig_u = sqrtf(2.f * hydro_gamma_minus_one *
                   fabs(rhoi * pi->u - rhoj * pj->u) / (rhoi + rhoj));
   tc = const_conductivity_alpha * v_sig_u / (rhoi + rhoj);
   tc *= (wi_dr + wj_dr);
@@ -608,7 +610,7 @@ __attribute__((always_inline)) INLINE static void runner_iact_vec_force(
   Pi_ij.v *= (wi_dr.v + wj_dr.v);
 
   /* Thermal conductivity */
-  v_sig_u.v = vec_sqrt(vec_set1(2.f * (const_hydro_gamma - 1.f)) *
+  v_sig_u.v = vec_sqrt(vec_set1(2.f * hydro_gamma_minus_one) *
                        vec_fabs(pirho.v * piu.v - pjrho.v * pju.v) /
                        (pirho.v + pjrho.v));
   tc.v = vec_set1(const_conductivity_alpha) * v_sig_u.v / (pirho.v + pjrho.v);
@@ -721,7 +723,7 @@ __attribute__((always_inline)) INLINE static void runner_iact_nonsym_force(
   Pi_ij *= (pi->force.balsara + pj->force.balsara);
 
   /* Thermal conductivity */
-  v_sig_u = sqrtf(2.f * (const_hydro_gamma - 1.f) *
+  v_sig_u = sqrtf(2.f * hydro_gamma_minus_one *
                   fabs(rhoi * pi->u - rhoj * pj->u) / (rhoi + rhoj));
   tc = const_conductivity_alpha * v_sig_u / (rhoi + rhoj);
   tc *= (wi_dr + wj_dr);

src/hydro/Minimal/hydro.h

@@ -18,6 +18,7 @@
  ******************************************************************************/
 
 #include "approx_math.h"
+#include "gamma.h"
 
 /**
  * @brief Computes the hydro time-step of a given particle
@@ -132,7 +133,7 @@ __attribute__((always_inline)) INLINE static void hydro_end_density(
 __attribute__((always_inline)) INLINE static void hydro_prepare_force(
     struct part* p, struct xpart* xp, int ti_current, double timeBase) {
 
-  p->force.pressure = p->rho * p->u * (const_hydro_gamma - 1.f);
+  p->force.pressure = p->rho * p->u * hydro_gamma_minus_one;
 }
 
 /**
@@ -175,7 +176,7 @@ __attribute__((always_inline)) INLINE static void hydro_predict_extra(
   p->u = xp->u_full;
 
   /* Need to recompute the pressure as well */
-  p->force.pressure = p->rho * p->u * (const_hydro_gamma - 1.f);
+  p->force.pressure = p->rho * p->u * hydro_gamma_minus_one;
 }
 
 /**

src/hydro/Minimal/hydro_iact.h

@@ -19,6 +19,8 @@
 #ifndef SWIFT_RUNNER_IACT_MINIMAL_H
 #define SWIFT_RUNNER_IACT_MINIMAL_H
 
+#include "gamma.h"
+
 /**
  * @brief Minimal conservative implementation of SPH
  *
@@ -128,8 +130,8 @@ __attribute__((always_inline)) INLINE static void runner_iact_force(
                      (pi->v[2] - pj->v[2]) * dx[2];
 
   /* Compute sound speeds */
-  const float ci = sqrtf(const_hydro_gamma * pressurei / rhoi);
-  const float cj = sqrtf(const_hydro_gamma * pressurej / rhoj);
+  const float ci = sqrtf(hydro_gamma * pressurei / rhoi);
+  const float cj = sqrtf(hydro_gamma * pressurej / rhoj);
   const float v_sig = ci + cj;
 
   /* SPH acceleration term */
@@ -200,8 +202,8 @@ __attribute__((always_inline)) INLINE static void runner_iact_nonsym_force(
                      (pi->v[2] - pj->v[2]) * dx[2];
 
   /* Compute sound speeds */
-  const float ci = sqrtf(const_hydro_gamma * pressurei / rhoi);
-  const float cj = sqrtf(const_hydro_gamma * pressurej / rhoj);
+  const float ci = sqrtf(hydro_gamma * pressurei / rhoi);
+  const float cj = sqrtf(hydro_gamma * pressurej / rhoj);
   const float v_sig = ci + cj;
 
   /* SPH acceleration term */

src/hydro/Minimal/hydro_io.h

@@ -104,7 +104,6 @@ void writeSPHflavour(hid_t h_grpsph) {
 
   /* Kernel function description */
   writeAttribute_s(h_grpsph, "Kernel", kernel_name);
-  writeAttribute_f(h_grpsph, "Hydro gamma", const_hydro_gamma);
 
   /* Viscosity and thermal conduction */
   /* Nothing in this minimal model... */

src/hydro_properties.c

@@ -26,6 +26,7 @@
 
 /* Local headers. */
 #include "error.h"
+#include "gamma.h"
 #include "hydro.h"
 #include "kernel_hydro.h"
 
@@ -54,6 +55,7 @@ void hydro_props_init(struct hydro_props *p,
 
 void hydro_props_print(const struct hydro_props *p) {
 
+  message("Adiabatic index gamma: %f.", hydro_gamma);
   message("Hydrodynamic scheme: %s.", SPH_IMPLEMENTATION);
   message("Hydrodynamic kernel: %s with %.2f +/- %.2f neighbours (eta=%f).",
           kernel_name, p->target_neighbours, p->delta_neighbours,